Work Text:
one.
It started on a random Thursday during their third year at U.A.
Katsuki wasn't sure how it happened. One moment, he was snorting at one of Kyouka's dry jokes that always got him as they entered the dorms after another tiring school day; the next, he was cleaning up the remains of a spatula that he'd accidentally exploded while making dinner.
It was a simple recipe. They always had easy-to-make meals during the week, things that wouldn't take too much time or effort on top of all the studying and training and work studies they already had to keep up with on a normal day.
So, how the fuck had that happened?
"Oh my god!" Eijirou exclaimed, jumping down from his perch on the kitchen counter, where he always sat while Katsuki cooked for them. "Are you okay? You haven't exploded any of the appliances in months; what happened?"
Yeah, Katsuki would have fucking loved to know that, too. He was just cooking, listening to Eijirou talk, and then the idiot had laughed—
"I got distracted," he said in a bit of a rush, picking at the melted plastic that had stuck to his palm just so that he wouldn't have to look at Eijirou's concerned eyes. "Must've been sweating too much without noticing. I wasn't paying attention."
"You always pay attention, dude. That's like… one of your things."
That got Katsuki to look at the moron he called his best friend, a confused frown taking up his entire face. "I don't have things."
Eijirou watched him like he'd grown a second head. "Of course, you do. You have lots of things; you cook, you run in the morning, you study as soon as the material is assigned, you braid the hair of anyone who asks—"
"I don't braid just any extra's hair, I have standards—"
"And you pay attention," Eijirou concluded. "You know everything about everyone because you're good at observing behavior, and you most definitely know all that is going on around you at any given time. So, I'll ask again. Are you okay?"
See, Katsuki hadn't always been good at this whole… caring thing. It had never come easy to him, because he wasn't good at people in general. It had taken him months of therapy after the war to sort through all the mess in his head (and in his heart), so he hadn't exactly had much time before then to learn how to read every small people thing.
Eijirou, on the other hand, was amazing at that. He could understand even a stranger after one simple conversation; he knew all of their friends' tells by heart; he was able to see which of their classmates was close to a breakdown with a single look. And of course, he was especially good at all things Bakugou Katsuki — even more than Bakugou Katsuki himself was.
Katsuki had learned most of what he knew about paying attention from Eijirou.
"I'm fine," he replied, and he meant it. "I was just lost in thought, Ei."
The redhead hummed, then dumped the remains of the poor spatula that he'd picked up into the trash. He did the same with the ones Katsuki was holding, too, and a second later, Eijirou was back in front of him. "Let me see your hand."
He scowled. "I said I'm fucking fine."
"Can I check anyway?"
When Katsuki looked up from his hands, when he made the absolute rookie mistake of looking into Kirishima Eijirou's infamous big doe eyes, he felt the need to explode something again.
And then, "Please?" Eijirou asked with the sweetest, make-you-weak-in-the-knees voice.
Katsuki was a goner.
"Tch," he huffed, hiding his blush as best he could as he thrust his right hand into Eijirou's waiting ones. "It's just a couple of scratches. They'll be gone by the weekend."
His best friend didn't pay his words much mind, inspecting his hand like a surgeon would a very complicated open-heart surgery. Katsuki would know; he'd been in the patient's position. "It looks like the melted plastic burned you a little, too. I have some burn cream in my room; I know you don't usually use it because you're used to your explosions, but i bet it still hurts like hell."
God, he looked so cute, all worried about him. Katsuki needed to get out from under Eijirou's scrutinizing, soft gaze as soon as possible, or he was going to blow up the entire fucking kitchen next, himself included. "Yeah, okay. Make it quick; dinner's almost ready."
"Great!" the redhead replied with a big, toothy smile. He let go of Katsuki's head, and he could breathe a little better already. "Be back in a minute!"
He disappeared, running out of the kitchen at inhuman speed, leaving Katsuki alone with his thoughts.
He was so fucking screwed.
two.
Once he'd noticed, he couldn't unsee it anymore.
He would've been fine if it had only happened occasionally. He could handle a few instances of it, but as it stood, Kirishima Eijirou was the cutest motherfucker to ever walk this wretched planet he'd been unfairly born on, and Katsuki, powerful explosion quirk or not, was still only human.
It didn't help that the redhead was supposed to be his best friend, and Eijirou took that job pretty fucking seriously.
That meant that he just wouldn't leave Katsuki the fuck alone.
"I keep getting this one wrong," he huffed, sprawled on the floor of Katsuki's room as they studied. "Can you show me the process?"
It was an innocent enough question. Math wasn't Eijirou's best subject, not by a long shot, and even if he'd gotten better at it, some problems would still give him trouble from time to time.
Katsuki had his own problem, though, because Eijirou was currently chewing on his pencil with the most adorably confused expression a human being could make — Katsuki didn't even know such a look could be achieved, but Eijirou seemed to defy any and all possibilities.
"Sure," he replied. His voice came out a little high-pitched, so he cleared his throat. "Let me see which one it is." He focused on the problem, scanning the redhead's process until he found the mistake. "There," he pointed out. "That's supposed to be a minus."
"Oh," Eijirou whispered, but he didn't look convinced. His cute frown deepened, and Katsuki had to take a long, long breath in. "Why? It doesn't make sense."
"Yes, it does. Look." Katsuki went back a few steps, taking out his own workbook so he could write and actually show Eijirou. He'd always been better at understanding math when it was explained and shown to him at the same time, and Katsuki had mastered this tutoring technique in their first year.
As he explained, he would glance up at Eijirou. His best friend was following with laser-like focus, still chewing that damn pencil to hell, and Katsuki had to fight himself to keep going without getting stuck staring at his cool, pointy teeth.
"You get it now?" he asked when he was done, looking back at Eijirou to gouge his reaction.
"I think so! Thank you, Katsuki. I don't know what I would do without you, I really suck at math," he said, and oh, his smile was so grateful, Katsuki couldn't stop himself.
He reached out with a hand and captured Eijirou's cheeks. He squeezed, making his lips jut out until he looked a bit like a fish, with his big red eyes looking right at Katsuki in confusion.
"Stop shitting on yourself," he told him, squeezing more when he tried to reply. "You're doing fucking fine; I'll explain again if I need to, but that doesn't make you stupid, or whatever bullshit you've been thinking about yourself in that big head."
"Oh-ay," Eijirou tried.
Katsuki squeezed again. He could feel his pointy teeth through the skin. "You're not dumb. Stop selling yourself short, Eijirou."
He nodded, and when Katsuki finally released him, his smile looked more genuine than the one before. "Okay, Katsuki. I'll try."
The blond searched his eyes for any sign of lying, but the only thing he could find was the warm red of his irises and the affection that Eijirou always showed him with no reservations, so Katsuki just huffed and turned back to his own work. "Finish the problem, now."
"Yes, sir!" Eijirou started writing immediately, his determination restored.
Katsuki looked at his cheek for a few more seconds. The skin was red where he'd dug his finger in, and something warm bloomed in his chest at the thought that Eijirou had let him hold him like that, to the point of leaving a mark on him.
three.
Katsuki watched as Eijirou laughed so hard at something Denki said that his milkshake came out of his nose.
Katsuki also realized, to his own absolute horror, that he found it cute.
He got up from the table so fast, Hanta asked him if he was okay. Katsuki just waved them off, bee-lining for the restroom as the rest of his idiots continued laughing.
It was fine. It was completely normal to think that one's best friend was cute, even when it was over something as gross as snorting a strawberry milkshake out of their nose. Right?
Katsuki splashed his face with cold water.
They'd chosen a little restaurant a little ways away from U.A., because most of the ones close-by were always full of other students on the weekends. Kyouka had found it on one of her outings with Eri — it was close to their favorite music shop, and when she'd seen the super-spicy ramen option on the menu, she'd known that even Katsuki wouldn't have been able to say no to at least trying it.
The ramen had been super spicy, and so it had quickly become one of their favorite spots in the last year or so. They tried to all go together at least once every couple of weeks, to relax and spend some time together away from school and hero duty, and Katsuki loved it.
(He also loved his idiots, even if he would never be caught dead saying it out loud.)
As it was, though, it also meant that all of them knew exactly how much time each of them usually spent in the restaurant's restroom, and so Katsuki found himself face-to-face with a concerned Eijirou when the redhead had gone to check on him.
"Hey, man," he said, those little brows forming a V in the center of his forehead, "you okay? You've been in here a while."
"Yeah," Katsuki replied with a sigh. "I'm just a little tired."
"Of course! It's almost your bedtime, huh, old man?"
Katsuki bristled. "How dare you call me an old man! We're the same age, you dumbass!"
Eijirou shrugged. "You're six months older than me. You're old."
The blond huffed, then shouldered his way out of the restroom, Eijirou happily trailing behind him like an eager puppy. "You're just a brat, then."
A thoughtful hum followed Katsuki all the way back to their table. "Is it because I'm the baby of the group? You know, I actually like that! I think you should all spoil me more, though, since I'm the youngest and thus your responsibility."
"The only thing I'm gonna spoil is the end of the manga you borrowed five weeks ago and still haven't returned to its rightful owner."
Eijirou gasped as he sat — right next to Katsuki, right where he always was. "You wouldn't!"
And there they were again, those big doe eyes of his. The red of his irises was so striking in the light of the restaurant, so warm and playful.
Katsuki wanted to bite him.
"He so would, dude," Denki interjected. "Remember that time he spoiled Stars Wars to me?"
Hanta hummed. "To be fair, those movies are like, a hundred years old. It's like complaining that someone spoiled the Odyssey, or the Bible."
Katsuki frowned so much, he could feel those premature wrinkles his mom always warned him about forming in real time. "Why the fuck was the Bible even one of the options?"
Hanta shrugged. "Everybody knows that Jesus dies and then comes back to life."
Mina turned very, very slowly towards Katsuki. "Does that make you the new Messiah?"
Everyone laughed at that.
It had taken them quite some time to get used to the idea that Katsuki had died for a bit there in the war, but a year and a half later, they could occasionally joke lightly about it.
Or at least, almost all of them could.
Eijirou never did get used to the idea that Katsuki had died while he was so far away — when he wasn't there to help, to protect him, to be his unbreakable shield.
The conversation went back to normal after that, with all the others distracted by their own little bubbles, so Katsuki sneaked a hand under the table — his right one, the one that had been messed up, the one he'd been told he shouldn't keep but did anyway, stubbornly pushing through rehab until he could use it again with barely any lingering issues on a normal day — and let it rest on Eijirou's bouncing knee, effectively taking him enough by surprise that he forgot to keep moving it.
Katsuki looked at him, studied his face. "You alright?"
Eijirou gulped. His eyes looked a little glassy. "I don't like it when you guys joke about that," he whispered, so low that Katsuki was only able to hear it thanks to how close they were sitting.
"You need to tell them, then," Katsuki said, matching his volume. "You know they won't stop if you don't."
They kept quiet for a while. Katsuki pretended to listen to what the others were saying, while Eijirou got lost in his thoughts until it was time for them to go back to the dorms.
The walk was quiet, too. They were all tired from a week full of everything, and so they only mumbled hushed good nights as they made their way to their own rooms.
Katsuki slipped into Eijirou's before the redhead could close the door.
Eijirou started talking as soon as it was safely locked. "I don't— They can joke about it, I know we all cope in different ways, and I don't want them to give theirs up because of me. I don't even know, I've been trying to understand why this keeps bothering me so much when everyone else, including you, seems fine. I just—"
"Wish you'd been there. I know," Katsuki finished for him when Eijirou's voice faltered. He took his best friend's hands, guided him to the bed and made him sit. "It wouldn't have changed anything, Ei."
Eijirou shook his head vehemently, eyes glassy again as they tried to evade Katsuki's own. "You don't know that."
"I do, though." Katsuki walked closer, settled right between Eijirou's parted knees and took his face in his hands so that he wouldn't be able to escape. "I know for sure that if you'd been there, you would've jumped right in, and I would've been even more reckless because I could never let you run into such danger without me. I would've tried to protect you from protecting me, and it all would've ended exactly the same, except you would've been there to witness it, and I would never wish that on anyone, much less on my best friend."
"Denki was there," Eijirou whispered, a single tear making it down his cheek. Katsuki caught it with his thumb. "He came to me, after, did you know? Explained everything, because I asked him to. Sometimes I wish I hadn't, though," he confessed.
"Oh, Ei," Katsuki sighed. "Why have you never told me this?"
Eijirou shook his head some more, like he was trying to get rid of all the images his mind had apparently been conjuring up for the best part of a year and a half. "I didn't know how you'd react to him telling me and me knowing about it. I didn't want to upset you."
Katsuki shook him this time, like he did sometimes when they were in their hero costumes and he would grab Eijirou's mask in excitement. He found that the action worked well here, too, because it somehow got a tiny giggle out of the redhead — Pavlov's dog, and all that shit. "Listen to me, you dumbass. I don't give a flying fuck about the jokes, and I've gotten enough therapy by this point that I've come to terms with what happened to me, but if there's something I do care about, that's you.
"If you're not okay with the jokes, I will tell the idiots to drop them myself. There is literally nothing that matters more to me in this world other than becoming the best hero out there, and you. So," Katsuki said, locking his eyes on Eijirou's wide-open ones, "if you ever feel like this again, I want you to come to me, and we'll go from there together. Got it?"
Eijirou tried nodding, but Katsuki's grip on his face was so firm, he barely managed to move. "Got it," he replied, never looking away from Katsuki. "You're pretty good at the motivational speeches, have I ever told you that?"
Katsuki barked a surprised laugh. "I'm damn good at everything. Now, scooch over, we're having a sleepover."
"Are we, now?"
"Yeah," Katsuki nodded with conviction. "I'm gonna steal one of your shirts."
Eijirou's cheeks were warm, still locked firmly between Katsuki's palms. "Help yourself."
"Obviously." Katsuki didn't even try to move, though. He kept searching Eijirou's eyes, trying to find any lingering hurt that he could fight himself. "You good?"
"I'm better, yeah. Thanks, Kats."
Katsuki nodded. Then, he did something that he never thought he would ever do in his life — he bent down and, keeping Eijirou's face still, he let his lips rest on his forehead for a lingering beat.
Eijirou was warm under his mouth.
"You're important to me, Ei," he whispered, right on his warm, soft skin. "Don't forget that."
When he moved away at last, turning around to look for something to wear for the night, he caught Eijirou touching his forehead right where Katsuki's lips had been just a moment before.
And if he kissed him there again when they were cuddled up in the redhead's bed later, when Eijirou's head fit perfectly under Katsuki's chin and their limbs were so entangled that someone walking in wouldn't have been able to see where one ended and the other begun — well, that was between Katsuki and Eijirou, and no one else.
four.
Things didn't change much after that night, but that didn't mean that they didn't change at all.
Everything went on as normal. Class, work studies, patrol, homework, visiting his parents every two Sundays — it all kept going as it always did.
Katsuki and Eijirou weren't the same, though.
They'd always been pretty touchy with each other, but after that night, after Eijirou confessed in a whisper that he still saw Katsuki's dead body in his nightmares even when he'd never seen him in the first place, after Katsuki held him through the night and shushed him when he'd woken up from nightmares — they became worse.
Katsuki didn't stop himself from reaching out anymore. If he saw Eijirou being cute, if the thought that he wanted to touch him crossed his mind, he'd just… do it.
And Eijirou, the angel he was, never commented on it. Instead, he welcomed it with open arms — letting Katsuki bully his way into his arms on the common room sofa, smiling at him when he'd kiss his forehead or his temple, not even flinching when the cuteness aggression became too much and Katsuki started biting him wherever he could reach a patch of soft, exposed skin.
Their classmates barely reacted. The first couple of times it happened, they watched them like they were two weird creatures that had come out of the deep ocean. After that, though, they just seemed to accept it as another Katsuki-and-Eijirou thing, and everyone moved on with their lives.
The first person to actually bring it up was Tetsutetsu, one day when they were eating together in the cafeteria.
Eijirou had sat next to Katsuki, completely flush against him in the tight space, and then had given him a packet of spicy sauce. "I found these at the shop the other day, bought a few. They're on my kitchen shelf, I just grabbed a couple today when I remembered curry was on the menu and you always complain that it's not spicy enough."
Katsuki had watched him with what he was sure were starry eyes, and then he'd just… grabbed his face and started planting kisses wherever he could reach.
No one batted an eye, until Tetsutetsu said, "That's new."
Eijirou stopped giggling, sending the silver-haired boy a withering look. "Tetsu."
Tetsutetsu looked from Eijirou to Katsuki, then back again. He shrugged, then went back to his food. "I'm just happy for you, man. Everyone knows how long you've been pin—"
Katsuki didn't look up from his bowl of — very spicy, thanks to Eijirou — curry as the silver-haired boy broke off with a yelp.
No one else commented on it again.
five.
It shouldn't have come as a surprise when Katsuki exploded again, one day in the common room.
It was Class Movie Night, something they'd established soon after the war so that all of them could spend time together without the threat of hero work or school for at least one night a week, something to turn their minds off the horrors they'd seen and lived, a night where they could just be normal, dumb kids enjoying shitty movies and trash food.
Katsuki was bored, tonight. Every week, they all put their pick in a jar before Friday night, and when it was time, one of them would pull a strip of paper at random, and that would be the night's movie.
Katsuki wouldn't have said it to their faces, but most times, his classmates' choices weren't that bad. He wasn't very picky about movies, really, so he was usually happy enough with whatever.
And then there were movies like this one, and he kind of really fucking wanted to close his eyes and just sleep through it.
He fought his drooping eyes, though, and tried to keep up. There was always a discussion at the end of the movie where they would talk about it, and he wanted to at least understand a bit of what his classmates would say.
As he watched, a sudden weight fell on his shoulder. He looked to his right, and sure enough, Eijirou had been weaker than him — he was asleep, his head tilted at an awkward angle where it had fallen on Katsuki's shoulder, and the blond was approximately .7 seconds away from exploding because of how fucking adorable he looked.
He couldn't, though. Not when everyone was quiet, eyes glued to the boring movie in front of them like it was actually intriguing.
It was not. Eijirou's sleep-heavy breath on Katsuki's neck was proof of that.
Katsuki sat as still as he could. While he really, really wanted to explode from how cute Eijirou looked, his best friend was like a cat — he only slept this close to people he felt safe with, and the fact that he'd unconsciously chosen to fall asleep on Katsuki was like the best gift anyone could ever receive, and the blond would be damned if he accidentally woke him up now.
The movie droned on. Eijirou's deep breaths were warm on Katsuki's exposed skin. He wanted to both die and never ever move again, and so he stayed still, soaking up all of his best friend's warmth and trust and love and—
Oh.
Oh, fucking shit.
Katsuki had been so damn blind, hadn't he? It made so much sense, now that he had realized — all the times he'd felt like exploding while simply looking at Eijirou, how all his touches burned on his skin but never hurt, the way his heart sped up whenever the redhead would smile.
And while Katsuki knew that cuteness aggression could hit you from nowhere, he kind of really fucking wanted to bash his head against a wall as he realized that the worst cases of it came from looking at something that you loved deeply.
Or, in this case, from looking at someone. At his best friend, who had turned on his side and clung to Katsuki like a koala, throwing his legs on the blond's lap and circling his waist with his arms and holy shit, he was nuzzling his head on Katsuki's neck like the cutest fucking kitten to ever have graced the Earth—
He tried to muffle the explosion, he really did. He'd managed to keep his right hand from producing one, as it was resting on Eijirou's side, but he hadn't been that good with the left one.
While the explosion itself hadn't been too loud, it had charred the sofa, letting the smell of burnt fabric and padding fill the common room, and the muted noise of it had still caught every single one of his classmates' attention, rendering him a blushing mess in the dark room.
Eijirou snorted, and everyone looked at Katsuki with wide eyes. The redhead only got more comfortable, successfully hiding his entire face in Katsuki's overheated neck, and kept on sleeping.
"Man," Denki huffed a laugh. "You are so cooked."
And wasn't that just the understatement of the fucking millennia.
plus one.
It all came to an end a couple of weeks before graduation.
Actually, is wasn't actually the end — more like a new beginning.
When they found out, people assumed that it must have been some dramatic thing, like one of Katsuki's Howitzer Impacts, or a devastating earthquake.
In reality, it had been very simple. Easy, almost, and it had taken Katsuki by surprise in the moment. When thinking back on it, though, he'd realized that he shouldn't have expected anything different, actually, because everything with Eijirou had always been easy.
So, it was no wonder this had been, too.
They'd started packing. It was a slow process, because they still needed to be in the dorms for a few days and they couldn't exactly put everything in boxes already, but they'd begun nonetheless, and something in Katsuki had broken a little in seeing Eijirou's room slowly being emptied of everything that had been home for the last three years.
And Eijirou, oh — he'd been quietly putting his stuff away in the boxes Katsuki had meticulously labeled for him in black sharpie.
It wouldn't be the end of Katsuki-and-Eijirou. They were moving together — they'd found an apartment that sat snugly in a shitty building that was only a five minute walk from Mina and Tooru's apartment, seven minutes from Denki, Kyouka, and Hitoshi's, and a ten minute train ride from Hanta, Shouto, and Izuku's.
They'd never live all under the same roof, though, and Katsuki had been taking that harder than he'd thought he would.
He watched Eijirou as he folded a fluffy blanket. It was Spring, and the weather was already warm enough that they wouldn't need it anymore, but watching his best friend look down at it with a smile and then holding it close to his chest made something snap in Katsuki.
"You are so fucking cute," he whispered — not because he didn't want Eijirou to hear, but because he didn't want to break the quiet, bittersweet atmosphere they'd created.
Eijirou turned to him, an adorable blush flushing his cheeks, but he was smirking slightly. "Took you long enough to say it out loud."
Katsuki frowned. "You knew?"
"Of course," Eijirou laughed softly. He finished folding the blanket, then put it on top of the box before making his way to Katsuki. "You're not subtle, dude."
He could feel the fierce blush burning on his cheeks. "And you never fucking said anything?"
His asshole best friend shrugged, like it wasn't a big deal. "Knew you'd realize it on your own eventually. I didn't want to force you into something you weren't ready for yet."
Katsuki thought back to all the instances he'd almost blown up the entire school because of how adorable Eijirou had looked, and it hit him right in the face. "You've been doing it on purpose."
"Doing what, exactly?"
"All the—" Katsuki huffed, but couldn't stop a stupid grin from tilting the corners of his lips upwards. "The adorable looks, and the cute pouts, and just being so cuddly and touchy and never saying anything about how I was, too!"
Eijirou smiled innocently. "I don't know what you're talking about. I do, however, know that you like me."
Katsuki was going to take every single person in this building with him.
"The question now is," Eijirou said, taking the last step so that he could stand right in front of Katsuki, "what are you gonna do about it?"
And he looked so cute now too, with his blushing cheeks and confident grin and warm eyes, so Katsuki did what he had been great at as of late — he let himself get what he wanted, and that was Eijirou.
It had always been Eijirou.
Their first kiss was soft, a little insecure. Katsuki sure as hell had never kissed anyone before, and he didn't want to think about Eijirou with anyone else, so he didn't. He just let himself feel, finally taking what was destined for him — the one person who had always stood by Katsuki's side, never in front, and surely never behind.
From that day on, anytime Katsuki felt the cuteness aggression creeping up on him, he never stopped it again. He just leaned in, kissed Eijirou until he was a giggly mess, and then kissed him some more for good measure.