“Remember, Eijirou,” Kirishima Isami said to her son when his soulmate mark first appeared, “you never know what your soulmate will be like, so don’t create something in your head that could never be real.” Even though his mom had gotten lucky enough to have found a perfect soulmate in his mama, she liked to keep his world realistic.
And, over the years, Kirishima had held onto that idea.
When he would look at the little mark on the underside of his left arm at night, he would know that somewhere out there someone else had the exact same shape in the exact same place on their body. But he didn’t try to imagine them. He didn’t imagine a face or a name or a personality. When his friends would talk about it he wouldn’t contribute.
Because in his heart he had a feeling that his soulmate would outclass every expectation he could possibly have.
When he got to high school, into the hero course of his dreams he had the feeling he might meet his soulmate there. Or at least he’d hoped. It seemed like the perfect place, right? The romantic ideal! Meeting the person you’re meant to spend your life with in high school, it was like, the dream wasn’t it?
A few people compared marks at the beginning of the year, he and Kaminari and Sero had been quick to share, Mina had been too. He had a feeling that some of the others had shown them to their close friends as well. Hell, there was even a match or two in the first few weeks, which was exciting and awkward just like the novels made it out to be.
He saw Bakugou’s entirely by mistake.
He’d had to run back into the locker room for something, catching Bakugou right as he was finishing putting on the makeup that filled in the gaps in his mask. The blond had taken a minute to stretch out his arm and there, right on the underside of his left arm was a familiar mark, almost like a star but more jagged like a saw blade. And Kirishima would recognize that mark anywhere . It was the same mark that he’d looked at in the mirror over and over again, the same raised mark he traced with his own fingertips repeatedly over the years.
Holy shit Bakugou “Blasty McSplode” Katsuki was his soulmate.
Kirishima had rushed from the locker room in a daze, the knowledge bouncing around his head in rough patterns. Holy shit. Holy shit .
He was so fucked.
The loudest, angriest boy in their class was his soulmate.
The loudest, angriest boy in the class was his soulmate and his costume didn’t have a shirt .
He just...had to be careful. That was all. Maybe try to keep a little distance. Yeah, he could do that!
Of course, as was his way, he made a plan and immediately failed.
“Bakugou! Team up with me!”
Because he’s a fucking idiot .
But, for some reason, after that it gets easier. Bakugou lightens up. Well, as much as he ever could. The Sports Festival seemed to mark some weird turning point in Bakugou. At least as far as Kirishima was concerned.
They spent time together, studied and trained because Kirishma could take the hits and Bakugou could ramp it up steadily to give them both a workout. It became normal to go to arcades and get drink specials and even go to each other’s houses. Bakugou was shockingly good with his baby sisters and Kirishima loved looking at all the photos Masaru would show him even as Bakugou and his mom shouted and screeched in the background over some aspect of dinner until the blond would drag Kirishima over to taste something or make him help clean up. When Bakugou invited him for a hiking trip it was all the more shocking for how shocking it wasn’t .
And the more he got to know Bakugou, learned about how he liked spicy food and the truly awful All-Might movies and hated natto but ate it anyway because it was healthy, the more he began to realize something.
His soulmate really did outclass every expectation he could have ever dreamed of. Under the screaming and the anger was a man who was going to be the greatest hero if it killed him, someone who was wickedly smart and fun to be around, someone who got impatient at crosswalks and liked taking short cuts that would get him hopelessly lost but inevitably lead to some strange discovery.
And Kirishima could only feel that he wasn’t good enough.
But when the news of Bakugou being kidnapped hit Kirishima didn’t care. His best friend was missing. His soulmate was missing.
Standing there, in Midoriya’s hospital room, he decided that if he wanted to be good enough he was going to make himself good enough.
“He’s my soulmate,” he told Midoriya on the train, voice quiet so the others didn’t overhear. Midoriya’s doe eyes went wide at that, hands trembling on the snack in his hands. “He doesn’t know yet.”
He muttered to himself a bit, looking at Kirishima for a long moment before patting his hand. “We’re gonna get Kacchan back,” he said, determined and scared all at once, “are you...gonna tell him, Kirishima-kun?”
“I don’t know,” the redhead responded, rubbing the back of his neck and sighing, “you know how Bakugou is. I don’t even think he wants a soulmate, he’s never talked to me about it…”
Midoriya perked up a little at that and hummed. “When we were little,” he started, voice still quiet, “he showed me his mark, under his arm right? Since mine is uh…” he played with the hair behind his ear, “well, it was more visible then. But yeah, he was excited, when we were kids to meet them...uh...you? He always talked about how strong they would be.”
Kirishima chuckled a bit bitterly at that. Bakugou expected a strong soulmate and he was saddled with Kirishima…
“Hopefully he won’t be too disappointed if he ever finds out it’s me,” Kirishima said, running a hand through his hair and Midoriya stared at him, eyes wide.
“You’re not going to?”
“I’m not planning on it,” Kirishima said, the conversation lapsing into silence despite the way Midoriya opened and closed his mouth, seeming to want to broach the topic again. But Kirishima was focused on the mission, on what they were here to do. On the fact that they could very easily die.
But they didn’t.
They soared over the battlefield hand in hand and Kirishima grinned at Bakugou who gripped him so tight, his eyes wild and his grin even more wild and touched by the moment. Part of him thought it would be perfect. To say it right then.
But he didn’t.
Instead they landed, they moved into the dorms, their lives fell into a different pattern than before, but the same. But this time the distance that Bakugou had carefully seemed to craft was gone entirely. They leaned on each other during meals and studied with their heads close together. They would spend most of their time almost attached at the hip and it felt so natural that Kirishima hadn’t noticed it happening at all.
He hadn’t noticed when Bakugou would kick his feet into his lap on the common room couch or how he would forget to let go of his wrist as he dragged Kirishima around, hadn’t noticed how the blond could be soothed by a touch to his lower back or didn’t struggle when Kirishima restrained him. Hadn’t noticed how, more often than not, they fell asleep watching something on one of their laptops. It all just clicked into place.
Hell, Bakugou would even make him dinner every so often and their sparring turned into more play fighting these days. Kirishima got to see the other boy smile , he got to hear him laugh , and Bakugou had the worst laugh, truly. It was wheezy and screechy and loud and Kirishima found himself falling in love with it even as he resisted the urge to tell Bakugou the truth.
It was easy to avoid talking about when he’d just liked Bakugou as his best friend. It was harder now that he was pretty sure he was in love.
And it was one night, a few months later, after Kirishima had come home from the hospital after his fight with Rappa where he was lying in bed and things took a hard left turn.
He was still sore from the whole affair, aching as he laid in his bed, relaxing after a long day of classes when his door was kicked open harshly and he jerked his head to the side to see Bakugou standing there, a deep scowl on his features as he shut the door behind him and locked it. The blond crossed the room quickly. “Move over,” he groused, waiting for Kirishima to comply before sitting down and grabbing him by the chin, looking into his eyes.
“What’s up, Bakugou?” Kirishima asked, confusion in his tone and written on his face. The blond looked like he’d come to some grave decision, like he was about to say something that pained him.
“I don’t give a shit who my soulmate is,” the blond said all of a sudden, like he was pushing through it, “and I don’t give a shit who yours is either.” Bakugou blushed a little as he licked his lips, trying to think of what to say next. Kirishima almost interrupted before Bakugou slammed a sweet smelling hand over his mouth, glaring, making it clear that he was going to finish, no matter what Kirishima said. “I don’t give a shit if the universe wants us to be with someone else or whatever, you’re the only one for me you fucking asshole and I know I’m better than any shitty soulmate you could fucking have.”
Kirishima felt his eyes grow wider with every word, moving to sit up, pushing against Bakugou’s palm to meet his gaze on his level. The blond was bright red, embarrassed but determined, as if he knew one hundred percent that this was the proper course of action. Kirishima found himself smiling, a laugh bubbling in his throat as he threw his arms around the blond and tugged him close, into his lap for lack of anything else to do.
“You know what, bro,” Kirishima said, voice soft for a moment, “you’re right.” And Bakugou seemed more than pleased with that, burying his hands in Kirishima’s bright red hair and tugging him into a kiss that was more teeth than lips and wow someone was gonna end up with a split lip but Kirishima did not care. It felt so good and right, like something in his brain had clicked into place and Bakugou was pushing harder into the kiss, hands sliding up the inside Kirishima’s shirt impatiently, like he’d been waiting for ages to touch and Kirishima didn’t even think as he pulled back and let Bakugou rip the damn thing off, sharp red eyes darting to his left arm at a flash of that mark.
Time seemed to stop as Kirishima, panting and flushed, watched Bakugou connect the dots in his head. Watched as dazed appreciation turned into sheer, abject rage in an instant.
“You absolute fucking douche bag ,” Bakugou snarled, pressing Kirishima back onto the bed and jerking his arm over his head. Kirishima swallowed heavily, not sure if he was aroused or in love or terrified. “You had the same fucking mark all along?! And you never fucking told me?! You had to see mine! You fucking had to! My costume is a fucking tank top. Holy shit how did I not fucking notice?”
Kirishima swallowed a little bit at that. “I-I...surprise?” he said, grinning sheepishly, licking his teeth as Bakugou’s eyes trailed over his body and over the mark and back to his face.
“Why didn’t you tell me?” Bakugou asked before covering Kirishima’s mouth with his hand as he went to answer, “you know what? Don’t fucking tell me. It’ll just piss me off more. Fucking dick. I’ll teach you to keep a fucking secret like this from your goddamned soulmate.” Bakugou then smirked, big and wide and vicious almost, like he did when he was proclaiming an absolute victory. And Kirishima found it so painfully attractive that his body was definitely reacting.
“You’ve always been mine,” Bakugou practically purred, his rough voice caressing the words like they were the best thing ever. And fuck why was that sexy? It should not have been fucking sexy. But here they were, Kirishima failing to fight the only form of hardening he didn’t have control over while Bakugou lifted his own shirt off and tossed it to the side, giving Kirishima a quick, teasing flash of that matching mark that bound them together. “And the whole fucking world is gonna know.”
Kirishima couldn’t have held in the loud, yelping noise he let out when Bakugou leaned in and straight up bit him on the neck. Not even enough time to harden up to prevent the purely massive hickey that Bakugou was leaving, working his jaw and teeth and wow that felt so fucking good that Kirishima’s skin began to tingle. It was like a dam had broken in his heart as he gripped Bakugou tight enough to bruise, a groan leaving his lips when he leaned to drag him into more kisses, turning them onto their sides and tangling their legs together in a gordian knot.
They broke the kiss breathing heavily, Bakugou’s sweaty hands buried in his hair and one of Kirishima’s having slid into the back of Bakugou’s pants a little, fingertips ghosting the top of his ass. “Means you’re mine too,” Kirishima breathed out, the words ghosting over Bakugou’s skin and the blond nipped and sucked at his lower lip aggressively for a minute.
“Dumb fuck, I know that,” Bakugou growled out, the red of his irises almost completely taken over by black, “I want that. You’re the only one I want at my side.”
And it’s stupid and gruff and romantic and Kirishima couldn’t help it when he kissed Bakugou again, devouring the words because he’s so fucking in love with the blond in his arms that he can’t think of any other way to express it than to kiss him within an inch of their lives. And it felt so fucking good to twist them, to press Bakugou into his bed, to frame his face with his elbows as their kisses slowed, to languid, exploratory things that left Kirishima’s very lungs shivering as they parted, as though he couldn’t breathe if he wasn’t kissing Bakugou.
The looked into each other’s eyes for a bit, a smirk spreading over Bakugou’s lips as he wrapped his legs tightly around Kirishima and arched his back. He looked so fucking satisfied with himself, like a cat who caught a particularly delicious bird.
Kirishima loved that look on him.
“So?” Bakugou asked, tugging at his hair, “you gonna stare all day or are you gonna do something about the hard-on you’ve been grinding into my thigh for the past ten minutes?” That had Kirishima’s face explode with a blush, swallowing heavily. Shit was it that obvious?
Bakugou pressed a finger against his lips and twisted, pinning Kirishima on his back, hands pressed to his chest and wow this was just a scene from his dirtier wet dreams wasn’t it? Kirishima swallowed heavily at the sight of him, flushed himself but looking far too confident. “You know,” Bakugou murmured, voice rough, “I thought about this so fucking much, think I spent more time jerking off to the idea than was healthy.”
That now being said, Bakugou rocked his hips in a tight circle and conscious thought fled Kirishima’s mind in a rush, pleasure replacing his myriad of questions, slightly hardened hands landing on Bakugou’s hips again, the sharp tips dragging over the curve of his ass and leaving a thin red line. Kirishima moaned as Bakugou worked his hips in a rhythm, warm hands pressed on Kirishima’s chest, looking like he was an inch away from bouncing in the redhead’s lap and Kirishima was sure he would cum in his pants if he did that. Hell, he might do that now .
“B-Bakugou,” Kirishima moaned out and the blond shivered, leaning down to kiss him harshly, gasping for air at the end of it.
“Katsuki,” he whispered, “fuck, call me Katsuki.”
Kirishima grinned at that and tilted his head to draw his teeth over Bakugou’s neck, making him groan in need. “Only if you call me Eijirou,” he whispered against the pale skin there, returning the earlier bite roughly, shivering at the sound that fell from Bakugou’s lips and into the air around them, he worried the skin there until it grew warm and he knew that the mark there was going to be there for days, weeks.
The idea sent a thrill through his body, that everyone was going to see the marks they’d left on each other. It was so fucking real.
He pulled back, drawing his tongue over the edges of the mark he left on Bakugou, feeling the little dips of the indent of his teeth and Bakugou let out a sound that made everything in Kirishima throb with want. “Eijirou,” Bakugou groaned, hands tugging at Kirishima’s hair until they could kiss again, wild and rough, grinding on each other almost frantically as their hands fluttered and gripped and bruised. Like making up for lost time.
Kirishima gripped Bakugou by the thighs, holding them tightly, the fabric slipping over the muscles beneath as they rolled again, landing on the floor with a loud thunk but neither seemed to care. The dorm beds were too small anyway. He didn’t even care that he still ached after his fight.
Bakugou held him tight, crushing almost as he grinded their hips together in tight circles, panting heavily, whines getting caught in his chest. Kirishima felt his eyes rolling in his head at the pleasure, at the fucking sight that Bakugou made beneath him, flushed and sweaty beneath him and he’d be lying if he pretended he didn’t jerk off to the idea in past months. But fuck having it in real life was filling his entire brain with fuzz and making his cock throb with need.
“Fuck, Katsuki,” Kirishima groaned, leaning down to kiss him again, bodies grinding hard and fast, the pleasure tingling at the base of Kirishima’s spine and he whined. “Fuck, I don’t wanna be gross but if we keep this up I’m gonna cum in my pants.”
Bakugou panted heavily before scowling and tugging at Kirishima’s sweatpants. “Then get them off and cum in my mouth instead, Eijirou,” he growled, demanded , and Kirishima had never gotten so naked so fast in his entire life, Bakugou shoving him onto his back and getting between his legs like he belonged there, gripping his dick and smirking. “Fuck,” Bakugou breathed out, running his tongue over the tip bravely, making Kirishima’s entire brain short circuit because holy shit this was moving fast but at the same time it felt like they had waited forever.
Bakugou let out his own little sound, taking his time, not able to take the whole thing as he circled the tip with his tongue and stroked the shaft and Kirishima knew he wasn’t going to last that long, not with the sight Bakugou made leaning over him, sucking and bobbing his head with this singular sort of determination that was intimidating and hot all at once. Kirishima panted heavily, looking down at him and running his fingers into his hair, feeling the motion under his hand and fuck it was so good. So goddamned good and he wanted to make Bakugou feel this good…
“F-fuck,” Kirishima whined loudly, “I-I’m gonna...nnnh…” And he’d be embarrassed about how quick this was going but he was so wound up and it had been such a long time and holy shit his soulmate wanted him and...and…
Kirishima moaned loudly as he came, Bakugou pressing down closer and swallowing every drop of cum, making Kirishima gasp and whine. It felt so good, so fucking good and Kirishima shuddered as he landed back on a hardened elbow, grabbing his boyfriend, fuck his boyfriend , by the hair and dragging him up to kiss him hard, tasting himself on his lips.
He tugged Bakugou close, gripping his dick in his hand and stroking, the blond writhing and gasping in his grip until he was spilling over his fingers and coating Kirishima’s abs. They shuddered in each other’s arms, whining and sharing air, sharing kisses. Because they could finally breathe .
The next day Bakugou had laced their fingers on the way to class and announced it for everyone that Kirishima was officially off limits and Bakugou was his soulmate so everyone could eat his ass .
And Kirishima couldn’t help but be stupid in love with his soulmate.
He’d have to tell his mom she was right.
He could have never imagined Bakugou Katsuki.