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Can't Fight the Moonlight

Chapter Text

It had been two weeks since Izuku Bakugou had told his family about his quirk. Surprisingly to Izuku, everyone had taken the information rather well, even his explosive older brother. Nobody looked twice anymore when Izuku used his powers in the house, even when he sprouted fins, scales, and a tail at the dinner table. It was just the new norm in the Bakugou household. 

Izuku sat in front of the freezer, an intense look of concentration etched upon his face. For the past few hours, he’d seated himself on a chair with the only company being his notebook, which he absentmindedly wrote in with his free hand. The other hand was curled into a tight fist. Currently, the refrigerator was off-limits to anyone in the house, at least until he was finished with what he was doing. Extremely stiff and sore, his hand burned from being in the same position for so long. If his hand moved in the slightest, it would be disastrous, because then Izuku would have to redo this entire thing. 

However, it had been long enough, so it wouldn’t hurt to check on his project. 

Very carefully, Izuku used his free hand to open the freezer. When he saw that his gift was in one solid piece, he closed the door once more and let his hand relax. Just to get the blood running through it again, he opened and closed it several times for good measure. 

Without warning, someone’s footsteps sounded from behind him, and Izuku had to jump to block the perpetrator— his brother, Katsuki— from jostling the fridge with his roughness.  “Don’t touch the fridge!” He spread his arms to encompass the refrigerator’s bulk. “My gift’s in there!” Katsuki looked incredulous at the statement, and Izuku’s eyes became theatrically wide. “Don’t tell me you forgot, Kacchan!”

“Of course I didn’t, you shit!!” Spoke Katsuki in his normal voice, which was the equivalent of yelling. “LOOK! I got them a freaking card, see?!” Nearly crumpling it in his grip, Katsuki held out a light-purple envelope for emphasis. 

“Okay, put that away— Mom will be home in an hour or so.” If Katsuki didn’t lower his voice, their dad would certainly stop his own work to see what was going on, and then both of their surprises would be ruined. 

“Don’t tell me what to do, you shrimp-ass!”  

Izuku had an insult that was just as creative the tip of his tongue. However, it was at that moment that Mitsuki opened the door. 

The switch was immediate. 

“Hey Mom!” Izuku greeted with an enthused smile, no longer on the brink of verbal war with Katsuki. When he crossed the distance from the kitchen to the foyer, his grin was infectious, and Mitsuki couldn’t help the smile that spread on her own face at the sight of her sons, even though Katsuki still wore that perpetual pout. 

“Happy anniversary, honey!” Masaru nearly sang, coming from behind to sweep Mitsuki up in a hug and spin her around. The gesture nearly melted Izuku’s heart, while Katsuki turned away in distaste. 

When they parted, Masaru asked her: “How’d you get off work so early?”

“Heh, I’d say you sound a little upset about that, Masaru.” She joked. “If you must know, some of my coworkers overheard about our anniversary coming up, and they convinced my boss to let me out early today.”

“No kidding.” Masaru’s face was impressed. “That guy’s a stonewall.” 

“What about you boys?” Mitsuki shifted her attention to her sons that had been standing in the foyer the whole time. “How’re you doing?”

“Great!” Was the response from her youngest, and Izuku’s eyes widened as if suddenly remembering something. “Wait, actually I have something for you and Dad. Stay here!” Then he skittered back into the kitchen. 

The moment Izuku left, Katsuki shoved something rectangular in his parents’ faces. After registering that it was an envelope, as the object was so close in her face, Mitsuki took it, but not before Katsuki barked out, “Happy anniversary.” 

With the craftsmanship of the card, it looked to have come from a store, although both Mitsuki and Masaru could clearly see bits of residual glue here-and-there and smudges of ink around the fancy-looking calligraphy— evidence that it had been handmade. Katsuki braced himself for the collective glomp from his parents and allowed them to say their thank you’s. At least they hadn’t gushed over the fact that it was him who made the card. 

Izuku came back no less than a minute later, his own gift in tow. He was wearing his pleather gloves to carry it, so it was easy for Mitsuki and Masaru to guess that whatever he was holding was made of something watery.  

Izuku grinned from ear-to-ear, as he uncovered his present: an ice sculpture. “Happy anniversary, Mom and Dad!”

With the little fractals of light beaming through all sides of it, it gleamed like crystal, rather than the ice it was. Consisting of two frozen lilies, they framed a heart in the center, which had his parents’ names and wedding date embossed in blocky lettering. It was frillier than anything Izuku would’ve thought to make, but he always went overboard when it came to gifts. 

Additionally, if the looks on his parents’ faces were anything to go by, his efforts were more than worth it. 

“Izuku.” Mitsuki took the frozen piece with careful fingertips. “I thought you couldn’t freeze water.”

“I-I kind of did. And didn’t, because it wasn’t me freezing the water. I just kind of shaped it, and then I waited for it to solidify.” Izuku clarified, the tips of his ears reddening as he spoke. It wasn’t that he couldn’t freeze water; every time he tried, the strain left him with a tremendous headache. “It actually took a while before I could get the shape just right with my hands, and even the lettering was difficult to do…” He trailed off. “You can kind of see where I got a little sloppy on the heart, but at least I could fit everything there, right?”

“Who cares about the letters? This is amazing!” Mitsuki grabbed Izuku in a one-armed hug, mindful of the ice sculpture in the palm of her hand. 

“I’m gonna have to agree with your mom right there, kiddo. Wish this was actual gemstone so we could keep it forever, but we’ll have to settle for the fridge for now.” Masaru laid a hand on Izuku’s back, also wary of the delicate gift that could shatter if he wasn’t careful.  

“Quick,” Mitsuki urged, “Take it before I drop it or something.” Holding the ice out in one hand, she allowed it to float from her grasp and into Izuku’s, who went back to the kitchen to return it to the fridge. 

“Speaking of all these gifts... “ Masaru pulled two golden tickets from out of nowhere. “I have something for you too, honey.”

“What is it?!” Mitsuki asked, curiosity shining in her eyes.

“A table for two at the Heroes’ Lounge!” Masaru said grandly, handing one of the tickets to her. “Turns out my coworkers wanted to make our anniversary special too.”

“The Heroes’ Lounge?!” Izuku gasped, his voice carrying over from the kitchen. “Isn't it impossible to get a reservation for that place?!”

And he was right. As a hotspot for Tokyo’s rich and famous, the waitlist was infinite. A month guaranteed a small table in the back; two weeks, and an individual would be lucky to stand in the lobby all night long. Additionally, its namesake held true for the amount of heroes that frequented the restaurant, who typically got priority over the richest of customers; and even the small-name heroes had a difficult time getting a table there. 

“Shit.” Mitsuki pouted; she could only imagine how many hoops Masaru and his coworkers had to jump through to get them those tickets. “Now you’re making me feel bad that I didn’t get you anything.” 

“That’s really okay, honey. I know how hard you work.” Although both of the parents had well-paying jobs, it was Mitsuki who spent the most hours at her job and away from home. “In all honesty, the greatest gift of all would be if you enjoyed yourself tonight.”

At that statement, Mitsuki threw herself at Masaru in a tight hug, and he returned the embrace. 

“I think I remember why I married you, Masaru.” Mitsuki said through the hug, completely and utterly grateful for the man she called her husband. “I’ll be ready in fifteen minutes.”

Twenty minutes later, Masaru and Mitsuki had donned themselves in their best evening formal wear. Paired with a tie, Masaru wore a white shirt and dress pants. The click-clacking of heeled-shoes from the other end of the room alerted Masaru to Mitsuki's arrival, and he removed his glasses once or twice to make sure he was seeing correctly. 

“Honey,” Masaru breathed when his wife stepped into the kitchen. “You look absolutely stunning.”

Mitsuki was dressed in a satin, floral midi-dress, which had been last year’s anniversary gift from her husband; with the piece being so fancy, she had never gotten the opportunity to wear it until now, but it surprised both of them at just how flattering it was. 

“Don’t sell yourself short either.” Chided Mitsuki, playfully elbowing Masaru as she strode past him. “You’re the resident fashion-expert.” Then she turned to her sons, who were just finishing their dinners at the dining table. “We’ll be back by twelve, so have your asses in bed before then.” Everyone knew who that statement was directed at, so nobody dared to argue. 

“Behave boys.” Were Masaru’s final words before he and Mitsuki were out the door. 

“See you later!” Izuku waved, and Katsuki turned back to the living room after the door was shut. Absentmindedly, Katsuki paged through his homework for a while, mentally scoffing at all of the problems he’d completed. Too easy. 

Come to think of it, the house was strangely silent, which could only mean one of two things: first, Izuku could’ve already snuck outside through one of the windows and was already halfway across the shitty bay. If not, he was probably concocting some sort of  experiment with his powers. There wasn’t any noise coming from the kitchen or bathroom, so Katsuki crossed that off his mental list. That only left their bedroom unchecked, which was where Izuku probably was, and, if he was in their bedroom, then there wasn’t much he could do. Still, not knowing what kind of shit Izuku was getting into at the moment was wearing on his nerves, because the brat wouldn’t be doing anything as long as Katsuki could help it. 

Much to Katsuki’s utter surprise, Izuku actually was in their bedroom, seated in a chair with his notebook in one hand and a pen in the other. His younger brother looked puzzled when Katsuki barged through the door like an enraged bull, the veins on his forehead ready to burst. 

“You’re not leaving this shitty house tonight— at all! Got that?!” Katsuki stated with finality.

“That’s...already what I was planning to do, Kacchan.” Izuku said slowly and carefully. "I'll be asleep in a bit."

Katsuki gave him a look, like he didn’t actually believe him, because Izuku never, ever went to bed early. But when Izuku turned back down to his notebook, as calm as calm could be, it seemed like he was telling the truth. When his parents weren’t home, it was Katsuki who made the rules, and he expected those rules to be followed. 

“Still, if I see you by the front door tonight, don’t expect me to be freaking nice about it.” After having spoken that last sentence, breathing in the near-toxic fumes of their bedroom, Katsuki’s face curled up in disgust. Whether or not it was the week-old yogurt in the corner of the room, the surplus of gym socks that littered the floor, or Izuku’s shrimpy self (does that shitface even bathe?), something smelled absolutely rotten. 

A cold feeling settled in Izuku’s gut like liquid-ice when he noticed Katsuki reaching for the window. “W-What are you doing?!”

“Opening these piece-of-shit blinds.” In the blink of an eye, Izuku’s face had gone from calm to frantic. 

“WAIT NO!!” Arm outstretched, notebook and pencil discarded on the floor, Izuku made a jump-tackle at the last second, right as Katsuki released his hold on the roller-blinds. A meter away from his target, Izuku missed, and his back hit the floor with a thump. From behind closed eyelids, Izuku could feel rather than see the cool light that streamed through the window, and he dreaded what was to happen next. Hoping against all hope that the blinds hadn’t been opened, Izuku cautiously cracked open one green eye from his place on the floor, and then the other. 

What met him was the face of the full moon. 

Katsuki, being Katsuki, had attributed Izuku’s jump to the floor as his little brother just being a dramatic little baby who couldn’t handle some cold air. Except, after he’d opened the blinds, Katsuki found Izuku simply laying on the floor. If he didn’t know any better, he’d say that Izuku looked catatonic. 

“Oi! Izuku! Get off the floor, dumbshit!!” Katsuki kicked him once, then twice for good measure, but Izuku just stayed in place, staring up at nothingness. At a closer look, it appeared that Izuku’s pupils had expanded to their limits. Paired with the small grin, the expression he wore looked absolutely disturbing. 

“Hehehe…hehehehehehe…” Izuku sniggered, the smile on his face gradually widening. “HEHEHEHEHEHEHEHEHEHEHE…”

“What the actual—“ Katsuki’s next words were cut off by the bottle of water that shot at his face from the other side of the room. It failed to hit him by a few centimeters and slammed against the wall with a thud. 

“YOU LITTLE ASSHOLE!!!” Raucous laughter sounded from the floor.

“You little asshole—“ Izuku mimicked, swaying as he rose into a standing position. “Hi I’m Kacchan, and I have anger issues ALL the time wike a wittle baby girl.” Several raspberries punctuated the statement. 

An angry Kacchan was a very dangerous Kacchan— vicious as a rabid bear and the scourge of Musutafu’s bully population. His continual anger was one thing, but there were few things that sent Katsuki Bakugou into a truly vicious rage. 

Such examples are: insinuating that Katsuki has anger issues, insulting Katsuki’s manliness, and calling Katsuki a baby. Izuku had done all three of these things, and, if the seething look on his brother’s face or the crackling palms were any indication, Izuku was toast. 


Izuku, even under the influence of the full moon, still retained his sense of self-preservation. He knew a threat when he saw one, which is why he barely dodged the incoming right hook by a hair’s breadth. 

At the shock of being near-punched, Izuku screamed a bloodcurdling screech, and Katsuki had to cover his ears at the sheer volume. Nobody— sans a certain voice hero— should have been capable of producing such a noise. Still screaming like a a banshee, Izuku ran out of the room, arms flailing alongside him. 

Meanwhile, at the Heroes’ Lounge, Mitsuki and Masaru had finally gotten seated at their tables and had just ordered their entrées when Mitsuki’s phone started ringing. 

She picked it up with the feeling that it was either Izuku calling to ask what shirt she needed ironed for tomorrow; or it was Katsuki, who was going to exaggerate something Izuku had done with his quirk again. Much to her chagrin, it was the latter of the two. 

“MOM!!” The furious voice of Katsuki yelled into her ear. “IZUKU’S ACTING LIKE A PIECE OF SHIT!!! I’M GOING TO KILL THE FISHFACE AND FREAKING MAKE HIM—”

“Did he find the Red Bull?” Red Bull was a forbidden substance in the house, which only Masaru drank when he pulled all-nighters. Each can was hidden in a different location, far, far out of Izuku’s reach. The one incident that Izuku found and chugged the entire stash was an instant that everybody had purged from their minds— at least until now. 


“Maybe try his notebook.” Mitsuki suggested. 

“WHAT?!” Katsuki barked. 

“I think there’s one about himself that Izuku keeps somewhere. It’s probably your best bet right now, shit-for-brains.”

“Where the hell is it?!” Footsteps and sloshing sounded from the hallway, which were getting closer and closer as he spoke. Red eyes flicked to the doorway, seeing nothing but empty space. “Before he tries to drown my ass!!”

“I don’t know! Look in your room...” Then she added. “...If you can find it through the mess.”

“That’s where I am, you—“ 

“KACCHAN!” Katsuki’s sentence remained incomplete. He didn’t know when Izuku had showed up in the doorway, but he looked absolutely affronted— more affronted than he’d ever seen Izuku in his life; consequentially, that affronted look morphed into an expression of pure furor, Izuku's hands curing into tight fists. “Are you insulting Mom?!” 

For once, it was Katsuki that actually looked like he’d been caught with not one, but two hands in the cookie jar. Evidently, he had forgotten who he’d been trapped with in the first place— Izuku, his fish of a little brother, who knew no limits when it came to defending his family, even in his current state.

A sizable globe of water snaked into the threshold. 

Oh shit.

“EAT MY RIPTIDE YOU HEATHEN!” Kastuki ducked to avoid the oncoming blast, scanning the floor as he dodged. Like the explosions that the blonde had at his fingertips, those water-blasts really did hurt, which was why even Izuku pulled his punches during their spars at the beach.

“What just happened?!” Now his dad sounded a little worried. “Nothing too bad honey. Apparently, Izuku found the Red Bull again.“

“Ah—“ Said Masaru, like that explained everything. “Poor Katsuki.”

YES! POOR ME!!” Katsuki rolled to the side to avoid another projectile. 

There were quite a few of Izuku’s notebooks among the mess that covered the floor. Hero Analysis for the future #11, Hero Analysis for the future #12... Partially concealed by Izuku’s duvet was another notebook. Its cover was nondescript, but, if Katsuki had to guess, that was probably the fabled Izuku-notebook. 

Another blast of water shot towards Katsuki. And another. And another. All of them left dents on the wooden floor. 

Through the series of attacks, he was able to grab the notebook, while his other hand lit up threateningly. Thankfully, the hallway was clear as Katsuki dashed towards the adjacent bathroom, slammed the door shut, and locked it before slumping to the floor in relief. 

Immediately, he flipped open the book. 

Kacchan, if you’re reading this, get out now! Read the first page. 

STAY OUT OF MY BOOK!! I MEAN IT!!! There was a very angry caricature of Izuku on the second page. 

Please? The third set of pages had a very sad looking doodle of a kitten. It was a reasonably good drawing, cute enough to convince their dad and possibly their mom to close the book if they’d been the ones to hold it, but nothing would deter Katsuki from his life-or-death quest for knowledge. 

There were diagrams, drawings, observations, and Katsuki would admit that, if he’d taken the time to read through them all, there were some pretty decent theories on the inner-workings of Izuku’s quirk. However, he could only afford to skim over each page in hopes that he’d find out whether or not sudden-psychopathy was included in Izuku’s powerset. 

When it didn’t come to cleaning their room, Izuku was very well-organized, and there was a whole section dedicated to the drawbacks of his quirk and the possibilities of how to fix them. Within seconds of flipping through the section, Katsuki found what he needed. 

Full moon: Looking at full moon causes a loss in consciousness; not sure what happens in the meantime, except that I become very crazy, angry, excitable, or all of the above. During this time, abilities also fluctuate.  

In the entire time he’d been locked in the bathroom, Katsuki had forgotten that the call was still active. Putting the phone back to his ear, he was grateful that his mother had remained on the line for so long with her similar level of patience, and he coughed to show that he was listening. 

“Katsuki— how’s Izuku’s…caffeine high?” Mitsuki put an emphasis on the last two words. 

“IT’S THE FREAKING FULL MOON!” He yelled very loudly into the mouthpiece. From the restaurant, Mitsuki had to hold the phone away from herself at the ear-splitting volume of her oldest son. 

“What? Full moon?” The woman’s voice was baffled. “You’re talking bullshit right now.”

“Do I sound like I’m joking to you!?” Katsuki bellowed, unamused by his mother’s snark in such a serious situation. “Apparently it’s happened before, and he goes psycho like a shitty fish-werewolf or something!”

“Can it be fixed?” Mitsuki inquired smoothly. 

Lasts until moon disappears. 

“NO! IT CAN’T!!”

There was a beat of silence before Mitsuki started again. "You opened the window, right?” Katsuki gritted out a yes. “Then, if I’m not mistaken, it was your fault that Izuku saw the moon in the first place. So now, you’re going to sit tight, shitface, take care of your brother, and if either of you are seriously injured when we get back—“ Mitsuki paused. “—your gym membership is toast.” The conversation ended then and there. 


Outside the door, Katsuki could hear Izuku doing who-knows-what from downstairs as he hummed the Mappy Arcade theme song very obnoxiously. Having left the Izuku-book back upstairs, he crept down the staircase on the balls of his feet, scanning each room for the Jekyll-Hyde terror that his brother had become. 

Katsuki had just passed his dad’s workroom and was almost in the living room, when the last voice that he wanted to hear spoke up from behind him. 

“Hey. Hey, Kacchan.” Izuku called, pupils still unnaturally wide. Paired with the ear-splitting grin he wore, he looked absolutely insane. “Hey, hey Kacchan.”

“WHAT?!” Screamed Katsuki. 

“Water!” Katsuki was met with several liters of water, a great deal of it landing in his open mouth. He gagged and spluttered, while more laughter rang from Izuku’s end of the room. 

“You—your face looks so funny, Kacchan!” As water dripped off his hair and down his face, Katsuki made it a resolve for when Izuku finally got out of his shitty episode: his ass was grass, and Katsuki would be the very explosive lawnmower. 

Forget the gym membership.

Katsuki charged. 

No time like the present, right? 

A chase ensued between the two brothers, where Izuku lead Katsuki through the entirety of the house. Izuku bounced from couch-to-couch, laughing the entire time as Katsuki tried and failed to grab him. Of course this only sent Katsuki further and further into a seething rage, every lunge that he made for Izuku becoming increasingly erratic. 

“Stay still so I can kick your ass—“ A grab, a miss, and a taunt. “—YOU LITTLE F—“

Stopping in his tracks, Izuku comically gasped, cutting Katsuki off before he could voice his profanity. “THAT’S A BAD WORD!!”

Green eyes became glossy. “W-why would you say that, Kacchan?”

“CAUSE I FREAKING CAN! THAT’S WHY!!!” Was the instant retort. 

Izuku’s face scrunched up, shifting from peach to a very angry red. From the kitchen sink, which had been left running by Izuku himself, he summoned yet another globe of water over his head. His arms were poised to launch it at Katsuki, ready to make him pay for all the vulgarities he’d said—

When Katsuki landed a Charlie-horse on his shoulder.

Focus lost, Izuku’s control of the water abruptly ended, and the orb splattered onto him and the surrounding furniture. Still, that didn’t stop him from dashing off into the kitchen to resupply himself, uncaring of what would happen next. A flash of light later, and Izuku shifted into his aquatic form, falling to the floor with a splat. 

“HAH!” Katsuki grinned triumphantly, marching back into the kitchen to switch off the sink. “Try to shoot me with water now!”

Undeterred, Izuku shuffled forwards on his stomach in the direction of the sink that had just been turned off; but when the repetitive motion irritated skin and scale too much, he settled for the closer refrigerator instead, because there were plenty of liquids in the fridge for him to use. 

“Oh no you don’t!” A yank on his tail, and the targeted fridge was out of reach. Izuku gripped the floor with webbed hands, but they slipped off the tile much to his dismay. Katsuki then pulled him off the ground, carried him from the kitchen, and deposited him on the couch quite harshly. 

Katsuki turned on his heel, wanting a reprieve from Izuku’s lunacy. However, another, long scream made him stalk back to the living room— at least to get Izuku to shut the frig up. 

“KACCHAN!!” Izuku wailed, tail swishing up and down against the arm of the couch. “Foooooood…”  

What the—“ First attempted assault and now mood swings; if the night wasn’t already weird enough, then Izuku’s sudden change in demeanor really threw off Katsuki.

“I’m sooooooo hungry.” He bawled. “And I feel kinda weird— like my mouth is really dry, and—and my ears feel weird too.” Izuku grabbed onto one of the ears that had changed with the rest of him. 

He didn’t know what Izuku would do if he did or didn’t get food, and Katsuki didn’t care at this point; but there was also the possibility that his brother would start that horrible screeching again. 

Katsuki grit his teeth, settled on what he’d do next, because maybe, just maybe, some food would placate Izuku’s scaly ass. 

A minute later, Izuku was happily munching on a bag of tuna flakes. With gusto, he tore through the bag in a flash and demanded another one…and a drink. 

Turns out, if you give a fishboy a bag of tuna, he’ll ask for a juice box to go with it. 

Crossing his arms on the opposite couch, Katsuki had several more bags of tuna situated next to him (the Bakugous bought dried tuna flakes in bulk), along with a dozen juice boxes. When Izuku finished one and requested another, the blonde would chuck it at him none-too-kindly. The shit he still did for his fishy-ass brother. 

“Kaaaachan…” Izuku whined. 


“I don’t like cranberry juice. I want the tropical one instead!” Green eyes were pleading. 

“Too bad! Cause that’s all we have, and I’m not going back in the kitchen to look for a different flavor!” Katsuki settled himself further into his respective couch to get his point across.

“But I really, really waaaant it! Give it now!” 

That was the final straw for Katsuki, who— with a cranberry juice in hand— marched right up to Izuku and shoved the juice box in his face.

“No!” Izuku flailed on the couch, using his arms to keep both Katsuki and the juice box at bay. 


“NO!” With the insidious juice box inching ever-closer, Izuku went from squirming to full-on thrashing, using all the strength in his body to scoot away from Katsuki. 

For one final time, Izuku reached to block the juice box. 

Elbow hit face, and the two brothers recoiled. 

“STUPID SHITTY ELBOW!!!” Katsuki jumped backward from the hit, juice box entirely forgotten. A hand flew up to his cheek, meeting tender skin. The hit had struck his cheekbone, and it hurt— a lot. “I’m going to the bathroom to see what you did to me, and if so much as one scale of yours is off that shitty couch…” He left the threat hanging in the air. 

Izuku didn’t say a word, but he looked ready to cry as he curled into himself as much as possible. 

Good. Katsuki huffed. At least Izuku remembered who was in charge now. 

By the time Katsuki returned from the bathroom, where his face was thankfully not bleeding, Izuku had fallen asleep, a finished cranberry juice box clutched in one hand. 

The entire time he’d been transformed, Izuku had remained relatively dry, so why the frig wasn’t he changing back? Since this had already happened to Izuku before, Katsuki reasoned that this might also be part of the whole full moon thing. It was nothing to pester his parents over like a crybaby again; they could deal with it when they got home. 

For now, flicking off most of the lamps, it was time that Katsuki got some well-deserved rest. 

But, if Izuku woke up again—

Katsuki fumed, aware of the fact that he’d be spending the night on the couch. It wasn’t that it was uncomfortable; he simply preferred his own room. Still, he couldn’t leave a crazed Izuku to his own devices. He’d probably flood the whole house if he could. 

After shoving the leftover stockpile of food he’d gathered onto the floor with an arm, the blonde pulled a spare blanket over himself, and he was just about ready to go to sleep, when Izuku started tossing and turning— more precisely, he was shivering. 

Frig. Wasn’t he cold-resistant or something? Katsuki thought, suddenly irate again. 

Yet, he wouldn’t be able to sleep with knowledge that there was motion from somewhere in his line of vision. Even if his eyes were closed, it would just be plain freaking annoying. 

With irritated reluctance, Katsuki slinked out of his warm blanket cocoon and headed back upstairs to retrieve another duvet for his brother. 

He threw the blanket over Izuku and tucked it into both sides of the cushions so he wouldn’t have to pick it up off the floor, because he wasn’t planning to get up once he went to sleep himself. Within minutes of being covered, Izuku snuggled contentedly into the sofa. 

Similarly, Katsuki plopped on his own couch, pulled the blanket over his shoulders, and closed his eyes, letting sleep overtake him. 

Awareness came back to Izuku in bits and pieces. The pounding in his head registered first, and his whole body felt as if it had been sent through a meat grinder. As per usual, his legs felt like gelatin— the half-fridged kind that didn't keep its shape—so, the last thing he’d try to do would be walking for a while or even standing for that matter. There was also a sharp pain in his right shoulder, like someone had punched him. Hard. 

“Uugggggghhhh…” He knew what had happened: Katsuki opened the window in his room, and he’d blacked out then and there. He wanted to go back to sleep so desperately, but the sunlight that pierced through his eyelids prevented him from doing so. 

“Morning, sleepyhead!” Masaru greeted cheerfully. 

“Well, well, well…” The voice of his mom started. “Look who finally decided to wake his ass up. By chance was there anything you forgot to tell us, shitface?”  

What did his mom even mean? Everyone already knew everything about his quirk, like the water control, the fins, and— oh, right. 

“The moon!” Izuku shot up into a sitting position, an intense wave of vertigo pulsating through his skull. Truth be told, in the time leading up to the full moon, he had no clue on how to even broach the subject. Hey guys, I act like a freaky lunatic once a month. No, I’m not on drugs; it’s the full moon, even if WebMD says otherwise.  No matter how he worded it in his head, it was just plain weird and embarrassing. 

Regardless, he should have told his family in the first place so at least they would’ve known what would happen to him and why. “I’m so sorry guys! I was supposed to tell you when I told you all about my quirk, but I completely forgot.” His face grew frantic. “I-I didn’t do anything horrible, did I?” 

“I think you scared Katsuki half-to-death—” Mitsuki gestured to the side. 

“SHUT UP!! I WAS NOT SCARED ONE BIT!!!” Katsuki’s volume sent another wave of pain throughout Izuku’s head. 

“That’s why you were on the phone with your momma for half the night.” Teased Mitsuki. Masaru stifled a laugh at the comment.  


“Riiiiiight…” Mitsuki drawled smugly. Then she turned her focus to Izuku, ignoring the other fuming teen behind her. “So this happens every full-moon, Izuku?” 

“Yeah.” Izuku breathed. “I-I actually was supposed to try going all night shut in my room, because I have a hard time sleeping on full-moons now. Kacchan opened the window though, and you know what happened.”

“And you don’t remember anything?” She asked, genuine interest in her tone. 

“Not really.” He admitted. For the past couple of times he’d blacked out, Izuku could barely recall what he’d done. Sometimes, he could remember sensations, like the feeling of using his powers or having his legs merged into a tail. Emotions were another thing. Exhilaration, frustration, outrage— all of them left a faint taste on his tongue in the morning. 

Right now, he tasted cranberries. 

“Well you’re even more demanding when you’re cuckoo-for-freaking-Cocoa-Puffs! Pain in the ass...” Katsuki interrupted. Izuku caught the splotch of purple on his older brother’s cheek, and unconsciously he brought his hand up to his own. 

A pang of guilt surged through Izuku, because he knew with certainty that he’d been the one responsible for that. 

“Kacchan.” Izuku turned to Katsuki. “W-Why didn’t you hide or something?”

“Because you would’ve set the house on fire or some shit, and don’t apologize either.” Katsuki gruffly responded. “By the way, did you know you don’t change back until freaking sunrise?!” The fact that Izuku would have a wobble in his step for a while today almost made Katsuki feel pity for him— almost. 

"Yeah," Mitsuki interjected. "You were sound-asleep when you changed back."

Huh. He hadn't known that. Izuku would have to write that down later when he got the chance. Remembering something else on the forefront of his mind, Izuku decided for another topic. “How was the Heroes’ Lounge?”

“It was wonderful! They had just about any kind of food you could think of—you would’ve loved it there, Izuku!” Said Masaru with an enthused gesture. 

“Were any heroes there?” As a hero fan, Izuku just had to know. 

“I think we saw one or two actually…” Masaru put a hand up to his chin in thought, wracking his mind for the hero knowledge he gained from Izuku’s muttering around the house. “There was Gunhead, and I think we saw that guy with the jeans on his face—Best Jeanist!” 

“You know,” Spoke Izuku, sinking back into the cushions. He was just about ready to fall asleep again. “When I’m a pro hero, I promise you that I'm gonna take us all back there someday.”

"Now you're making me feel guilty about wanting to video-tape you on the next full moon, Izuku." And Mitsuki had to admit that Izuku was a little too selfless sometimes. 

"She's right." Masaru slung an arm around his wife. "We could get a pretty penny on Quirkiest Home Videos if you wanted." Despite the fact that Masaru was completely joking, an angered 'It was not freaking funny' came from Katsuki's end of the room. 

"Don't worry." Mitsuki waved off any of Izuku's further worries, even though he knew she wouldn't (unless he did something particularly funny). "We won't; we'll keep them for ourselves. Just go to sleep now, Izuku." And Izuku took that as his cue to close his eyes. 

Full moons took a lot out of Izuku. From the overuse of his powers, to the extended time in his aquatic form, and the emotional overload— it all left him exhausted.

Thankfully, even with the knowledge that he had a quirk that rendered him so volatile, unhinged, and then so tired and feeble-bodied afterwards Izuku could rest easy.

Because, with his family behind him every step of the way, he would never truly be alone.