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This Changes Nothing

Chapter Text

Everyone knew the secondary gender trinary was bullshit. Secondary genders didn't mean a thing, and even if they did mean something to other people - like his friends, or parents, or doctors, or teachers - they still meant nothing to Bakugou Katsuki, which resulted in a zero-sum game, as far as he was concerned. The secondary gender trinary was like your blood type, or your zodiac sign. Something that boring people talked about when they had no real accomplishments to their name. As far as he was concerned, one’s secondary gender was an interesting but largely irrelevant bit of trivia. Alpha, beta, omega, none of it mattered, except to pathetic people with nothing better to think about. Secondary genders didn't mean a goddamn thing to Katsuki. They couldn't mean anything, because if they did, then Bakugou would never have what it took to be a true hero.

The secondary gender trinary was the only things separating him from heroes like All Might, Endeavor, even fucking Best Jeanist. Heroes like Eraser Head or Present Mic didn't share his secondary gender, either. But that was fine, because it didn't matter, despite what the media, popular culture, and commonly accepted wisdom stated to the contrary. Bakugou knew this because he knew himself. He knew he wasn't some pathetic weakling or simpering fool. When he wanted something, he got it. When he thought something, he said it. None of the supposed weakness or desperation attributed to his secondary gender would ever gain so much as an inch of ground in the battlefield of his life.

Still, if people saw Bakugou’s behavior as evidence of an individual expressing qualities generally equated with an alpha, that was fine with him. After all, it would be no worse than if people went around assuming his blood type was AB or some shit. Besides which, who fuckin’ cared what they thought?

Well. Maybe he cared a little.

It seemed like most people were obsessed with knowing the secondary gender of everyone they knew. Katsuki resented this - sometimes people would point to him and say shit like, “Of course he’s so strong and aggressive. He’s an alpha.” Bullshit! He was awesome because he’d worked his ass off from day one, not because of some stupid biological programming. He was determined to be the best, and it was infuriating that people - especially the media, after the disastrous conclusion to the UA Sports Festival - would write off his skill, determination and work ethic by ascribing it to a secondary gender they'd only assumed based on circumstantial evidence! Fucking. Bullshit. Acting like an alpha must mean he is an alpha, which explains why he's so fucking good at acting like an alpha. Fuck! What sort of twisted logic was that, anyway?

He couldn't even escape the theorizing at school. Being high school students, Bakugou and his classmates were reaching the point of maturity where their secondary genders were becoming more obvious, and locker room talk began to center around the topic of who in their class would be likely express certain characteristics. The whole idea of it was fucking gross, in Bakugou’s opinion. Everyone deserves their privacy, a person should be able to exist without having people follow them around, theorizing about their secondary gender. Of course when it came to making verbal predictions of who would present which characteristics, the repeat offender was grapes-for-brains, but as the year wore on Katsuki found himself encountering more and more conversations about the trinary. Even in public spaces where it should be highly discouraged. Fuck. Bakugou shouldn’t have to be the one telling people when their public behavior is inappropriate. But somehow, he seemed to be ending up in that situation more and more often. Like the time Kaminari told Kirishima what he’d learned from spying on the girls as they filled out paperwork for their annual health checks.

“I can't believe it!” Kirishima bellowed, showing no recognition that he was using his outside voice in an indoor space. Library windows rattled as Kaminari jumped back, not expecting quite this reaction to the juicy bit of gossip he'd gleaned earlier.

“I'm just telling you what I saw,” Kaminari protested.

Kirishima shook his head in amazement. “Yaoyorozu never struck me as the alpha type,” he declared, gesticulating wildly. “Hell, I would have put money on her being a beta!”

Kaminari shushed him, though Bakugou figured it was a moot point. The whole library had probably overheard the exchange. Not that he cared - he wasn't the one embarrassing himself. But he was starting to tire of their idle chatter. “Oi, rocks-for-brains,” Bakugo growled, tapping his textbook pointedly. “Quit yapping about useless bullshit and answer the fucking question!”

Kirishima looked chagrined. “I was just-”

“Wasting my time,” Bakugou interrupted. “If you and low-watt bulb over here want to gossip and giggle like a pair of nosy old women you can do it on your own time.”

Kirishima appeared properly cowed. He leaned over his textbook, making it about two sentences in before Kaminari commented in a stage whisper, “Turns out Jiro’s an alpha too.”

Kirishima's head jerked up again. “No way!” he shouted, “Seriously?”

“I'm just telling you what I saw on the health check forms,” Kaminari assured him at what had to be top volume.

“Would they lie on their forms?” Kirishima mused in what could nearly be considered an inside voice.

“Why the fuck would they lie?” Bakugou demanded irritably, only to realize, much to his chagrin, that he'd somehow been tricked into joining the conversation. “...the secondary gender trinary is all fuckin' bullshit anyway,” he added, mentally patting himself on the back for the smooth recovery.

Kaminari sighed gustily. “You would say that,” he bemoaned, “We all know you could have any omega you wanted.”

“Maybe,” Bakugou conceded, “But it'll be because I've become the greatest hero of all time,” Bakugou added with a snarl, “and not because of some body odor bullshit.”

“They're pheromones, not anything gross like that!” Kirishima protested, “They don't stink, just… smell funny.”

Maybe to someone like Kirishima, Bakugou thought darkly. But one unique characteristic of Bakugou’s own secondary gender was the inability to smell much of anything beyond surface level smells. Which basically meant that hulked-out alphas reeked fuckin’ constantly. Betas tended to assault the nose to a lesser extent than alphas, and omegas were usually tolerable except when they got close to heat. That was the extent of Katsuki’s smell powers - everyone smelled bad and could use more showers in a day. The worst of it was that alphas and betas could smell things, things like honesty and trust and fear and loneliness, but all Bakugou ever managed to smell served only to remind him of dirty old gym socks.

People with a secondary gender like Katsuki’s didn't have the sense of smell needed to sniff out subtleties. It's why they were expected to rely on others to negotiate. It’s why people with other secondary genders were told to ‘take care’ of people like Katsuki. How could one be expected to survive if they couldn't smell a lie, pick up a whiff of aggression, or recognize the heady scent of arousal?

Personally, Katsuki figured his technique of "explode first, ask questions later" got the job done just fine. He didn't need to smell anyone's pheromones if he could just as easily decide he didn't like their face, or the look in their eyes. And he usually did just fine, thank you. Even if these oh-so-important pheromones all just smelled like body stank to Katsuki. He himself showered several times a day to keep the smell of himself as mild as possible, but others were not so thoughtful. Whatever. His inherited nitro-sweat was at least a convenient excuse for the frequent showers. He’d have a harder time explaining that everyone, including himself, smelled like shit half the time. God, he hated people who refused to shower regularly.

“Do you think Uraraka’s an omega?” Kirishima asked Kaminari, changing the subject.

Bakugou growled and slammed his book shut, rising to his feet. “God dammit, why do I even fuckin’ try ?” he snapped.

“Where are you going?” Kaminari protested, suddenly oh so concerned with their study session.

“To finish my homework in the peace and quiet of my own goddamn room,” Bakugou answered sharply. “Have fun finishing up your gross conversation.”

“Hey wait!” Kaminari protested.

“We can focus on the homework now, really!” Kirishima added.

“Good,” Bakugou dropped his book back on the table with a loud noise. “Question nine.” Mercifully, the rest of the afternoon continued without further mention of secondary genders. None of the three noticed Izuku Midoriya watching them thoughtfully, half-hidden behind a towering stack of books, a slight frown creasing his brow as he considered one Bakugou Katsuki.

Time wore on, and across the school, students began to present ther secondary gender characteristics in earnest. Alphas went into rut, omegas, heat. Excused absences abounded, though most members of class 1-A had yet to produce evidence of their secondary gender. Fortunately for no one, Mineta had devised a plan to identify all the omegas in their classroom. He was explaining the plan to Sero and the other few students loitering in the classroom after lunch but before everyone was expected to be back in their seats.

As per usual, Katsuki was at his desk, arms folded, a look of bland disinterest and vague irritation on his face. He may have looked calm to his classmates, but inside, Katsuki was caught up in a maelstrom of emotion. Regretfully, he was not exempt from the bullshit biological changes that adults saw as a “rite of passage” from childhood to adulthood. As he neared the age of presentation, he was finding it harder to avoid acknowledging his own secondary gender. Gritting his teeth, Katsuki was mostly preoccupied, trying to forget the fact that his mother had called the night before. She had asked if he wanted her to accompany him to his upcoming screening with the family doctor. He did not.

Caught up in the thoughts swirling around inside his head, Bakugou didn't really pay attention to what was going down in the room around him. That is, until Mineta started waving his arms around, making a proper spectacle of himself. That was enough to draw Bakugou back into the conversation, if only to tell the purple-headed bastard to fuck off. He was prancing around, proudly showing off some weird cylindrical object in his hand. Upon closer observation, it looked like a can of hairspray. What the fuck? Bakugou sat up, intrigued enough to listen, at least for the moment.

“Now, this,” Mineta lifted his aerosol can demonstratively, glancing between the few people in the room (most of whom were still pointedly trying to ignore him) and wiggling his eyebrows, “is a little thing I got my hands on last week.” He smirked. “It's from an adult store. It has pheromones in it that will trigger an omega’s rut!” He waved the can tantalizingly. “All we have to do is spray it around the room before the girls get back, so that when class starts-”

Katsuki had heard enough, standing suddenly. “You can do what, rape our classmates because you can't keep your pathetic beta dick in your fuckin’ pants?” Bakugou interjected, seeing red. He marched towards Mineta menacingly, palm extended. “Hand it over.”

“No way!” Mineta clutched the aerosol can to his chest defensively. “Do you know the trouble I went through to-?!”

Bakugou let a few small explosions dance across his fingers, feeling a white-hot rage building up inside him. “I don't fuckin’ care.”

Mineta scowled. “It’s a harmless prank!”

“Harmless if you're not a fuckin’ omega,” Bakugou countered. He stared at Mineta, eyes sharp as flint. “Don't make this difficult,” he snarled, and lunged forward, ripping the can from Mineta’s feeble grasp. Just as he was about to toss it across the room into the trash can, Mineta made the stupid decision of trying to grab it back. Instinctively, Katsuki incinerated the can, which exploded in a whoomph of sickly-sweet scent that smelled like the taste of almost-burnt marshmallows. The contents of the aerosol coated him, filling the air with the smell of a cotton candy stand that had caught fire. Bakugou swore creatively and effusively, running to open windows and air out the classroom.

This was how the next classmate to return to the room found them - Mineta, howling pitifully about the loss of his beloved aerosol. Sero and Kaminari, exchanging awkward glances. Bakugou, throwing open windows, trailing expletives wherever he went.

Ashido was the first one to arrive post-incident. “What the hell?” she exclaimed. “What happened here? And why does Bakugou smell like the Wonka candy factory exploded all over him?”

“It fucking did,” Katsuki growled, before stopping to point at Ashido. “You an omega?”

Ashido scowled. “Not that it's any of your business, but no.”

“Good,” Katsuki said. “I’m going to go take a long-ass shower, you make sure this room gets aired out. Grapes-for-brains thought it would be a nice prank to fill the room with heat-inducing pheromones.”

Ashido glared at Mineta, her normally warm, inviting gaze growing cold and dangerous. “You didn't.”

Katsuki pushed past Ashido. “I need to scrub this candy stank off me,” he growled. “If Aizawa asks why I’m late, blame the purple shithead.”

He hurried down the hallway, trying not to spread the odor around more than was absolutely necessary to get him to the showers. He made it to the locker rooms and, after a split second of hesitation, went into the shower while still wearing his clothes. After all, they smelled as bad as he did, so he washed them first, then peeled them off to wash his body.

The water was warm, but Bakugou was boiling, practically incandescent with rage. How dare the purple snot attempt to out his classmates like that? It was more than just rude, it was infuriating. Bakugou slammed his fist against the shower knob, cutting off the stream of water, panting heavily. The room was filled with hot steam, and the thick moisture that hung in the air felt almost as suffocating as the awful sweetness of Mineta’s “prank” substance.

Katsuki growled low in his throat as he towelled off, reluctantly tugging on his gym clothes because who the fuck stashed an extra set of clothes at school? Not Katsuki. He also wasn't about to ask if there was some secret stash of extra uniforms lying around here, either. He didn't particularly like his uniform anyway. It hung loosely on his frame for a reason, and that reason was to minimize sweat. While he could actively excrete large amounts of nitroglycerin from the palms of his hands, it didn't change the fact that his skin excreted, all over his body, trace amounts of nitroglycerin. And that wasn't exactly a stable substance, so from a young age Bakugou’s father had taught him how to dress to minimize sweat and found him a pretty awesome spray-on antiperspirant that he used quite liberally.

The steam clouds were finally dissipating, though the room remained uncomfortably warm as Bakugou began towel-drying his hair, scowling at the empty locker room like he suspected it wanted a fight.

Across the room, the door to the hallway opened and Kirishima poked his head inside, catching sight of Katsuki. “Yo,” he said hesitantly. “Mister Aizawa sent me to find you.”

Bakugou paused, staring blankly at Kirishima. “You found me,” he said slowly. “Is that fucking all?”

Kirishima let himself into the locker room, shutting the door and sinking down onto one of the benches in the middle of the room. “Are you okay?” he asked hesitantly.

“Yes. Why?” Bakugou glared at Kirishima. “Do I not look okay?” his heart pounded furiously in his chest. Hard-headed freak, looking down on him like he needed to be fucking comforted.

“Kaminari told everyone that you confronted Mineta,” Kirishima explained, “And then ran away, which didn't sound like you, so we got worried, and…” he shrugged expansively, as if to say ‘here I am’.

Bakugou growled under his breath. His classmates were all a bunch of nosy motherfuckers. “I just wanted to wash away the stank Purple Balls put on me before it ended up fumigating the whole fucking classroom,” Bakugou explained slowly, as if speaking to a small child. A bead of water trickled down his forehead. Why was this room so fucking hot?

Kirishima but his lip. “For what it’s worth, Mister Aizawa sent Mineta to detention,” he said. “And he said he was proud of you.”

“I don't need his approval,” Bakugou snapped, wrapping the towel around his neck and slathering his underarms with a generous coat of antiperspirant. “I know when I did the right thing, I don't need some asshole following me around trying to tell me what I did was right or wrong.” He swiped at his face with the towel, trying to mop up the beads of sweat beginning to crawl down his temples. He tossed the towel aside, growling in frustration. “Why is it so fucking hot in here?” he complained, tugging at the collar of his gym clothes.

Kirishima glanced around, looking confused. “It’s not,” he said, eyeing Katsuki. “You do look flushed, though,” he decided.

Katsuki cursed under his breath. “If that grape-flavored munchkin’s crap made me sick I am going to make him wish he was never born,” he decided, eyes snapping like fire. He grabbed a water bottle, holding it to his forehead, relishing the cooling sensation. Maybe he just needed a cold shower.

Kirishima looked thoughtful. “Why would Mineta’s prank affect you if it only targets omegas?”

Bakugou lowered the water bottle slowly. “It blew up in my fucking face.” Anything that exploded in your face had the potential to cause problems. Katsuki should know, he had a lot of experience with things exploding in his face.

Kirishima shrugged. “If you say so.” His eyes were calculating, sizing up Bakugou like he was beginning to see something he’d never noticed before.

Bakugou didn't like the look in his eye. “Just say whatever the fuck you're trying to say,” he told Kirishima with a scowl, wrapping his still-dripping school uniform inside the towel before cramming the bundle into his gym bag. He hated it when people talked in circles.

“Are you an omega?” Kirishima asked suddenly.

Bakugou didn't stop packing his gym bag. “Wouldn't you like to know,” he scoffed haughtily.

“Bakugou,” Kirishima pleaded, taking a step forward, “Please. Man-to-Man, I swear I won't tell anyone. Are you?”

Bakugou zipped up his bag and rose slowly, staring Kirishima dead in the eye. “Go fuck yourself.” He flung the gym bag over his shoulder, marching out of the locker room. His ears were buzzing and he felt dizzy. He was hot, hot like when he stood at the center of a maelstrom of fire. But he wasn't exploding anything… yet. There would still be time to blow up shit later. Though, he was pouring sweat, and that wasn't good. Without his costume to collect the excess sweat, he would just be dripping soggy Nitro everywhere he went. He slammed the locker room door shut with a bang, striding down the hallway, guts churning with white-hot rage. Fucking Mineta was going to pay for this. Katsuki was going to wipe the floor with that little creep.

The locker room door swung open and Kirishima hurried out after Bakugou. “Look, dude,” he said, “I’m sorry, that was shitty of me-” He laid a hand on Bakugou’s shoulder, and his touch sang through Katsuki like a soft voice carried on a cool breeze.

Bakugou gasped, finding himself melting into the other boy’s touch. He stuttered to a stop, the dizzying pounding of his head and heart slowing as his body began to sink into an almost-trance. He wanted to press into the cool, soothing touch, but instead forced himself to pull away, staggering away from Kirishima on legs limp as wet noodles. “Who said you could fuckin’ touch me?” he snapped, though Kirishima seemed to be paying him no mind.

The redhead was staring at his own hand like it had bitten him. “What was that?” he wondered aloud, before reaching out and grasping Bakugou's forearm.

Katsuki felt the same cool sensation, like ducking into an air-conditioned convenience store and chugging a cold bottle of tea in the middle of summer. His knees wobbled. He stumbled back, yanking his arm out of the other boy’s grasp, but Kirishima reached towards him again, eyes glazed over. Bakugou punched him in the face, knocking the other boy to the floor. Then, he ran. He ran past his classroom, past the nurse’s office, past the dorms. He kept running, lungs burning, arms and legs pumping, until somehow, he was home.

He scrabbled in the mailbox for the spare key and let himself in, dropping his gym bag on the floor and heading for the bathroom. He was really hot now, practically feverish, and as he began to rinse himself off outside the bathtub, he began turning the knob colder and colder, trying to chase away the heat that seemed to be burning through him like a raging wildfire. Finally, in desperation, he climbed into the bathtub and began filling it with icy water, ducking his head under the tap to try and cool his face and scalp too. Once it was full, he lay in the cold bath, fire burning him from the inside out until his mother got home and saw his gym bag lying in the middle of the floor.

Chapter Text

Mitsuki Bakugou was not a patient woman - just ask her husband. So when she came home from a long day of work to discover that Katsuki had apparently let himself in and dropped his school bag in the middle of the room, she was understandably upset by this. What the fuck had the little hellion gotten himself into this time?  

“Oi, brat!” she shouted, stomping down the hall to his room, “There's no school holiday today! Did you get fucking expelled?” She kicked open the door to his room. He wasn't there. “Oi!” she yelled again, “Where are you?” she listened carefully, and heard the sounds of slashing from the bath. Stomping over to the bathroom door, she pounded on it with her fist. “Get out of the damn bath and explain yourself!” she commanded.

A weak groan sounded from inside, then, “Leave me alone, you old hag,” Katsuki retorted, though his tone held none of the usual venom, only a bone-weary timbre.

That wasn't like Katsuki at all. A sense of dread creeping over her, she pounded on the door again. “You have thirty seconds to make yourself decent, then I’m coming in there!” she threatened. If he’d gone and seriously injured himself and had somehow gotten disoriented… fuck! Wasn't the school supposed to be taking care of her son? What was he doing home in the middle of the day?

Inside the bathroom, Katsuki swore creatively. However, she heard some sloshing sounds a moment later, which told her that he knew she hadn't been making idle threats. About a minute later, Katsuki opened the bathroom door, towel slung haphazardly around his waist. “Happy now, you old bat?” he groused. His cheeks were flushed, his skin tinged red like he’d been in the sun for too long.

“How much of my hot water did you use?” his mother demanded irritably.

Katsuki made an ugly face at her. “None, I actually wanted the water to be fuckin’ freezing for once, you stingy old woman.” He wobbled, clutching the doorframe to keep himself upright. That's when she knew beyond a doubt that something was wrong - Katsuki never, ever showed weakness. Even when he was young, he’d always faced his injuries with aplomb, gritting his teeth and acting as though nothing was wrong. For him to behave in such a manner could only mean that he was very ill.

Her motherly instincts overtook her in that instant and she threw an arm around Katsuki to help him stand. She tried to guide him towards his bedroom, expecting some spirited resistance. Rather than pulling away and spitting insults, as he usually did when she was struck by the urge to behave in a matronly manner, Katsuki whimpered, burying his face in the crook of her neck and clinging to her in a way she couldn't remember him having done since he was three years old. She felt a bloom of warmth in her chest, and for a moment she thought it was just her long-lost motherly love, making a surprise reappearance.

It wasn't. Moments later, she realized what was really happening. “Katsuki! Did you go into heat?” She held her son out at arm’s length, studying him closely. “Fucking brat, why didn't you call?”

Katsuki blinked at her blearily. “What do you mean, heat?”

“Fucking hell, I’ve raised an absolute moron,” his mother declared, rolling her eyes skyward. “You were running an out-of-control fever that a fever reducer wouldn't cure and-”

“Fuck,” Katsuki said weakly, “I didn't take any of that shit.”

Bakugou’s mother glanced heavenward beseechingly, as if to say “You see what I have to work with, here?” before continuing to guide Katsuki towards his room. “Let's get you a fever reducer, just in case. If you don't get better, it’s safe to assume you've begun your first heat, and we’ll need to keep an eye on you tonight to make sure you don't require immediate treatment.”

“I don't need you to fuckin’ babysit me,” Katsuki growled, allowing himself to be moved to the bed without further protest.

His mother chose to ignore this, leaving Katsuki seated on the edge of his bed, wobbling dangerously. She stopped by the laundry room to retrieve a pair of pajama pants, which she tossed at him on her way to the bathroom medicine cabinet.  She dug around, finally locating some fever reducers that weren't expired and bringing them back to her son’s room along with a glass of water. Fortunately for everyone involved, he’d managed to dress himself in the pajamas, though his face was flushed and he appeared to be panting from exertion for some reason.

Struck by another wave of pesky mothering instinct, she reached down and brushed his damp, messy hair back from his forehead, another gesture Katsuki would have normally rebuffed. Instead, he mewled weakly, leaning into her touch. With a sigh, she took his hand and pressed the small tablets into his palm, handing him the glass of water as well. “Take these,” she ordered, waiting impatiently until he’d tipped them into his mouth and chased them down with a swallow of water.

Once satisfied that he’d taken the medicine, she tugged his shirt up and stuck a thermometer under his armpit. Katsuki grunted in protest, but did not attempt to remove it. His eyes were glassy and unfocused. She waited until the thermometer beeped, and yanked it out from under his arm, scowling at the result. “Well you've definitely got a fever,” she decided, sitting next to him and carding her fingers through his unruly locks.

Katsuki grumbled incoherently, sounding indignant. He did not pull away from her touch. For a moment she almost pitied him. However, both she and her son despised pity, as it was an overwhelmingly useless sentiment. Instead of feeling sorry for Katsuki, she lightly rapped her knuckles against his head. “Come home sooner next time,” she chided. “We’ll go see your doctor in the morning.”

She expected Katsuki to protest, but he did not. Instead, Katsuki leaned his head against her shoulder. She couldn't imagine where this sudden tenderness was stemming from, until he gave a light snore. Ah, yes. The tenderness borne of such deep exhaustion that one no longer gave two fucks about keeping up appearances. Mitsuki could relate. After all, she’d spent nearly twelve hours in labor when she’d given birth to the ungrateful whelp.

“You idiot,” she said almost fondly, leaning down and pressing a gentle kiss to his forehead before rising to her feet, gently easing him down onto the bed. She stared down at him for a long moment, watching his chest rise and fall with each breath. Shaking her head, Mitsuki Bakugou tucked her son’s blankets up around his chin before taking her leave, easing the door shut behind herself. As the latch clicked, she found herself stifling a giggle. Katsuki, in heat? Already? Her boy was growing up so fast! And what a shame that his attitude didn't mature at the same rate as his body. With a snort of amusement at the thought, Mitsuki Bakugou went to make the first of what would be several calls that evening.

When Kirishima returned to class, he was staring at his hands like they’d grown extra fingers. He dragged his feet as he walked back into the room, completely oblivious to the rest of the class, or what they were supposed to be studying. He stopped in the middle of the room, still staring at his palms. For a moment, no one said anything.

“Where’s Bakugou?” Mister Aizawa finally drawled, sounding almost bored.

Kirishima blinked a few times, at last looking away from his hands and glancing up at his teacher with confusion. “What?” he asked in a faraway voice.

Mister Aizawa sighed longsufferingly. “Where. Is. Bakugou?”

“Oh, uh… he left,” Kirishima answered weakly. His gaze drifted back to his hands, like there was something mysterious lurking just below the skin.

“Left school?” Midoriya piped up from his desk, sounding confused. “But Kacchan never skips class!”

“I didn't really ask,” Kirishima responded wearily, voice faint. He glanced over at Izuku and shrugged. “Maybe he went to the nurse’s office?”

“Seriously?” Ashido exclaimed, “Whoa, what did Mineta’s thing do to him?” she sounded almost worried. That seemed fair, considering it took a lot to get Bakugou to visit Recovery Girl.

Kirishima’s eyes seemed to be drawn inexplicably back to the palms of his hands. “I don't know what it did,” he said weakly. “Something … weird.”

Aizawa sighed, muttering incoherently under his breath. “Sit down,” he told Kirishima, “Let's at least try and get this class back on track.”

Kirishima nodded, moving sluggishly to his seat as though he were wading through waist-deep water. He still couldn't seem to stop looking at his hands.

Izuku frowned, worried. Kacchan rarely sought treatment for minor injuries. He hadn't been in the room when Mineta’s so-called prank had gone awry. Several others had filled him and the rest of their classmates in on the details of the confrontation. Basically, Kacchan thought that Mineta was gross and not taking class seriously, so he exploded the aerosol can, which had coated him in a strange pheromone substance. It hadn't sounded like an especially serious explosion, but Kirishima seemed almost shell-shocked and Kacchan had gone to the nurse’s office. What could have caused Kirishima so much distress, and driven Kacchan to seek medical assistance? It had to have been bad.

Had the explosion somehow injured Kacchan’s hands? Was he all right? Had it affected his quirk somehow? Izuku glanced around the room nervously, and realized he was not the only one. He made eye contact with Ochako, who shrugged, and made a face that seemed to say ‘I don't know what’s going on and I don't like it’. When Izuku made eye contact with Todoroki, he raised a single eyebrow. Kaminari looked utterly baffled, though, that was pretty much par for the course during school hours.  

Izuku tried his best to focus, taking good notes and scribbling down key details - Kacchan might need a copy of someone's notes, after all. Unfortunately, none of the students in Class 1-A paid much attention to the information being taught that day. Once the bell rang to let school out, Izuku and several others mobbed Sero and Kaminari, the only other two people who had been in the classroom when Bakugou had exploded an aerosol can in his own face.

“Did he seem hurt?” Izuku demanded frantically.

“He seemed pissed!” Kaminari yelped defensively. “But he’s always pissed, especially when people bring up secondary genders. I didn't see anything else!”

Izuku turned to Kirishima, “What did he say to you?”

Kirishima seemed to be less out of it by then, though his only response was to shake his head dejectedly. “He just told me to leave him alone,” he said. “And he ran off.”

Now Izuku was really confused. “What do you mean ‘he ran off’?” To his knowledge, Kacchan had never run from a confrontation in his life. It didn't make sense that he would start now! Running to something was a very Kacchan-like attitude. Chasing down an opponent, definitely. Charging headlong into a fight, sure. But running away? Not Kacchan. “That doesn't sound like him.”

“All I know is he punched me and then ran away!” Kirishima nearly yelped, not appreciating the intense scrutiny he’d suddenly found himself under. “All I did was pat him on the shoulder and he freaked out at me!”

The freaking out part did sound like Kacchan, Izuku decided. On the other hand, it took a lot more than a harmless pat to make Kacchan run. Though, considering how much Kacchan hated pity, maybe he saw the friendly pat on the shoulder as a form of pity? But that would have made him angry, not make him run away… Maybe when Kirishima touched his shoulder it had made him realize that he was injured in some way, and that's why he’d run off.

“Deku, you're thinking out loud again,” Ochako stage-whispered.

Izuku blinked. “Oh, right,” he turned to Kirishima. “Sorry.”

Kirishima shrugged. “It's fine.”

He didn't sound like it was fine, but Izuku wasn't going to push him on it, since it sounded like he wanted it to be fine. Or rather, he didn't have time to push it, because he needed to get going. “Well,” Izuku said, glancing around at his classmates, “I’m going to the nurse’s office to check on Kacchan.”

Kirishima stiffened slightly. “I think he wanted to be left alone,” he said weakly.

Izuku frowned at Kirishima. It was obvious that there was something the redhead wasn't telling him. He couldn’t meet Izuku’s gaze, and he still seemed to be frightened of his own hands. Kirishima was an open book, and Izuku could clearly sense that something wasn't right. “What aren't you telling me?” he demanded.

“It's… I can't tell you,” Kirishima responded, still unable to lift his gaze to meet Izuku’s. “Besides, I don't have any real proof.”

Izuku frowned. He had no idea what Kirishima meant by ‘proof’, but if he didn't think it was right for him to elaborate, then Izuku wasn't going to push him. Though admittedly, the idea that Kirishima might know something about Kacchan that his childhood friend didn't know was unlikely, though Izuku supposed it wasn't impossible. “Okay,” Izuku agreed, “If you think it’s better to leave it alone, I’ll trust you on this.”

Kirishima seemed to deflate, like he’d released a huge amount of tension in that single moment and couldn't figure out how to stand tall without the pressure. “Good,” he said, his eyes flicking up to meet Izuku’s, then returning to his hands. “Good,” he said again, softly.

Izuku wondered what had happened to make Kirishima so focused on something as mundane as his own hands, but decided it might be too tactless to ask, especially in front of everyone. Instead, he packed up his books and headed for the dorms. He hoped that wherever he was, Kacchan was okay.

Katsuki was not okay. He realized this right around the time he heard his mother yelling at him and holding his face, her hands on his cheeks two spots of blessed coolness in a raging inferno. He’d sweat through what felt like his entire mattress. Everything around him was wet and reeked of sweaty teenager. Fuck. He tried to say something to the effect of get off of me, woman, and let me shower, for fuck’s sake, but all that came out was a dry croak. That’s when he realized there were other people in the room, two men in blue uniforms and white helmets, his mother was helping him to his feet, and he couldn't seem to get his legs to work, knees buckling every time he tried to take a step. One of the men guided him into - fuck, a wheelchair? Katsuki didn't need a wheelchair, he was perfectly healthy! His mother’s touch slipped away and Katsuki felt like his chest was ripping open, heart and head pounding like taiko drums at the local shrine’s summer festival. His vision blurred, and when he blinked it clear, his father and mother were hovering over him and he was lying on his back on a gurney, getting loaded into - why the hell was he in an ambulance, fuck that, he didn't need to go to the hospital, he just needed a shower! His mother was stroking his forehead gently, and the paramedics were placing cold packs around his body. They didn’t seem to be making a difference, as Katsuki still felt like he was burning up from the inside out.

The ambulance doors closed and Katsuki could hear the paramedics asking his parents questions, though they sounded far away, as if he were lying alone at the end of a long, echoing tunnel. “Fuckin’ munchkin got me good,” Katsuki ground out, his mouth as dry as the Sahara in a heatwave.

His parents and the paramedics all turned to him, shock evident on their faces, despite how blurry his vision had become. His mother leaned over him with a frown, asking him something, but Katsuki couldn't hear well enough to make out any distinct words. Whatever, it was his turn to speak now anyway.

“Brought a,” Katsuki had to suck in another breath before forging on, “a heat-trigger to school.” His vision began swimming with black spots and he sucked in another breath, his heart pounding so hard he thought it might bust his ribcage. “Blew it up in my face,” he managed to finish the thought. Everything he wanted to say seemed to be slipping away like water between his fingers. He could hear his parents and the paramedics asking him questions, but like his vision, their voices seemed to be fading to nothingness. He had more to say, obviously, but he couldn’t seem to wrap his mind around the words long enough to get them to his mouth. “Tired,” he managed to say as everything faded to black.

Chapter Text

Katsuki couldn’t remember much more than flashes of what had happened after he’d run home from school, but he felt certain he would have remembered falling asleep in the world’s most uncomfortable bed. He could hear swishing sounds of doors, distant beeps and whirrs of machinery, and hurried footsteps just loud enough to be disruptive. His eyes burned and his head pounded like someone had taken a sledgehammer to the inside of his skull. Maybe if he just lay still, he could fall back asleep, though with how uncomfortable this bed was turning out to be, that seemed doubtful. Just as Katsuki was beginning to relax on the concrete slab of a mattress, he heard the sound of a door opening and loud footsteps marching towards him.

“Well Katsuki, you may have given us all a right scare for a bit there, but you seem to be doing much better now,” came an overly-cheerful voice, splitting Katsuki’s skull like an axe through a log.

“Goddamn, why are you so fucking loud?” Katsuki griped, mostly on instinct. As he inhaled, his nostrils caught a whiff of the most repugnant odor with which he could ever recall having come in contact. It smelled like two gym bags had been locked in a room together for a year, just… percolating in malodorous union. Fuck, it was bad. His stomach lurched. “And what the hell is that godawful smell?”

Katsuki felt someone - probably his mother - rap the side of his head with her fist in a gesture just this side of a ‘love tap’. “Show some respect, Katsuki, this doctor probably saved your goddamn life last night!”

Katsuki pried one eye open, casting his gaze to the right. His mother sat in an uncomfortable-looking chair beside him, deep circles under her eyes. She looked relieved. Also pissed. So he probably wasn't dying anymore. Good. Katsuki took a moment to glance around the room, quickly realizing that for some fucking reason he’d been taken to the hospital. “Why am I here?” he demanded.

“Well, Katsuki,” said the overly cheerful voice of his doctor, accompanied by an overly friendly smile and a glimmer of humor in his eyes, “Your heat was triggered early.”

“No shit,” Katsuki grumbled, managing to open his other eye in order to unleash the full force of his glare. The effect was somewhat minimized when his mother pressed her knuckles against the top of his head and twisted her fist back and forth while scolding him and demanding that he behave.

To his credit, the doctor continued speaking as though he'd never even been interrupted by a crabby teenage boy. “Whatever it was that triggered your heat was a slow-acting stimulant that seeped into your skin, continuing to activate the glands that release pheromones and trigger your heat. This chemical caused your body to continue producing those heat hormones long after the natural process would have concluded.” He shook his finger at Bakugou as though scolding a naughty child. “That, young man, is why you don't play with adult -ehrm- stimulation enhancers. Careful supervision is key when you're experimenting with your sexuality.”

Fuck this guy, Katsuki thought. How dare this asshole doctor talk to him like that when his parents were literally sitting on either side of his hospital bed? Was this doctor really trying to give him the birds and the bees talk? Hell no. “It wasn't like that. One of my asshole classmates was trying to spray some heat trigger shit around the classroom as a prank,” Katsuki snapped, “because he’s a fuckin’ perv.” He struggled to sit up, eyes ablaze with rage. “I wasn't experimenting with shit. I just confiscated my classmate’s stupid ‘sex in a can’ …explosively.”

The doctor’s eyes widened in surprise. “I see,” he said weakly. “My apologies.”

“Next time ask before you start assuming things,” Katsuki snarled. Part of him didn't exactly blame the doctor. If most of his classmates were too preoccupied with the presentation of secondary gender characteristics for Katsuki’s comfort, they were probably making adults feel weird about it too.

Masaru Bakugou stepped in before Mitsuki had the chance to start bodily shaking Katsuki for speaking so disrespectfully to the doctor. “Katsuki, whatever the reason for your exposure, it doesn't change the fact that you should have called for help after the incident. If you had been suffering its effects alone, you could have had a seizure, or even died.”

Katsuki opened his mouth to argue, but his father was staring at him with a solemn, disappointed stare, and Katsuki decided that it was hard to argue with a statement like ‘if you feel sick get treatment’. “Fine.”

“Now Doctor, if you wouldn't mind explaining exactly what treatment you used for Katsuki?” His father continued, gazing expectantly at the doctor.

Katsuki glowered at the doctor. He didn't particularly like him, but he did want to know what had been done to him, so he gritted his teeth and waited to hear what they’d done to him in this sterile cell block of a medical facility.

“Well Katsuki, you mentioned a distinctive odor,” the Doctor began.

Katsuki felt that was putting it mildly, and opened his mouth to say so. His mother gripped his wrist tightly, and after a moment, Katsuki decided his smart remark wasn't worth the shouting match that would be certain to follow.

“That odor you smell is one side effect of a surprisingly common hormone treatment designed for omegas with hyperactive glandular disorders,” the doctor explained.

Katsuki was going to point out that he didn’t have a glandular disorder, but before he could make that point, the doctor continued.

“We aren't yet sure if this episode of yours was a singular event triggered by your classmate’s prank, or something more permanent.” The doctor explained. Katsuki found himself suppressing the urge to bury his fist in the man’s simpering face. Of course this wasn’t permanent, this was all Mineta’s fault. He was fine. He was going to be the greatest hero ever. He wasn’t going to be held back by something as stupid as a prank gone wrong.  

The doctor continued to speak, and so Katsuki forced himself to refocus on what the doctor was telling him. “In either case, we’ll keep you under observation for a few more hours, then send you home with enough doses of this treatment to last you through the duration of your heat. When your next heat approaches, we’ll check back in to see how your hormone production looks, and reevaluate your treatment plan at that time.”

Katsuki didn’t like the idea of being forced to come back for some bullshit evaluation about something that was obviously the fault of his perverted classmate and definitely had nothing to do with his own biology, but he didn’t want to argue with the doctor any more than was necessary to get out and back to school. It was still early, and the doctor had said they only wanted to watch him for a few hours. Maybe he could even make it to UA in time for morning classes, though he would miss his usual morning workout. Just another thing for which Mineta was going to pay dearly. “So I’m free to go,” he said.

The doctor nodded slowly. “In a bit,” he clarified.

“Does that mean I can go to school?” Katsuki demanded. Fuck, what if the purple cretin’s prank actually made him stay home from school? He was going to choke the life out of Mineta for costing him half a day of training, much less the midnight hospitalization. Staying here for an undetermined amount of time so that doctors could feel better about themselves did not appeal to Katsuki in the slightest. UA had a nurse’s office, didn't it? If he started feeling sick again he could go see Recovery Girl.

The doctor glanced at Katsuki’s parents, which made Katsuki nervous. For a moment, he thought the doctor was going to tell him no , but when he turned to Katsuki, he had a smug half-smile plastered across his stupid face. “If you feel up to it,” the doctor replied cheerily. He was up to something, Katsuki could tell that much. But he also didn’t care, as long as he could get the fuck out of the hospital and back to school.

Katsuki swung his legs over the side of the bed. “Let’s get out of here,” he said to his mother, and was about to stand up when he felt a horrible feeling overtake him. It was like someone had reached down his throat, grabbed his stomach in their meaty fist and shook his guts around like a dog with a toy. He dropped his head and tried to breathe through the muscle spasms, tasting sour bile clawing up his throat into the back of his mouth. He crumpled over, arms wrapped around his torso as his body shook. After dry-heaving a few times, Katsuki finally managed to catch his breath as the wave of sickness passed.

“Ah,” the doctor said mildly, “that would be another side effect of your treatment.”

Katsuki took a shaky breath, swallowing back the taste of stomach acid in his mouth. “That's nothing,” he said, trying to project a confidence that he no longer felt. “I’ve puked harder than that after some of my morning runs.” It wasn't necessarily true, but Katsuki was not going to let a little thing like an upset stomach or the worst smell known to mankind hold him back. He was going to be the world’s greatest hero, and nothing as insignificant as a heat gone wrong was going to keep him down. Unfortunately, now his parents were exchanging nervous looks. Goddamn, the doctor was a piece of work. If he’d warned Katsuki about the nausea, he would have been able to control his reaction better, and then his parents wouldn’t be actively considering keeping him in this fucking prison people called a hospital. He stood, clenching his fists and swallowing hard to keep the nausea at bay. He would not look weak. Not to the doctors, not to his parents, not to anyone. He was going to school, dammit! He was not going to spend another minute laying in some lame-ass bed, smelling like shit and barfing all over himself. Fuck. That.

“I can go now,” Katsuki declared. “I feel fine.”

Again, his parents exchanged looks.

The doctor appeared amused by his statement. “Really now?”

Fuck. “Yes,” Katsuki snarled, “you asshole. I’m fine, you said the treatment is working, just tell me what other side effects to expect and I’ll fuckin’ handle them with grace and poise and shit.” He wobbled a little, and pretended not to have noticed. He saw his parents exchange another worried look. Fuck.

The doctor did not appear worried at all, simply amused. “Well, Katsuki, side effects include olfactory sensitivity, nausea, vomiting, dizziness, periodic visual impairment, neuropathy of the extremities, prolonged periods of muscle weakness or cramps, and in rare cases, one might also experience severe vertigo, migraines, heavy nosebleeds, ulcers, or kidney failure.”

Katsuki blinked. “Fuck. Why am I on this shit, again?”

The doctor smiled condescendingly. “It’s the only thing keeping you functional and coherent.”

Katsuki blinked. “So without the treatment, I’d be, what, in a coma?”

The doctor nodded solemnly. “Essentially.”

Katsuki swore creatively. Surprisingly, his parents did not scold him. In fact, if the look on his mother’s face was any indication, she’d probably produced a similar volley of expletives when she’d been given the same news several hours earlier. “Well, fuck,” Katsuki finally decided. “If I’m going to be fucked either way, I’d rather be fucked at school.” He headed for the door, determined to do his best, regardless of the worst-case scenario in which he’d found himself. He turned back around to eye his parents. “Mom? Dad?”

Mitsuki Bakugou stood, turning to the doctor. “Was there anything else you needed?”

The doctor made a face. “We’d like to keep him under observation here…”

“Fuck no,” Katsuki declared. “I’ve wasted enough time in this hellhole already. If I feel sick I can go to the nurse at school, she can decide what to do from there.”

With a sigh, the doctor relented. “But ultimately, there’s no immediate reason to keep him here.”

Masaru Bakugou stood also. “Thank you for your help, doctor.” He moved around the bed to join his wife, and together, the two of them moved to the door to stand beside Katsuki.

“You are welcome,” the doctor answered, then turned to Katsuki. “Take care of yourself.”

Katsuki scowled at him. “I always do,” he snarled, kicking open the door and stomping into the hallway before stopping dead in his tracks, sucking in a breath and holding it as the hallway spun crazily around him. He could feel, more than see, his parents stop, one on either side of him. Katsuki could sense his mother reach out, about to hold his arm, then stop herself, allowing her hands to drop to her sides. He could feel his stomach churn, rising up against him, and with great effort he willed his body to behave.

Finally, the building around him settled back into the simple fluorescent-lit hallway from before his body tried to play tricks on him, and he could begin moving forward again. He hated what this medicine was doing to him, but what he really despised was how his doctor could be so glib about a treatment that was ruining his life. How was he supposed to become the greatest hero of all time when he could barely walk without puking? Fucking. Bullshit.

Katsuki stomped forward, shutting his eyes when the hallway began to spin around him again, laying a hand on the wall and stomping forward by sheer muscle memory. He felt like the world was tilting around him, forcing him to rely solely on the sensation of his palm on the wall, his feet on the floor, walking without relying on his sense of balance. He wobbled, stopped, gritted his teeth, and placed one foot in front of the other, doggedly continuing his slow march down the hallway. This wouldn’t stop him. Nothing would stop him.


When Kacchan actually came to class the next morning, he was mobbed by his classmates. As expected, they were instantly rebuffed by the object of their attention. Kacchan hated to be pitied, and their expressions of concern were probably too close for comfort when it came to the explosive hero-in-training. Izuku forced himself to hang back, knowing that Kacchan would never tell anyone even if he had been sick, and asking him to talk about his weakness was only bound to make things more awkward for everyone involved. That didn’t stop the others from crowding around the explosion-quirk user with a volley of loaded questions.

“Bakugou! What happened? Are you alright?” “What happened yesterday?” “Why did you leave?” “Are you feeling better now?” “Did you go to the nurse?” “Were you sick?” “Did you get injured?”

Kacchan turned on the people crowding around his desk with eyes that could melt solid stone. “Get the fuck away from my desk and leave me the hell alone!” he snarled, pounding a fist on his desk. Izuku was a little surprised that Kacchan didn’t punctuate this with an explosion, as that was his usual modus operandi.

When the others realized they weren’t going to get anything more from Kacchan than enraged ranting, they shuffled back to their seats, leaving Kacchan to smolder furiously in his seat. He sat slumped, eyes burning with an inner fire fueled by rage. He took notes like his pen was a knife, slashing at his paper furiously. Izuku couldn’t seem to take his eyes off him. Kirishima seemed similarly taken, and while he hadn’t been one of the people to crowd around Kacchan’s desk, he seemed similarly concerned for Kacchan’s wellbeing. Izuku couldn’t understand why Kirishima wasn’t talking to Kacchan about it, though. He was probably the closest thing Katsuki had to a friend, and Kirishima wasn’t the reticent type. It seemed off, somehow.

There was one other thing that had Izuku reeling - Kacchan stank. He usually showered a lot, which was just something you should do when your sweat glands produce nitroglycerin. But his regular showering generally meant that his scent was fairly mild. When you could smell Kacchan, he generally just smelled pissed off, or aggressive. Which was something that could be discerned easily enough by just looking at him. But today, Katsuki was actually putting off a scent, and it was strong. Even more strangely, it wasn’t aggression, or frustration, or any of the usual Kacchan emotion smells. He smelled of something far more lewd, his scent spiked with something bawdy and lascivious, carrying an undercurrent of salacious satisfaction.

Izuku didn’t know what a post-coital alpha smelled like, but if he had to hazard a guess, he would say they smelled exactly like Bakugou Katsuki did that morning. It was almost indecent, coming to school smelling like that. Not that Izuku was going to say anything about it; Kacchan didn’t appreciate his input on the best of days, and considering the disaster that had been yesterday, Kacchan would not be ready to hear any sort of constructive criticism from him for weeks.

That didn't keep Izuku from wondering about so many things. Had the pheromones from Mineta’s aerosol triggered a rut in Kacchan? That didn't make sense. From what he understood, it had been targeted specifically towards omegas. Had Kacchan’s clothes and body carried enough of the aerosol’s contents to trigger a nearby omega’s heat? Had the explosive teen taken advantage of an omega? Izuku never wanted to think poorly of a person, especially not his childhood friend, but anyone who knew Kacchan had to admit that the boy had an unhealthy perspective on concepts such as weakness. In Kacchan’s world, the weak existed to be exploited or rejected by the powerful, depending on the situation. Would he have exploited an omega in heat, or rejected them? Based on how Kacchan smelled, Midoriya couldn't help but worry that Katsuki had used an omega’s heat to his own advantage.

Katsuki whirled around to glare pointedly at Izuku. “Hey, Deku, have you ever tried not thinking out loud and just fucking asking, y’ damn nerd?” His eyes snapped, ablaze with fury, and Izuku realized that he’d been thinking aloud again, and loud enough that Kacchan had caught the gist of what he was thinking about.

He immediately felt embarrassed. He didn't mean for Kacchan to overhear his thoughts, especially when they were not particularly flattering to him or his character. He didn't think it was very kind to make people listen to what people thought of them, although Kacchan seemed immune to the opinion of everyone but himself. It may seem like confidence to the untrained eye, but Izuku felt that Kacchan’s unwavering opinion of himself was more aptly described as arrogance.

Katsuki planted his palms facedown on his desk and stood suddenly. “Oh my fucking god, Deku, if you don't shut up I am going to blow your damn face off and I won't even feel sorry.”

“You never feel sorry,” Todoroki muttered from across the room, and Katsuki whirled on him, pointing a finger in his direction. “Say that again, you fuckin’ half-and-half bastard! Goddamn, you all are fucking infuriating! Shit!” He sat back down as suddenly as he’d stood, pointing at Mister Aizawa. “Don't stop on my account, teach. You were talking about the finer points of listening to accident victims to get a better idea of the immediate situation, right?” He turned to glare at Izuku as if to say ‘ you could learn a thing or two from this.’

Mister Aizawa blinked, unamused. “Do I need to call parents, or are we all going to sit still and pay attention to the lecture now?”

Kacchan was gripping his pen like he wanted to choke the life out of it as he breathed loudly through his nose, but he wisely chose to say nothing.

“Good,” Mister Aizawa said blandly, and continued with his lecture as though he’d never been interrupted.

Izuku tried to pay attention, he really did, but his attention kept drifting, and before he realized it, class had finished and everyone was headed for the locker room to change into their gym uniforms. Everyone, that is, except Kacchan. He sat stock-still, as though he’d been frozen in place. His face was a mask, and Izuku found himself seeking a sign of life in those scarlet eyes. “K-Kacchan?”

The other boy didn't even turn to look at him. “Keep walking, Deku.”

Izuku didn't want to keep walking. He was worried, genuinely concerned for the other’s well being. “Are you-?” Izuku began, but before he could get any further, Kacchan had him by the collar, his hand sparking dangerously. The boy hadn't even stood up to confront Izuku. Instead, Kacchan had pulled Izuku down to match his seated eye level, Izuku’s shirt caught fast in the other boy’s iron grip.

“Not today, Deku,” he snarled, teeth bared, eyes feral. He shoved Izuku back, nearly knocking him over. “Stay the fuck away from me.”

Izuku bobbed his head nervously in agreement. “Okay,” he agreed, “but you'll tell someone if you're not okay?”

Kacchan just looked at Izuku as if he’d grown a second head, “There’s nothing wrong with me, you piece of shit. Leave me alone!”

Izuku didn't believe him, but he also doubted that pressing the issue would prove beneficial for either of them. With a sigh, he pulled himself to his feet, moving away before pausing, one hand on the door. “You'll have to open up to someone eventually,” he said quietly. “I just thought you might want someone to talk to.”

“When the hell have I ever implied that I see you as someone worth talking to?” Kacchan snarled. “Leave.”

Silently, Izuku left.

Chapter Text

Once Deku finally left the room, Katsuki could focus all his efforts on standing and walking to the locker rooms without puking all over everything. He’d made the mistake of grabbing a salted rice ball from a convenience store on his way to UA, and now his stomach seemed determined to bring his breakfast up for an encore. Katsuki gripped the edges of his desk, knuckles white with strain. “Fuck,” he hissed, then stood, keeping his hands on the desk. The room around him pitched and rolled, and one of his knees nearly buckled. He breathed through the vertigo, then walked for the door as quickly as he dared. In the hallway, he kept his hand on the wall for stability, eyes half-closed to minimize the confusing visual input he was getting, focusing on his feet, the wall, not balance, just movement. He placed one foot in front of the other methodically, making his way to the gym with caution. He had to take it easy now, because once he was with his classmates again, he would need to pretend that nothing was wrong.

He reached the locker room door, centering himself for a few moments before kicking the door in and stomping past several classmates. Throwing open his locker with a bang, Bakugou fumbled for his gym clothes, finding them before shucking his uniform. Most of his classmates were finished changing already. He could feel someone’s eyes on him, and he looked around the room, locking gazes with Kirishima. He narrowed his eyes at the red-haired boy. Kirishima had the decency to look embarrassed, and he quickly turned his head. Katsuki went back to changing, breathing in short bursts through his nose, swallowing to keep down whatever was fighting it's way up from his stomach.

The class trickled out of the locker room and onto the field, where Aizawa was waiting for them with a bland look on his face. Behind him stood All Might, beaming like the sun, fists resting on his hips. Aizawa waited until everyone had made it onto the field before explaining, “We’ll be doing some sparring today - nothing too heavy,” here he glared at Bakugou, as if he was the only one who ever took things too far.

Katsuki narrowed his eyes at the teacher and tried not to wobble. Damn, he was fucking dizzy . He didn't like it, but there was no way in hell he was going to bow out over a little queasiness. His body would just need to deal. Heroes didn't go running away when situations got tough, they rose above them! He would be fine. Probably.

Aizawa referred to a note card he held in his hand. “While two of you spar, the rest of you will be doing mild training - enough to stay loose, nothing too dramatic. Again, he looked at Katsuki, which didn't even make sense, since Deku was the one who tended to over exert himself, not Katsuki.

Fuck! His mother must have called the school and told them he was dying or some shit. He wanted to tell Aizawa that he would go to the nurse when he needed to and not a moment sooner. He knew what his body could handle better than anyone else, fuck you very much. But he also didn't want to call attention to the fact that he might be getting special treatment, because that would only result in questions that Katsuki absolutely did not want to answer. So he continued glowering at Aizawa until the teacher shrugged minutely.

“Our first match will be…”

Bakugou tuned out the names and instructions, they would be easy enough. Use your quirk wisely and carefully with finesse , don't rely too heavily on any one skill or advantage, take it easy, don't kill anyone, and try to learn something. Basic sparring rules. Once the first duo headed into the field, Bakugou began jogging lightly around the perimeter with a few other students. He quickly realized this was a mistake, as he was having trouble feeling the ground under his feet properly. He knew he was weaving and he didn't want people to think he was struggling, so he slowed his jog to a sedate walk, placing his hands behind his head as though stretching, closing his eyes when the landscape began to swirl around him, relying instead on the sounds of his classmates jogging to maintain his trajectory. Once he’d finished the lap, he wandered off to the sidelines to do some squats, trying to look nonchalant. He wasn't sure how well he’d pulled it off, considering the close scrutiny of his classmates. Whenever he caught someone staring, he would make an ugly face at them until they looked away. This continued for several minutes, and Bakugou found that he was actually beginning to regain a sense of solid earth beneath his feet.

Then Aizawa called his name. “Bakugou! Todoroki! Get over here.”

Bakugou stood carefully, slouching his way into the field. He still couldn't see right, and his stomach was trying to forcibly remove the rice he’d eaten earlier. He swallowed hard, glowering at the half-and-half bastard, who appeared nonchalant, checking his fingernails as he waited for Katsuki to reach the center. He glanced up when Bakugou finally arrived, and nodded minutely.

Aizawa sighed longsufferingly. “You know the rules. Take it easy, no cheap shots, keep property damage to a minimum.” He glanced between the two of them, “Go.”

Todoroki lifted a hand, ice crackling out from where he stood. Katsuki leapt sideways, using a small explosion to propel himself away, twisting in midair to land on his feet. Except with the vertigo, he couldn't seem to find the right trajectory, so he landed flat on his stomach. The air in his lungs escaped in a whoosh, and Katsuki found himself suddenly fighting for air as well as balance. He scrambled to his feet, firing off a few explosions to distract half-n-half while he considered his options. He couldn't use his instincts for this fight, his own sense of equilibrium was failing him. It was like he’d been touched by round-face, except only in his head. His body felt weightless, listing to the side. With a roar, he charged at icy-hot, deciding that the best way to survive this was to end it quickly. Fuck, why did he have to fight this asshole? The guy was actually a decent challenge for Katsuki on his best days, much less a day like today.

Todoroki sent spears of ice up into the air, and Katsuki exploded them, but as he twisted in the air, he realized with horror that he was going to land on the ice below him. He fired another explosion, trying to propel himself away from the ice. It worked, but as he did so, his quirk sputtered. Just a little, not enough that anyone else would notice, but he noticed. He felt his blood run cold. That wasn't supposed to happen. His quirk had been a constant, and the doctor had said nothing about his quirk being affected by this, so why was it failing?

By some miracle, Bakugou managed to land on his feet, but his mind was swimming with the terror of what if I can’t use my quirk? He charged at Todoroki, firing explosions that he couldn't seem to manipulate with the same ease to which he’d grown accustomed. With each detonation they grew weaker until the crackles coming from his palms barely qualified as party tricks. It felt like there was something blocked up in his arms, like something was just missing. His palms were dry.

He leaped sideways to avoid one pillar of ice, and tried to fire an explosion at a second pillar, but his quirk wouldn't activate. Panic flooded Katsuki’s system as he collided with the ice, scraping up his palm as well as earning a fat lip and a bloody nose. He flexed his fingers, dodging more ice as he tried to produce an explosion, a spark, anything. Nothing.

His eyes widened in realization as he looked up, seeing a pillar of ice coming right for him. Katsuki leapt aside, but without the added propulsion of his quirk, the ice clipped him in the ribs, spinning him wildly through the air. He couldn't see anything, couldn't sense the earth beneath him, and when he hit the ground he tumbled across the field like a rag doll.

Katsuki immediately struggled to his feet, only to feel his stomach twist up inside him, wrenching his chest and intestines like two giant hands were trying to wring out his innards. Bakugou bent over and puked so violently that the vomit came out of his nose, too. His body shook with the force of it, and he heaved once, twice more even after he’d emptied his stomach. Distantly, he could hear the concerned murmurs of his classmates, and Aizawa was scolding him, though Katsuki couldn't make out the words. His ears were ringing, his breath coming in shallow gasps. He lifted his head, glaring at anyone who might be tempted to approach.

Todoroki was walking across the field towards him, a look of remorse plastered across his features, contrition oozing from every pore. Katsuki gritted his teeth, feeling his rage building up in him like a thunderhead. How dare he look at Katsuki like that? They were equals, dammit! No, not even equals. If anything, he should be looked at with awe, not fucking pity. So why was everyone looking at him with worried faces? It was nothing, just a little puke. They had no reason to think it was anything more serious than that! What the hell was wrong with his body?

Katsuki felt a hand on his shoulder, and it soothed his rage like a balm. He looked up to see All Might, eyeing him with concern. What the fuck was he doing, trying to comfort Bakugou? Hell no. Katsuki pulled away, staggering a few steps before he could find his balance. “I know, I know,” he snarled. “I’ll go to Recovery Girl.” He started marching across the field, only to spot several of his classmates following him. He spun around. “Fuck off!”

Aizawa was standing next to him. Fuck! When had the teacher moved? Bakugou felt like time was coming undone around him, moving fast, then slow. He felt warm. A thought occurred to him - in his rush to get out of the locker room, he’d forgotten to take his second dose of medicine. No wonder he was feeling like this. “I left my meds in the locker room,” he told Aizawa, trying to sound nonchalant, not missing the pointed looks being exchanged among his classmates. Shit. He’d have to come up with an explanation for that to keep them off his back.

“I think we're past the point where your medicine would make a difference,” Aizawa told him, reaching out to steady him.

Katsuki pulled away. He didn't need help standing, and even if he was wobbling a little, that wasn't enough to excuse the unwanted contact. He scowled at his home room teacher, and then the heroics studies teacher for good measure. “I’m fine,” he spat, storming across the field. He nearly stumbled into the doorframe, catching himself before stomping into the locker rooms to recover his meds. He shook a pill into his palm and dry-swallowed it, deciding he didn't have time to change and shower if he wanted to get to Recovery Girl’s office before his classmates or teachers came after him. With a frustrated growl, he stomped out of the locker room and down the hall. This sucked.

As soon as Kacchan disappeared into the locker room, the field came alive with the voices of concerned students. Izuku was still struggling to accept what he’d seen as plainly as the rest of them. Kacchan’s quirk had died. He hadn't overused it, the way he’d done as a child when he first began honing his quirk. And while Izuku had heard rumors about quirk-enhancing drugs on the black market, he’d never heard of a drug that could stop a quirk.

But there was more to this fight than the unexpected failure of Kacchan’s quirk. He’d seemed off from the very start, off-balance and sluggish. Kacchan had missed a landing at the very beginning of the match, and it had rattled him, though not enough to account for the next few disastrous minutes. It had been immediately obvious to everyone watching that Kacchan’s head wasn't in the game. But why? Did it have something to do with the medicine Kacchan had mentioned? Was he sick? Terminally ill? The mere thought was horrifying. How could Izuku have known him for so long and not known that Kacchan was apparently very sick? Had he experienced complications because of the previous day’s events? Had Kacchan just learned of his illness?

“Deku,” came a soft whisper from Uraraka, “You know you're jumping to the worst possible conclusion, right?”

Izuku yelped. “Oh, was I thinking out loud?” He scrubbed at the back of his neck sheepishly. “Sorry.”

Her round features softened. “I’m sure you're worried,” she said, “but we all know that Bakugou wouldn't want us to pry,” she smiled weakly, “right?”

Izuku nodded solemnly. “Right.”

She nodded back. “So we’ll do our best to honor his wishes and stop prying.”

Izuku thought he’d probably struggle more with that, as he was well known among his friends for his meddling in their affairs. But then, Katsuki no longer considered him a friend, did he? So should he worry about him? But even if he wasn’t friends with a person, if they were a classmate, or even a complete stranger, if he saw someone in trouble, he couldn’t do nothing. He had to help! He couldn’t stand feeling useless, he needed to do something. But Uraraka was right, there wasn’t really anything he could do, and he didn’t have enough information to try and find out what he might be able to do. All he could do was worry. So he supposed that would be enough, at least until he saw an opportunity to help. He’d have to satisfy himself with that, he decided, begrudgingly following Uraraka back across the field and towards the locker rooms.

Neither of them saw the look of worry etched into Kirishima’s face, the furrow in his brow nearly identical to Izuku’s. He didn't say anything to the students around him, but as he watched Bakugou march across the field, weaving like a drunk man wandering to the train station after a long night in Shinjuku, he vowed to look into his suspicions further. Admittedly, Kirishima was sub-par in most academic areas, and had never excelled at research, observation, note-taking, or really anything that involved books. Still, this wasn’t just homework, this was friendship. With something this important to throw himself into, he was sure he could stay focused. Bakugou was his good friend, and if Kirishima was right about his suspicions, his friend would need the support of a stalwart and loyal friend in the weeks and months to come.

He didn’t yet realize just how much support Bakugou would end up needing, but that was immaterial. Bakugou needed his help, and so, Kirishima would help.

Chapter Text

Immediately after school, Eijirou went straight to the library and found himself a computer, pulling up a search engine. He began by typing “heat trigger alpha”, but all that did was link to what looked like skeevy online adult stores and pornography websites. He considered his next tactic, typed a few more keywords, and tried again. “bad reaction heat trigger alpha sick”. That resulted in a lot of omega heat support sites, several news articles about an uptick in criminal cases where alphas were caught sneaking heat triggers into the drinks or foods of unsuspecting omegas at bars, and a lot of well-meaning articles about “how to be safe” if you were an omega. Which wasn’t really helping him find out what was wrong with Katsuki, and was mostly just upsetting. He couldn’t believe that there were alphas out there doing something so horrible to omegas and, if the article headlines were any indication, these sickos were getting away with it, too!

But he was getting distracted. None of these searches had revealed anything about heat triggers making an alpha sick. He decided to go with a simpler search, reducing his search terms to “heat trigger sick”. This search had several similar news stories to the previous search, but also included some links to medical articles about something called Hypersecretion of the Luteinizing Hormone (HLH). Now, Kirishima knew nothing about hormones, or what a word like hypersecretion might even mean. But he also knew that Bakugou was counting on him to support him and he felt it was only right that he try and figure out what his friend was going through without making him uncomfortable. He fought his way through a few articles, but all he was really getting from it that Luteinizing Hormone was something your body produced that triggered the release of sex hormones.

He typed in “sex hormones” and was about to click on a few more articles when he remembered that his classmates often used the same computer that he was currently using and he should probably delete his internet history immediately. He did that, then went to Wikipedia to consult doctor internet. Sex hormones - which Wikipedia preferred to call sex steroids - weren’t nearly as dirty as they sounded, and were just the kinds of chemicals that animals had in their bodies so they could have sex and babies. He saw words like androgens, estrogens, progestogens, and a bunch of other words that sounded like gibberish to him.

So, then, based on what he’d been reading, it sounded like a heat trigger could mess up the part of your body that controlled sex and babies. Eijirou winced. How terrible! No wonder Bakugou had exploded the thing Mineta brought to class! It could cause a lot of trouble! Being Bakugou, he probably knew a lot more about this stuff than Kirishima, and had immediately understood how bad it would have been for any omegas in the class to be exposed to something like that. But that didn’t explain how Bakugou had gotten so sick from it, especially if he was an alpha, like everyone believed. (Everyone except, perhaps, Eijirou.) Determined to find the answers he was seeking, Kirishima dug back into the the article about HLH, and read it through again, trying his best to wrap his head around the big words. So this disease could be triggered by chemicals, or it could be something that just happened inside the body, usually caused by a kind of brain tumor that was in, on, or near the pituitary gland.

After reading that, Kirishima had to take a break. He closed the window, logged out, and took a lap around the stacks, trying to breathe. There was no way Bakugou was that sick. He couldn’t have a tumor, they would have noticed something sooner, right? He couldn’t be dying, could he? Eijirou could feel his heart pound in his chest, and he couldn’t seem to breathe properly. He grabbed his cell phone and texted Katsuki.  OMG BRO, DO U HAVE CANCER???

He covered his hand with his mouth, watching his phone like it was going to melt away at any moment. After a few minutes, he saw the ellipsis, so he knew Katsuki was typing something back. Then his friend stopped typing. “Oh my god, did he just die?” Kirishima whimpered. Katsuki began typing again, and Eijirou breathed a sigh of relief.

What the hell is wrong with you?

Eijirou breathed a sigh of relief, typing out a quick reply. just worried, bro.

Fucking stop.

With a weak chuckle, Eijirou logged back in, reopened the article, frowned a little, and turned back to his phone. ud tell me if smth was wrong tho?

Why? You’re not my mom.

Eijirou chuckled. “Like you’d tell your mom anything,” he muttered under his breath, sighing and sitting back down at the computer. He reopened the article, reading further. He made it to the symptoms, frowned, and texted Katsuki again.

wut happened yesterday? u get sick?  He eyed the symptoms of HLH. u had a fever, rite? u said u were hot

Bakugo responded quickly. Yeah. But I’m fine now.

Kirishima shook his head slowly. He didn't believe that for a second. Bakugou was avoiding everyone, and he hadn't come back to class after his disastrous performance in gym. He wasn't the type to run off and hide to lick his wounds, he was the type to bluster and pretend it hadn't happened until something set him off. If he hadn't come back, it was because something was very wrong. He narrowed his eyes at his phone and typed again. did u sweat a lot?

Obviously. I was hot.

Katsuki’s tension was palpable, even in text. With a sigh, Eijirou turned back to the computer, skimming the article again for some sort of sign that this weird HLH might be what was really wrong with his friend (and not a deadly, incurable disease).  did u feel extra aggro?  That was one of the symptoms for alphas - increased testosterone, so they would get aggressive and angry and sweat a lot. Which, actually, sounded like Katsuki on a normal day. Eijirou couldn’t imagine what a hulked-out alpha Katsuki would act like. Good god. That was a terrifying mental image.

I felt like someone was punching me in the face repeatedly. Why does it matter?

Headaches weren’t a symptom of HLH. At least, not for alphas. Kirishima frowned thoughtfully. How did doctors do this so easily ? He'd seen Bakugou just that day and couldn't figure out what was wrong with him. He made a face, and turned back to his phone.  did u take something for the fever?

No. It was fine.

Eijirou scowled. So no way to tell if it had been… he shook his head, turning back to the long list of alpha-related HLH symptoms. Oh god.  did u feel… u kno, um… that

Katsuki texted back irritably, I have no idea what you’re talking about.

Eijirou felt his face flush, and he wasn’t even in the same room as Katsuki. like. horny.


Kirishima winced. He probably deserved that. But he wasn’t about to let up now. did u?

I am going to fucking strangle you.

It wasn’t a ‘no’. Kirishima stared at the HLH symptoms. He couldn’t think of anything else. Instead, he scrolled down to the treatment section, and clicked through to see what kinds of treatments there were, and what they did. He began reading through it, stopping cold when he saw the first few side effects listed. “Oh my god,” he whispered. Dizziness. Nausea. Vomiting. Muscle weakness. Temporary blindness. He turned back to his phone, fingers trembling so badly he had to retype the message twice. r u sure ur ok?


Eijirou chuckled a little at that, but he took a stab in the dark, taking into consideration how poor Katsuki’s performance had been.  hows ur quirk?

It’s fine. Don’t you have fucking homework? Stop asking stupid questions.

Somehow, Kirishima didn’t believe that. With a sigh, he turned back to the article. Maybe his friend was in even deeper trouble than he’d thought…

 Katsuki scowled at his phone, throwing it at the wall and swearing creatively. “Fuck this,” he snarled, laying back on his bed and staring at his hand, willing an explosion, some sparks, anything, to appear. Nothing. He knew what it was, too. For the first time he could remember, his palms were dry. His skin, normally smooth, was almost chapped. He wasn’t excreting anything, so he couldn’t explode anything. He had nothing now. He couldn’t use his quirk, couldn’t fight, couldn’t even walk a straight line or stand up without feeling like he was moments away from puking.

This was all Mineta’s fault. He was going to murder that creep. ...once he could walk five feet without hurling his guts or falling over. He scowled at the ceiling of his dorm room like it was a personal affront to be looking at it. Despite what he’d believed to be the solution, his symptoms had not improved after taking his medicine, and Recovery Girl had kept him flat on his back in her office behind a curtain for the rest of the day. He was going stir crazy.

Rolling over furiously, Katsuki screwed his eyes shut and breathed through the waves of nausea. He stared at his palms, willing them to sweat, but somehow, the finely-tuned control over his body that he’d mastered through years of practice had completely failed him, and he couldn't do what he'd always been able to do. A thought occurred to him, then, that this was somehow punishment for something, that he’d been a villain in his past life or something. Or maybe something he’d done in this life. Katsuki never really thought much about how other people felt about anything, but he had to admit that it stung to think of himself as, well, a quirkless loser. But that's what he was, and so he would remain until his body recovered from his first heat. That's what he kept telling himself, that this was temporary.

He rolled back on his back, screwing up his face as he scowled at the ceiling. If it was temporary, why did he need to take so much medicine? Why couldn't he just power through a bad heat triggered by some nasty chemicals? Why couldn't he just… just get over this? Why him? It wasn't… fair. But then, he thought glumly to himself, people aren't born equal. Sometimes you just have to play the hand life dealt you.

Fuck that, Katsuki decided sullenly. He’d just have to stack the deck. With a grimace, he rolled out of bed and staggered across the room to where his discarded phone lay. He managed to not fall over while picking it up, and resisted collapsing into his bed, forcing himself to sit down before lying down, just to prove to himself that he could still do it.

Phone in hand, he got comfortable, then opened an internet browser, searching for “heat complications”, adding the phrase “glandular disorder” after a moment. The doctor may have been a smug bastard but he probably at least knew the right terminology to use. Katsuki began to examine the list of results on his phone, scrolling past the obvious quacks and unhelpful articles. He found an omega hyper-heat support page (he didn't think he had anything bad enough to be called a hyper heat but it sounded close enough), and found several comment threads that seemed promising. He began skimming the threads to find more information about what was happening to his body, and how he could deal with it on his own. He was certain that there had to be a better way of dealing with his heat than taking a medication that was blocking his quirk, too.

Unfortunately, modern medicine seemed unconcerned with his plight, and was convinced that if his heats were that bad, he just needed to suck it up and find a nice alpha to take care of him when he felt sick. The mere thought of it made Katsuki nauseous. He wasn't going to just go out and throw himself on the mercy of some asshole who happened to be an alpha. Katsuki didn't want to deal with that, or anything that might come along with it. Hell, he’d heard horror stories about male omegas getting pregnant, and while he was fairly certain that was all old wives tales, it was nonetheless thoroughly creepy. Not to mention that, while omegas were already statistically the rarest of the secondary genders, male omegas made up an even smaller subset of that already small group. They were often seen as less manly (though there was only a small correlation between masculinity and the alpha’s dominant characteristic, people still tended to associate the two concepts), and more emotional, clingy, and needy than even female omegas. Because sexism hurts everyone when being girly is seen as a bad thing. Personally, Bakugou didn't know what the hell people’s problem was, his mom was the most badass alpha there was - besides pro heroes, obviously - and she wasn't a man. Bakugou had decided from a young age that if his mom could be a badass woman who took no shit, then he would be a badass omega who took no shit, and he held himself to the standard of performance he imagined was the pro hero ideal.

Except, when he declared himself the best or demanded his opponents face him squarely and always fight with their best foot forward, he was seen as cruel and demanding and aggressive. He didn't think it was aggressive to demand the respect of his peers when he’d damn well earned it, so what the fuck was wrong with everyone else? Convulsively, Katsuki turned off his phone, almost chucking it back across the room before reigning himself in at the last second. He scowled at it, disappointed in his options - no quirk, or no bodily autonomy? Which was worse? He wasn’t sure. With a sigh, Katsuki reached out to his desk, which sat next to his bed, picking up his prescription bottle full of small white pills. He lifted it slowly, eyeing it with distrust. He just wasn't sure...

Chapter Text

When Kirishima made his way into the dorms that evening he looked distraught. He’d spent hours researching the different ways that ruts and heats could go wrong and he was no closer to finding out what was wrong with Bakugou, though he was now half-convinced that everyone he knew might be slowly dying of horrible diseases you could self-diagnose on the internet.

“What the hell happened to you?” Kaminari demanded upon spying the thoroughly wrung-out redhead. “Are you getting sick too?”

Oh god. “We might all be sick,” Kirishima intoned solemnly, looking ready to accept the news that Bakugou’s funeral was scheduled for next week.

Kaminari blanched. “Really? Damn!” he looked worried. A look of confusion crossed his face then. “How do you know for sure that we're all sick?” he demanded, “I feel perfectly healthy!”

Kirishima shook his head dejectedly, “I don't know, man, I was trying to figure out what's wrong with Bakugou and he was being all tight-lipped and now I think he’s dying.”

From across the room, Ashido snapped her book shut. “Now that's just ridiculous,” she declared. “He might be feeling the effects of his heat a bit more strongly because of the trigger and this being his first presentation, but he definitely isn't dying… what?” she glanced around slowly, noting that everyone in the vicinity had stopped what they were doing to stare at her, mouths agape like a school of bewildered guppies.

“But… but Bakugou isn't an omega,” Kirishima said slowly, though the wheels in his head had begun spinning furiously.

Others in the room nodded in agreement. Ashido eyed them all and scoffed lightly, turning back to her book as she said, “Take it from me, he’s hella omega.”

“That doesn't even make sense, though!” Kaminari protested. “He’s so, so, so… Bakugou!”

Ashido raised an eyebrow, but didn't rise to the challenge. She was, however, holding her book upside down, so perhaps she wasn't quite as unaffected by the conversation as she’d like people to assume.

Kirishima laughed nervously. “Yeah, besides, even if he was an omega, that wouldn't explain why his quirk was going weird, right?”

“I don't know, man,” Kaminari said weakly, suddenly a lot more resigned-sounding than Kirishima thought the situation warranted, “I’ve heard that alphas can force omegas to submit through the force of their will alone.”

Kirishima scowled, “Even so, that doesn't explain how Bakugou-”

“We’d all smell the submission on any omega that got overpowered to that extent, not to mention the alpha himself would reek of power if he were really whipping out those alpha commands,” Jirou interrupted, her nonchalance sounding a little too forced. Kirishima found himself wondering why she was so invested in the discussion that she had to feign disinterest.

“That's a good point,” Kirishima agreed, “If anyone had tried to use an alpha command on Bakugou, we all would have smelled it, right?”

“Not necessarily, in a fight, alphas have a much easier time forcing the aggression out of an omega,” Ashido spoke up again, apparently some sort of resident expert on omegas. “It doesn't leave a scent trace for long at all, and since Bakugou was out on the field when his quirk stopped…” everyone was staring at Todoroki now.

With a sigh, the young man glanced up from his homework, showing little interest in actively joining the conversation. “Interesting theory,” he said blandly, turning back to his homework as he added, “I’m not an alpha, though.”

Time slowed as everyone in the room turned to look at him. “You're not?” Kirishima demanded.

Todoroki looked up from his note-taking, feeling the eyes of the room on him. “Of course not.” He said this calmly, almost passively. “I’m a beta.”

Everyone exchanged looks. “Really?” Kaminari demanded. “Prove it!”

“No,” Todoroki answered simply, going back to his notes, “and stop talking about Bakugou behind his back. Aren't you supposed to be his friends?”

Kirishima, Kaminari, and Ashido exchanged guilty looks. “Yeah,” Kirishima admitted after a moment. “We are. And we will, I guess. Stop, I mean.” He wandered across the room and grabbed a magazine sitting on the coffee table, opening it to a random page and staring at it unseeingly. Was Bakugou really an omega, like Ashido seemed to think? Was his quirk loss related to his secondary gender, or something else? Was he going to be okay? He wished he could do something to help…

He closed the magazine, setting it down and turning to Ashido, hoping she might know more than she was letting on. “Hey, Mina,” he began, trying for the friendly approach.

“Yes, Eijirou?” Ashido glanced at him curiously.

Shit. He hadn't had a plan that lasted beyond “Talk to Ashido”. “I'm. Uh. I wonder if you know anything else about omegas who need medicine,” he said slowly.

“There are lots of kinds of medicines for omegas,” Ashido said, setting her book down. “I thought you were an alpha?”

Kirishima nodded slowly, failing to see where this was headed. “Yeah, so?”

Ashido glowered at him. “Were you planning on ever mating an omega?”

Kirishima squeaked nervously, taken aback by her frankness. “I guess,” he said weakly, “why?”

Ashido sighed. “If you're going to mate an omega you should know about omega biology and needs so you can treat them right and care for them, yes?”

Kirishima felt his face flush with embarrassment. Why was Mina always one step ahead of him? She was such a good person, no wonder she was training to be a hero! “Right,” Kirishima agreed.

Ashido stared at him expectantly, her shoulders drooping a bit more with each consecutive second of silence. “Right, guess we’ll start at the beginning, then,” she said, turning to fully face Eijirou. “You at least know how heats work, yes?”

“Uh… they make omegas super horny?” Kirishima guessed, feeling his face begin to burn.

Ashido stared at him for a long, awkward span of several silent seconds. “Oh my god, did you even pay attention in health class?”

“No?” Kirishima squeaked, sensing this was not the right answer.

Ashido sighed. “Omegas go into heat to attract a mate.”

Kirishima nodded. “Okay. And?”

Her black eyes were staring at him, probably a little on the judgemental side. Kirishima didn't begrudge her the judgement, because for all his googling he hadn't thought to investigate the ways that omegas and alphas actually lived out a reproductive cycle. Ashido continued to explain an omega heat to Kirishima, “The scent they produce-”

“Oh yeah, triggers a rut in alphas!” Kirishima said excitedly. He knew that part.

Ashido stared at him until he had the decency to apologize for interrupting her, and then continued. “Omegas produce a scent that calls alphas to them. That same biological process also triggers a reaction, making them more fertile. It can make them tire more easily, and it relaxes them, which makes it harder for them to put up a fight. Often, it raises their core body temperature by a degree or two, which may cause a little discomfort. In some cases, a fever reducer might help keep the temperature low, but for most omegas it won't do anything and they just have to put up with it.”

Kirishima frowned. He’d never heard that heats made omegas literally overheat. His mind strayed back to Bakugou, tugging at his gym collar, demanding to know why it was so hot in the locker room. His stomach lurched, his heart thumping nervously in his chest. “Oh my god,” he said weakly, turning to look at Ashido. “He really is an omega.”

Ashido scowled. “Omegas don’t usually get -” she made a face, “horny - ahem - until later in their heat, because that is caused by the hormones triggered by alpha pheromones that are produced by an alpha in rut.” She stared hard at Kirishima. “That’s why an alpha in rut can have any omega he wants - even when they're not in heat, omegas are biologically programmed to respond favorably to an alpha’s advances.” She scowled. “That's why there's so much confusion around the topic of omega rape - how do you prove rape if you seem willing? Even if you're screaming no in your head, your body could betray you anyway and make it seem like you're interested or enjoying something that you really aren't.” She scowled, a dark look of righteous fury flashing across her features. Kirishima had the strangest feeling that she was speaking from experience, somehow.

“So then why does everyone talk about omegas in heat using, ehrm, y'know, ...that stuff?” Kirishima felt his face burning.

“You mean sex toys?” Ashido asked blandly.

Kirishima choked. “Right, yeah, those.”

“Alpha power fantasy,” Ashido answered with brutal honesty, “we like to think that omegas are just sex-starved creatures craving the attention of an alpha, because it makes us feel magnanimous when we’re taking advantage of them.”

Kirishima felt a little sick. “Oh. Damn.”

“The best way for an omega to get through a heat is to spend it with an alpha, obviously,” Ashido said, “it's biological hardwiring. But it’s not a life or death situation. There are plenty of suppressants out there, and while some omegas might happen to use toys while in heat, they're almost as likely to use them when not in heat.”

Kirishima nodded seriously, then paused. “What about hyper-heat?” he asked hesitantly.

Ashido whirled on him, her dark eyes boring into him. “What about hyper-heat?” she parroted back, an edge to her tone that hadn't been there before.

“Aren't those dangerous?” Kirishima asked weakly. “The heat goes overboard, and then even suppressants aren't enough to help an omega.”

Ashido stared at him for a long moment. “That's an extremely rare condition.” She narrowed her eyes at Kirishima. “Bakugou’s definitely not-”

“But what if the heat trigger sent him into hyper-heat?” Kirishima protested, louder than he’d intended.

Everyone in the room stopped talking and turned to look at Kirishima. He looked back over the couch and waved to the room, smiling weakly. The smile dropped from his face when he saw Bakugou himself, hovering in the doorway, his pale features contorted into a mask of fury.

“Shit,” Kirishima whispered, standing up, eyes only for Bakugou. “I’m sorry,” he started, but Bakugou had already spun on his heel, walking away from the communal living space. “Wait!” Kirishima called, vaulting over the back of the couch and running to the door. “Bakugou! Bro! Hold up!”

Chapter Text

Kirishima made it to the door in record time, spotting his friend the moment he entered the hall. Bakugou was storming away from the common area at an impressive clip, but he was staggering like a drunkard, one hand pressed firmly to the wall as he went.

“Bakugou!” Kirishima called, hurrying after him, “Wait! I didn't mean - I’m sorry I -”

“Fuck off,” his friend snarled, punching open the door to the stairs, struggling up the steps, listing to one side as he climbed. Bakugou seemed even worse than he had on the training field, and Kirishima felt that it was his fault somehow, even though it didn't make sense logically.

Kirishima followed Bakugou up the stairs, taking the steps two at a time until he reached his friend. “I’m sorry,” he said again, resisting the urge to grab Bakugou’s shoulder and make him stop, if only because he was half-afraid any sort of move on his part might unbalance his friend enough to send the blonde tumbling backwards down the stairs.“We shouldn't have been talking about you behind your back.”

Apparently he’d said the right thing, because Bakugou stopped, one hand on the wall, and fixed his bloodshot eyes on Kirishima. “You got that right, asshole.” He started climbing again, so maybe Kirishima’s line hadn’t worked quite as well as he thought.

Kirishima followed Bakugou, trying again. “I deserved that,” he admitted, matching his pace to meet Bakugou’s shaky ascension.“We're just worried about you!” This time, he risked laying a hand on Bakugou’s shoulder.

“Don't,” Bakugou spat, tugging away from Kirishima’s touch, leaning against the wall, face white with rage. “It's my business, not - it’s just… look, none of this is any of your fucking business! So stop fucking worrying about shit.

Kirishima found himself frowning. “But you’re my friend.”

“So?” Bakugou looked even more ready to explode than usual. “You can be someone’s friend without fucking losing your shit over things that have nothing to do with you.”

“If it affects you it affects us!” Kirishima argued. “That’s what being friends is about!”

“That is not what being friends is about,” Bakugou shot back, an inner flame dancing in his crimson eyes. “Friends don’t turn into gibbering nail-biters who cry about being worried when a person close to them is struggling - they tell their friend to get his shit together and fight back.”

“Is this even something you can fight?” Kirishima retorted, shoving at Bakugou’s shoulders, suddenly furious. “You won’t even tell us what it is, how are we supposed to know if it’s something you can fight?”

“Well it’s not as bad as fucking cancer,” Katsuki snarled, teeth flashing as his mouth twisted in a derisive snarl. “And people fight cancer all the goddamn time.” He shrugged off Kirishima’s grip with a low growl and a glower.

“Is it a disease, then?” Kirishima asked, not sure what to do with his hands, so he just wrung them together anxiously.

“Not in the technical sense,” Bakugou answered, rolling his eyes.

“Then, are you...?” Kirishima trailed off, coughed awkwardly, and tried again. “Are you in heat? Is it a hyper-heat?”

Bakugou’s eyes bulged like his fury might pop them clean out of their sockets. Then it was like something inside him snapped, and he went limp, as if all this time he’d just been held taut by a fraying cord that had finally given way. He sank down onto the steps, wrapping his arms around his knees in a picture of defeat so unlike Bakugou that it made Kirishima’s chest ache. “Yeah,” the boy said, eyes cloaked behind a curtain of blonde hair. He mumbled into his knees, “the doctor has me on some hardcore suppressants that are fucking me up bad.”

Kirishima sat down next to Bakugou. “Shit,” he said weakly, looking at the other boy’s bowed head, trying to think of something to say, to somehow fix this. “Why don't you just… you know, try to power through the heat?”

Katsuki turned to him with a look of pure venom. “If I could, I wouldn't be on the fucking meds.”

Kirishima winced. “Right. My bad.” He nudged Bakugou with his shoulder. “Hey, at least heats only last a few days, right?” he grinned. “I’m sure you'll be fine in no time!” He was already mentally patting himself on the back when he realized Bakugou didn't look happy at all. In fact, he looked even worse, like he was a firecracker about to explode.

Bakugou sighed heavily, staring at the palms of his hands for a moment before turning back to Kirishima, scarlet eyes boring into the redhead. “That's a few days every fucking month,” he pointed out. “That tallies up fast.”

Kirishima was floundering for something positive to say, and Bakugou really wasn't helping him. “At least Mineta’s been expelled, so you won't have to deal with that again,” he pointed out, smiling encouragingly at his friend. “I’m sure things will get better soon!”

Bakugou turned his gaze to the floor, shoulders slumped. There were dark circles under his eyes. In a tired voice, he murmured, “I wouldn't count on it.” He turned to Kirishima. “The doctor wasn't sure if this was triggered, or if it's just me.” He turned back to his hands, scrutinizing them as if the vast mysteries of the universe were contained in the whorls on his fingertips. “If it's me, I… I can't accept it,” he said slowly, curling his hands into fists. “I won't allow myself to become useless, a quirkless loser.” He looked at Kirishima, eyes wide, blood-red, and deeper than a chasm, like somewhere behind them Katsuki was drowning in the reality of his situation. “You understand my meaning, don't you?”

Kirishima wasn't sure he did, and had a feeling he didn't want to. “I’m sure they'll find a way for you to continue your studies,” he tried to say reassuringly, his heart clogging his throat so the words came out strangled.

Katsuki turned on him then, grabbing his shoulders, fingers digging in like claws. “And if they don't?” he spat. “I can't - I won’t be like this, I refuse!”

Kirishima frowned a little. “Bakugou, if this doesn't get better… what are you going to do?” he asked quietly.

A shadow passed over Katsuki’s face. “I’ll do what I have to.”

Kirishima didn't like the sound of that. “What do you have to do? Are you going to give up your dream?”

Katsuki looked at Kirishima as if he’d grown a second head. “Fuck no. I’ll make the doctors give me something better. Something that won't stop my sweat.”

Kirishima felt a flashbulb go off in his head. “Wait, that's why your quirk isn't working?”

Bakugou frowned. “Of course. Why did you think it wasn't working?”

Kirishima realized he hadn't actually thought that far ahead. “Uh…”

Bakugou smirked at him. “Typical,” he said, pulling himself to his feet. Kirishima jumped up too, offering Bakugou a hand, which the blonde batted aside, beginning the climb up the stairs again.

Kirishima climbed with him. “Are you okay?” he asked hesitantly.

Bakugou fixed him with a look of disgust. “Fine. Now go back to your fucking gossip time with Ashido or whatever.”

Kirishima wanted to protest that he hadn’t been gossiping with Ashido, he’d been… commiserating? Getting involved in a small-group worry session? It still all translated to ‘gossip time’ at its core, so with a sigh, he dropped his head and nodded. “Right. Sorry about that.”

Bakugou sighed, slowing to a stop again, leaning against the wall to eye Kirishima critically. “You already said that,” he said. “Stop fucking apologizing for everything. You act like I’m going to break if some damn side characters start talking shit about me.”

Kirishima couldn’t help protesting at that. “We weren’t saying anything bad!” he exclaimed. “We weren’t trying to hurt your reputation or anything, honest! We were just worried!”

“Bullshit,” Bakugou told him, eyes burning into Kirishima with laser-like intensity. “If you were worried about me, you could have come and knocked on my fucking door and asked me what was wrong like a man. Instead, you went and whined to Ashido in a public area where everyone could hear you.”

“You wouldn’t tell me what was wrong, though!” Kirishima protested. “I tried texting you!”

Bakugou just stared at him coldly. When it became obvious that Kirishima believed this to be a compelling argument, he sighed again. “Jeez, for a guy who seems so hung up on doing things the manly way, you sure don’t know how to talk to someone like a man.”

Kirishima sputtered in protest, but Bakugou held up a hand, cutting him off. “No,” he said, “Now it’s time for you to listen, asshole.” He poked a finger in the redhead’s chest as he began. “When you have a question about me, you fucking ask me. Face to face. None of this beat-around-the-fucking-bush nonsense. No asinine texts that ask open-ended questions. No freaking out about whether I might have cancer or some other bullshit.” He folded his arms. “Don’t be a fucking child and just talk to me. Fuck.”

Kirishima nodded slowly. “You’re right. I’m sor-”

Bakugou cleared his throat pointedly with a look that dared him to continue.

“I'm... glad we had this talk,” he quickly revised his sentence. A thought came to him. “I’m guessing you don’t want us to keep talking about you, then?”

Bakugou just stared at him levelly. “What do you think, rocks-for-brains?”

Kirishima winced. “Right, I’ll keep it between us.” He frowned a little. “Take care of yourself, okay? And text me or something, if you need anything. Because we’re friends.”

Bakugou waved his concern aside like a pesky fly. “I’m fine,” he said, turning to head back up the stairs, ignoring the way Kirishima gasped when his knee nearly buckled on the next step. “I’m fine,” he said again, louder, like it wasn't Kirishima he was trying to convince, but himself.

Kirishima nodded, watching him go for a moment longer before turning and heading back down to the common area, his mind awhirl with revelation... and remorse.

Chapter Text

When Kirishima made it back downstairs, only a few minutes after he’d chased after Bakugou, it seemed like a few more people had wandered in and the conversation had shifted from Bakugou to upcoming homework assignments and other “safe” topics. He glanced around the room, his gaze landing on Ashido, who was still sitting exactly where he’d left her. He didn't think anything of it at first, until he saw her fingertips trembling against the pages of her book.

Kirishima decided maybe Ashido could at least use some reassurance that Bakugou didn't hate them, and he could ask Ashido to stop talking about Bakugou behind his back, even though technically it was his fault for bringing it up in the first place. Maybe she’d even agree to help him keep his big mouth shut about Katsuki if he got overexcited and started blabbing again.

He plopped down on the couch next to Ashido. “Hey,” he said by way of greeting, “I’m back.”

Ashido glanced at him with wide eyes. “Was he really mad?”

Kirishima shrugged lightly. “No more than I deserved,” he said, finding himself suddenly unable to look her in the eye. “Sorry I dragged you into it,” he apologized.

“No, I’m sorry,” Ashido countered, turning to face him. “I should have known better.”

Kirishima smiled weakly. “We both should have.” The two of them sat silent for a moment, contemplating what had transpired. Finally, Kirishima turned back to Ashido, not sure how to put into words what he wanted to say. What ended up coming out was, “So, uh… No more talking about friends behind their backs, am I right?”

Ashido smiled back. “Sounds like a plan.”

Bakugou didn't make it to class the next morning, a fact that did not go unnoticed, especially considering how hard he’d fought to be in class the day before. Despite his adamant refusal to discuss Bakugou’s current situation, Kirishima nonetheless found himself the target of a thousand questions. Everyone was worried about the explosion-quirk user, and Kirishima had been the last person seen with him. This patently made him something of an expert on Bakugou.

For his part, Kirishima was just trying to do right by his bro and keep personal details private, which didn't go over too well with his classmates.

“Come on, man,” Kaminari wheedled, “I’m just worried about him!”

“We’re all worried,” Kirishima countered. “If he's not in class, it’s for a good reason.”

“Is it true?” the blonde asked him conspiratorially, though at a volume that was more conspicuous than not. “Is Bakugou really an omega?”

After yesterday, Kirishima couldn't help but see the actions of himself and his friends in a new light, and it wasn't pretty. Was this the kind of behavior that usually bothered Bakugou when they hung out? Kirishima was beginning to see why. There was no way the blonde’s question hadn't been overheard by everyone in the classroom, yet he insisted on acting as if this was merely a conversation between the two of them. Maybe it wasn't an act - maybe he really wasn't aware of how much his voice carried. Kirishima felt a sudden onslaught of delayed embarrassment for all the times he'd said dumb shit and people had probably heard every word, all because he thought he’d been speaking in a discreet voice. He made a mental note to stop doing that. Some conversations were better had with the party in question, in a private space. Class was not a private space.

Already he could hear the room reacting to Kaminari’s question, people whispering about Bakugou being an omega, and Kirishima just wanted to slam his face down on his desk. He hated keeping secrets, but this wasn't his to tell. “You shouldn't ask me questions I can't answer,” Kirishima told Kaminari seriously. “It’s not my information to give.”

“So you know, you just won't tell us?” Kaminari demanded, sounding upset.

Kirishima guessed it could sound bad, when you put it that way. “I wouldn't tell you even if I did know because I-”

Kaminari turned away with a huff. “Ashido, what do you think?”

Ashido sighed, looking as guilty as Kirishima felt. “I think you should talk to Bakugou.”

Kaminari whined. “But you talked about him last night!”

Ashido glowered at him. “Yeah, and I feel terrible about that, thanks for the reminder.”

“You were talking about Kacchan?” Midoriya piped up weakly, as if he knew he shouldn't contribute to the conversation but couldn't seem to stop himself.

“Yeah, they were going on about how it was obvious that he's an omega, but now because Bakugou heard them talking about him, suddenly they can't anymore?” Kaminari scowled. “It's hypocritical.”

“I like to think of it as self-awareness,” Ashido shot back. “I realize that I shouldn't have done that, but I can't change my past behavior, only my future choices, and I choose to not talk about a friend behind his back.”

“A noble decision,” Iida piped up, approval in his tone, before his voice sharpened a little. “So if everyone could return to their seats in an orderly fashion -”

It was at this point that Mister Aizawa burst into the classroom, calling everyone to order. “Before you get the chance to ask, I’ve been informed that Bakugou is fine , however, he will not be in class today. Can I get a volunteer to take notes for him?”

A few students raised their hands hesitantly, including Kirishima and Ashido.  

“Good, Yaoyorozu, I’ll have you do that,” Aizawa decided, and promptly began their class lecture.

Kirishima tried not to feel insulted due to being passed over by their homeroom teacher. He knew he was no top student, but it still stung that Aizawa would pass him over even though he and Bakugou were bros. Then again, Kirishima realized, whenever he and Bakugou studied together, it would invariably devolve into Bakugou lecturing him about his poor study habits before demanding Kirishima’s undivided attention while he explained whatever had Kirishima confused in excruciating detail, using his personal class notes as a reference because Kirishima’s own were consistently a disaster.

Kirishima was a very kinesthetic learner, so his notes would sometimes take on odd shapes, or he might cluster related concepts in a corner together and separate unrelated concepts. At times Kirishima would even shift handwriting styles to try and give the notes more “character”. Bakugou would always wrinkle his nose at the very idea, his own notes organized in perfectly straight columns with the occasional bulleted list, chart, or table to mix things up. Hard to believe someone who seemed so chaotic and aggressive on the outside could still take take detailed notes like a deeply studious person. Had he mentioned this to Bakugou, his friend probably would have flipped him the bird with both hands before reminding him that he's the best, that’s why. Kirishima glanced at the door, almost longingly. Bakugou had looked frankly awful yesterday. He hoped he was feeling better today. Of course, if he were really feeling better he wouldn't have stayed home...

Kaminari elbowed Kirishima, giving him a wide-eyed look that seemed to say “pay attention!” And that, Kirishima realized despondently, was the proof of why Aizawa hadn't asked him to take notes. He had no idea what the teacher was talking about at this point, so he didn't even bother taking notes, just scribbling down the occasional word as Aizawa droned on.

Finally, after what felt like forever, the school day ended. Yaoyorozu disappeared as soon as class ended, leaving half her things sitting at her desk. She returned a few minutes later to collect her things.

Still worried, Kirishima took his sweet time gathering up his own belongings. As he headed for the classroom door, Yaoyorozu intercepted him. “I can't take these notes up to the boys’ floors,” she explained, handing him a bundle of notes, still warm from the photocopier. “Can you deliver these to Bakugou?”

Kirishima nodded and accepted the stack of paper. Yaoyorozu’s notes looked very similar to the kinds of notes Bakugou might take. Kirishima was sure he’d approve. Or at least not gripe about them. “Thanks,” he told Yaoyorozu.

“Tell him we all hope he feels better soon,” Yaoyorozu added, smiling weakly.

“I will,” Kirishima promised. He wasn't sure Bakugou would necessarily appreciate the sentiment, though. Still, it wouldn't kill his explosive friend to hear that people were thinking fondly of him, even if he insisted on seeing it as pity. With a sigh, Kirishima shifted the weight of his backpack a little, and headed for the dorms.

Chapter Text

Midoriya Izuku was reeling. How had he not known that Kacchan was an omega? They’d been childhood friends, how had it never come up? Then again, Midoriya couldn’t remember ever explicitly telling Kacchan where he lay on the spectrum, either. He’d just assumed that Katsuki knew, assumed that his mother would have cautioned him more if she’d known - had she known? Was Kacchan’s secondary gender a secret shame of the Bakugou household? He didn’t think so, though now that he thought about it, he wondered if Kacchan disliked being reminded of his secondary gender. I mean, no one was arguing that Mineta had crossed a line with his heat trigger, and of course Kacchan would hate to let a “little thing” like physical limitations and biology come between him and his ambitions.

Still, Izuku thought, staring blankly at the same page of his math homework, scribbling down notes in his scratch paper that had nothing to do with pre-calculus, Kacchan had been affected by his biology, in spite of his dogged insistence that nothing was wrong. He closed his eyes momentarily. He’d been blindsided by the information. For the longest time, Midoriya had seen Kacchan as a top alpha: he was powerful, aggressive, single-minded, cunning, and ruthless. To find out that after all that he was really an omega… well, frankly, it had turned his world upside-down.

Not that this was a bad thing, necessarily, it simply meant that Izuku found himself rethinking countless interactions he’d had with his childhood friend, viewed through a different lens. Before finding out about Kacchan’s secondary gender, Midoriya had always assumed that he’d resented him simply because Midoriya was a terrible excuse for an alpha. He thought that Kacchan viewed him as weak - which, well, he definitely did - and somehow lacking in the sheer intimidation factor that seemed to come naturally to an “alpha” like Kacchan.

Oh how wrong he’d been. Kacchan hadn’t hated him because of his weakness, he’d hated him because he was squandering the very thing that Kacchan longed for more than anything. Izuku had been quirkless, and there were no quirkless heroes. Kacchan was an omega, and there were no omega heroes. In his own way, Kacchan had been lashing out against the same message he was constantly recieving from the world around him, and unable to find a suitable response in his own mind, he’d sought to crush Midoriya with the same depressing “truth” that he’d found himself saddled with: that he would never become a pro hero.

Except. Izuku hadn’t given up, and neither had Kacchan. It didn’t make sense. Wouldn’t Kacchan admire Midoriya more, for becoming a hero despite all the people in his life telling him it was impossible? Shouldn’t Izuku’s success have felt like a success to Kacchan, too? If quirkless Midoriya could become a hero, then couldn’t omega Kacchan…

Izuku felt his stomach curl into a knot as realization settled onto him. Midoriya wasn’t quirkless anymore, but Kacchan was still an omega. He’d beaten the system, and Kacchan was still trapped, betrayed by the body he’d been born into. Suddenly, the frustration and anger made too much sense: of course Kacchan hated Izuku, Izuku had been like him, and yet so unlike him. As children their dreams had both been dashed by reality, and yet neither had given up. But where Izuku wore his heart on his sleeve, Kacchan had concealed his weakness, built up wall after wall around himself.

When Kacchan had called him useless, had he really been speaking about Izuku, or about himself?

Shaking his head, Izuku stared blankly at the scribbled words he’d written on his paper before quickly scratching them out and balling up the paper. He had no right to be writing that sort of thing down, anyway. It wasn’t really his business.

With a sigh, he copied down question seven again, and began working, though he wasn’t really paying much attention to the assignment. His mind was still whirling, caught up in the realization that Kacchan must have been suffering for a long time, suffering like Izuku had when he’d been told by the doctors that he could never become a hero. Both of them had been born into a body not built for hero work, but now only one of them was suffering the consequences.

For all this time, Kacchan had been suffering alone.

Midoriya pressed his lips together in a thin line, returning his focus to the math homework, his eyebrows drawing together and creasing his forehead as he concentrated. At least Kacchan had friends, right? Maybe this was a good thing. Maybe Kacchan wouldn’t have to suffer alone anymore.

He dropped his head on the desk and sighed. Although he’d not had any friends in middle school, he suspected that friends wouldn’t have made him feel any better about his dream. No matter how many encouraging things his mother said to him, he could tell from the sad look in her eyes that she didn't believe it, that she wanted him to stop hurting, that she felt sorry for him and lied to try and make him feel better. It had stung, almost more than a straight answer from the doctors had.

No wonder Kacchan hated to be pitied. Who wouldn't, when they knew it was a grim look into their future as “the poor omega trying to be a hero”?

Midoriya could understand that emotion better, now that he had a better understanding of why Katsuki hated to be pitied.  Izuku didn’t really like to see that look in someone’s gaze either. Still, it didn’t stop him from feeling sorry for Kacchan. Not because Kacchan was an omega - Izuku had no doubt that Kacchan would become a pro hero regardless, he just would - but because he realized that Kacchan had been hurting in secrecy and silence for a long, long time.

Keeping such a painful secret had to have been difficult for him.

He hoped that Kacchan would see his friends’ concern for what it was - not an acknowledgement of his weakness, but an admiration of his strength and ambition. Kacchan wasn’t weak. He was volatile and dauntless and cruel and brimming with overconfidence. He was an omega. Above all that, Izuku was certain that Bakugou Katsuki was destined for greatness. He was a hero. He was a hero more than he was anything else, that's just who Kacchan was.

Another paragraph stared up at him where his math homework should have been. With a loud grumble, Midoriya scratched it out, crumpling another sheet of paper and tossing it to the floor. He needed to stop thinking about Kacchan and just do his homework.

If only it were really that simple...

Chapter Text

Swallowing hard, Kirishima lifted a hand to knock on Bakugou’s door. He didn't know why, but it felt weird, somehow, to be bothering him. Bakugou was a very private person, and Eijirou couldn't actually remember a time he’d been invited to Bakugou’s room. Knowing that his friend was in heat just on the other side of a flimsy wooden door felt… weird, maybe a little exciting… but mostly it felt incredibly awkward. Even after Ashido had been so insistent that omegas don't get horny until after coming in contact with an alpha in rut, Kirishima still found himself imagining Bakugou doing lewd things on the other side of that door.

He really was a terrible friend, he realized with a flush of shame. Bakugou wouldn't want Kirishima to think of him that way, wouldn't want him to imagine his pale face flushed pink, shiny with sweat. Kirishima shut his eyes, trying to block out the mental image but it was right there and as much as it was forbidden, there was something tempting about it.

Kirishima knocked convulsively, if only to convince himself that Bakugou was probably just sleeping. He leaned in to the door, listening for some sign of life. He heard the light droning noise of a fan, and an aggravated groan.

The door creaked open a moment later, and Eijirou staggered back, his nose assaulted by the sudden overwhelming smell of Katsuki emanating from the room. He realized, then, that the smell had been in the hall, too, though much fainter. Now Katsuki was glaring up at him blearily, leaning against the doorframe and damn his shirt was clinging to his body. Not that Kirishima hadn't seen him in tight-fitting clothes before, but the smell seemed to be clouding his mind. Had Bakugou always looked so sinuous? So sensual? He wanted to touch him. He wanted-

“The fuck do you want, shitty hair?” Katsuki demanded in a gruff tone. His arms and legs were shaking, and Kirishima realized the air in the room was freezing cold. Katsuki seemed to be blasting the AC, but he was sweating? He was sweating.

“You're sweating,” Kirishima said, the copied notes dangling weakly in his grip.

Katsuki sneered, flexing the hand dangling by his side, a few sparks crackling in his palm. “I halved the suppressant dose.”

Kirishima frowned. “Is that safe?” he asked, feeling concern bubbling up in his chest.

Bakugou scowled at him. “Fuck you.” He sighed then, sagging against the door frame. “I’ll have to go back to the regular amount,” he said after a moment. “The fever is too high to keep this up.” He wiped at a bead of sweat trickling down his face. “Plus, this is too much sweat. No matter what, I'm stuck with one of two extremes.” He wobbled unsteadily, squinting at Kirishima with sudden suspicion. “Why are you here? Checking up on me?”

“Yaoyorozu copied her notes for you,” Kirishima explained quickly, thrusting them in Bakugou’s direction.

Bakugou glanced at them, looked back at Kirishima, shrugged, and took them from Eijirou without a word. As he did, their fingers brushed, and both of them gasped at the same time. Kirishima felt the same tingle in his fingertips like he’d felt - had it really only been two days ago? - when  he’d first touched Bakugou in heat. Because that's what this was, he realized blearily, staring at his hand before looking up to meet Katsuki’s gaze with his own. Katsuki’s heat wasn't being suppressed enough, and it was hitting him hard. Something at the back of his mind was shouting warnings, but Kirishima ignored them all, reaching out to touch Katsuki on the cheek. The other boy melted into his touch, whining low in his throat as his eyes fluttered shut. Suddenly, he stiffened, eyes flying open with dangerous intensity. He pulled away from Eijirou so fast that he nearly toppled over. “Fuck you!” he rasped then, slamming the door in Kirishima’s face.

Kirishima blinked, dazed. His guts felt all tingly and mixed up inside, his palm felt impossibly warm where he’d touched Bakugou. He realized he was breathing hard, even though he hadn't been doing anything. His heartbeat pounded in his ears and he stood there, staring at the door, his mind whiting out like static. He felt rooted to the spot, his chest heaving as he gasped for breath. He felt small, like the door was looming up, up, up, high above him. A hollow emptiness seemed to open up inside him, wanting, needing like he was hungrier than he’d ever been in his life.  But it wasn't quite like hunger. It was deeper than hunger, something raw, something primal, something demanding and insistent and frantic.

“Kirishima?” A voice called down the hall.

Eijirou jumped like he’d been woken from a daze. In a sense, he supposed that's exactly what had just happened. He looked back at Bakugou’s door, heart beating wildly in his chest. His hand was resting on the doirknob. Why? What had he been doing ? What had just happened to him? As his mind slowly returned to itself, panic began to set in. What had he almost done?

Kirishima spun away from the door, turning to run down the hallway, crashing into Kaminari, who had made it all the way down to where he’d been standing outside Bakugou’s door in the time it took for him to process the situation. “Sorry!” Kirishima yelped, jumping back. His body still felt strange all over, tingling, but not like when his arm or leg fell asleep from staying in the same position for too long. It was almost a flutter, his heartbeat singing through his veins.

Kaminari was eyeing him with concern. “Why were you…” he made a face. “I mean,” he tried again, slowly snaking an arm around Kirishima’s shoulders, gently maneuvering himself between the redhead and Bakugou’s door. He began slowly moving down the hall, taking Kirishima with him. “What's up with you standing in the middle of the hallway?” he asked with forced nonchalance.

Eijirou wished he had an answer for that, He didn't even seem to be capable of words at the moment. Everything around him was just sensation and scent. Kaminari smelled sharp, like the smell of lightning in the air before a big storm. His arm was solid and sure, but not constricting, and Kirishima allowed himself to be lead back to the stairs and down a flight. As they walked, the smells around them changed. He could smell so much, everything and everyone was surrounding him. Some scents he could pick out in particular - Denki, of course, but also Ashido. She smelled like... citrus and a hint of deep musk. She was coming down the hall towards them. Were girls even allowed in the boys side? Why was she here? He blinked hard, still trying to figure out how to ask that question when she slapped him. Lightly, more of a tap than something intended to do harm. But it was unexpected, and it made a loud smack when it connected with his cheek. “Kirishima!” she snarled.

Beside him, Kaminari cringed, though he kept holding on to Eijirou. He looked between the two of them, apparently unsettled by the furious look on their classmate’s normally cheerful face. Kirishima didn't like how Ashido was scaring Kaminari. His bro didn't deserve that kind of aggressive behavior. He opened his mouth to tell her to back off, but all he managed was a low growl in the back of his throat. The hairs on the back of his neck prickled. He squeezed his eyes shut, confused. What was wrong with him? Why couldn’t he talk?  He felt Ashido lay a hand on his shoulder.

“Kirishima,” she said softly, “I think…” she coughed delicately. “You're going into rut.” She shrugged weakly. “Sometimes a surprise, like a quick smack to the face is enough to snap an alpha out of it, but…” she shrugged weakly as if to say ‘oh well.’

Kaminari stiffened beside him a little, but made no move to let go of Kirishima’s shoulders. “Is he really that bad off?” he asked Ashido, voice quavering a little. “I mean, he was acting a little weird, but…”

Ashido stared at Kirishima seriously. “Can you answer me?” she asked, voice calm.

Swallowing hard, Kirishima tried to formulate a sentence, but it was like every word he arranged in his mind vanished as soon as he'd found it. He opened his mouth, found that all his words had fled, and closed his mouth again, shaking his head slowly.

Ashido nodded sharply. “Do you have blockers?” she asked, getting serious.

Numbly, Kirishima shook his head.

Ashido turned to Kaminari. “You feel comfortable taking him to his room?” she asked. “I’ll go get my blockers.”

Kaminari nodded. “I’m a beta,” he said, “it should be fine.”

Ashido pointed a finger at Kirishima. “If he gets snippy or aggressive, just back off.” She frowned thoughtfully, “or tase him.” she nodded meaningfully at Kaminari. “Not too harshly, mind you, but enough.”

Denki looked uncomfortable, but he nodded to show that he understood, tightening his grip around Eijirou’s shoulders and tugging him away from Mina and down the hall. “Thanks, Ashido,” Denki called back over his shoulder.

Ashido was already hurrying back down the hall. “Keep him away from any other omegas!” she yelled over her shoulder, “He might trigger their heat!”

“Got it!” Kaminari called after her, then clicked his tongue, turning to Kirishima. “You're in trouble,” he teased, though it sounded a little too forced to be genuine.

Eijirou couldn't disagree with him.