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Katsuki knew he had fucked up at the age of seven.
Don't get it twisted; Katsuki had fucked up way before that, but seven was when he finally wised up to how much of an ass he had been. Seven was also when Katsuki's old man and the Hag had sat him down in their living room with tears in their eyes and dropped a bombshell that had shattered his tiny little world.
Auntie Inko was dead.
Had been dead for a while, most likely, but they'd finally found her. Katsuki's folks had been looking for ages, since Auntie Inko stopped replying to their messages. It had been a fucking battle for them to get the cops to listen - something Katsuki later realised was because they stopped caring once they realised her kid was quirkless - but finally they found a couple of decent detectives who agreed to open up a search. Weeks later they'd come to Katsuki's mom with the news.
The funeral was small.
Katsuki had stood in his suit and nice shoes and glared at the ground so he couldn't see how empty the room was. There was his folks, and some friends Auntie had from work and school. Even a cranky old fuck who claimed to be an uncle or something. But there wasn't enough. Not nearly enough people to properly send off such an awesome and kind and pretty and just fucking awesome a person as Auntie is.
Was.
Fuck.
Worst of all to seven year old Katsuki, was the emptiness that should have been filled by Izuku.
It was like a hole in the rocks at the beach. The ones that just sucked everything down into a murky black nothingness and never let go. Only this hole was Izuku shaped. Katsuki never thought he'd miss the nerd's muttering all the time, but the eerie silence of Auntie's funeral really made it hit home just how much Katsuki wanted him around. Katsuki had stood by the grave of one of his favourite people in the world and wished desperately for there to be a mess of green curls tickling his nose as Izuku got snot all over his suit. He'd have sold his limited edition All Might figurine and done the dishes forever and never said a mean thing ever again if only Izuku would have appeared.
But Izuku never did.
The funeral was hard. Home was also hard. Katsuki had always thought of his mother as someone larger than life. Loud and pointy and unashamed of how she didn't fit in and everything he wanted to be, even though he'd rather die than tell her so. She had always bounced back after bad jobs or sad things. Even when her own mom - Katsuki's granny - had passed away, the Hag had made a speech at the funeral that had all the guests laughing and crying at the same time, then spent a night weeping into his old man's nice shirt before launching into a new fashion line of accessories for people with shitty joints in Granny's honour. With Auntie gone it was different. The Hag shuffled around the house like a zombie, wearing the same clothes for days and leaving sweat stains on the couch after sitting there for hours at a time. Katsuki had never seen her like this before, and it kinda scared him.
He thought that just like he had that Izuku shaped hole, sucking in all his attention, maybe his mom had another hole shaped like Auntie Inko.
School was the hardest. Izuku hadn't been there in a while, what with he and Auntie moving away months and months ago, but there had always been that thought in the back of Katsuki's mind that Izuku would be back sooner or later. Eventually they'd realise they liked it better back in Musutafu, and Izuku would be back in the seat behind Katsuki, muttering and scribbling his in stupid notebooks like he belonged. Now though, with the knowledge that Auntie was dead and Izuku was gone, Katsuki couldn't help but notice how quiet it was. How boring. How dull and useless his classmates were. Izuku was a Deku, quirkless and tiny and prone to crying if you sneezed too close to him, but he was still the only one who had even a chance of measuring up to Katsuki.
It wasn't until the little shit was gone forever that Katsuki realised that he was the only one who could keep up.
It had only taken three days after the funeral for Katsuki to land himself in the principal’s office for the first time. He sat, arms folded and fists clenched to keep from popping off. Next to him another kid sat, sniffling and teary and clutching their burned arm like it was going to fall off. Katsuki didn't know why he'd attacked the kid - well, kind of. He knew that he'd heard them making some shitty comment about how Deku had been gone for ages and they kinda missed watching the teachers and popular kids go off at the ‘quirkless freak’. He knew that after everything had gone kinda hazy and red. Knew that the next thing he remembered was a teacher screaming and running towards him as he stood, chest heaving and palms sweaty, looming over the kid who was also screaming and crying.
Katsuki’s old man had gotten called in to talk to the principal. He made one hell of an image as he came into the office. Katsuki had never seen him look like that before, all stern and shit. Katsuki sat quietly, fists clenched, as his dad quietly but ruthlessly tore the whole school a new one. Katsuki didn't get in trouble. The whole thing was blamed on 'emotional stress' and when the other kid's mom tried to complain Katsuki's old man asked Katsuki why he'd lost his cool and Katsuki told him.
His dad made both the other kid and his mom cry without raising his voice above a whisper.
"I just want to make sure I understand correctly," he had said. Katsuki knew that tone and sank into his chair more. "My son, who has a history of quirk-related behavioural issues, has just come back to school after going to the funeral of his aunt - who was like a second mother to him - and is trying to process this immense stress as well as process the knowledge that his childhood best friend is missing, presumed dead. And you want to punish him for reacting to someone else saying they want to see said missing-presumed-dead child beaten up in front of him, re-traumatising him? Is that right?"
Katsuki watched as the lady tried to sputter out a response, but his dad wouldn't let her finish a sentence. The rest of the meeting went quickly. The other kid still hadn't stopped crying by the time their mom pulled them out of the room, and Katsuki couldn't help but compare that to Izuku. Izuku cried, sure. All the time, about any stupid thing. But when Katsuki exploded him he would always stand right back up, lip wobbling but eyes fierce. He never complained, never screamed like a baby. His tears flowed down his cheeks but he smiled and told Katsuki he was cool anyway.
Katsuki missed it. Missed him.
His old man had stayed quiet as they walked to his car. They got in but the car didn't turn on. Katsuki looked up to see his dad watching him silently. Eventually he spoke.
"Kats, I'm sorry you had a bad time at school today," he said slowly. "But I think we have to talk about what happened."
Katsuki nodded. He hadn't liked losing his shit like that. He had no control, and that didn't feel awesome. If he was being totally honest, it was actually kind of scary.
His dad drove them home. Katsuki dropped his school bag in the middle of the lounge room and crawled onto the couch, tucking himself under the Hag's arm where she sat in the same place she'd been when he left that morning. The old man came and sat with them too, and the Hag blinked and came back to herself.
"Kats? Masa?"
Her voice was rough like gravel. Katsuki hated it.
"Katsuki had a bit of an altercation at school today," his dad said.
"Did you kick the other kid's butt?" Katsuki smiled a little at his mom’s words. That was the most Hag like thing she'd said all week.
"Always," he replied.
"Which is the problem," his dad said. Katsuki watched his parents' faces as his dad explained what happened. His mom looked confused, then angry, then a little scared. She looked at Katsuki.
"So, you really don't remember?" She asked. Katsuki shook his head.
"I didn't like it," he told them. "I don't like not knowing what the hell I did."
Katsuki learned what therapy was that day.
Katsuki learned to like therapy over the next few months.
It was a slow process, and there were days where Katsuki still lost his shit on another kid and came back to himself with fuzzy memories and a trip to the principal. It took four more meetings with the principal for Katsuki’s folks to pull him from that school and put him in one designed to cater to kids with quirks that affected their moods. Katsuki had hated the school at first. It was a dinky little place that consisted of three different units in a warehouse facility, conjoined by stupid colourful strips of paint on the tarmac between the buildings. The floors were a little soft like a dancing studio and the walls were covered in messages that were supposed to be inspiring but that Katsuki thought were stupid as hell.
There were no desks or chalkboards. There were no gyms or cafeterias or computer labs. There were no fences or separation from the other businesses in the area. There was even some weird old dude who used one of the warehouse units near their classrooms as a storage space. There were mornings where Katsuki would get dropped off just in time to see the dude walk from his shitty camper van in the parking lot to his crammed-to-fuck unit in a bathrobe and slippers.
It was barely a fucking school at all.
But, a week or two in one of the other kids had a meltdown. Literally. Their quirk made them all goopy when they got too stressed or sad, and the kid dropped their juice box, spilling it on the floor. The kid started crying, then sank to their knees, then kept sinking. Katsuki stared as the teachers quickly shoved the rest of them to one side and scooped the kid up with calm words and a bucket. The kid was making a scene too, screaming louder than the Hag when her favourite soccer team lost and smacking their drooping face into the floor. By the time the teachers had gotten them scooped up and calmed down, the kid had destroyed two square meters of their special soft floor, three staff uniforms and a laptop.
There was no punishment. No harsh words or judgemental looks. There was only kindness and calm.
A few days later Katsuki had a meltdown himself. The whole school kinda just lumped together for a lot of classes, all the ages in the same room on their own laptops working on their own shit. It was nice, not having to wait for dumb babies to catch up. Katsuki had been powering through math worksheets and puzzles for three days, on a roll. He’d been aiming to get 100% in every quiz, because he was best. He’d been succeeding too. The Hag had been practically glowing with pride.
So when Katsuki finished the last quiz of the topic and hit submit, only to get back a 97%, he froze. That couldn’t be right, he was the best. His breathing had picked up, and everything had gone fuzzy, and before he knew it he was losing his shit. He screamed and threw the laptop into the wall, shattering it. His palms got super sweaty and then he was exploding everything within reach, screaming and cursing with tears in his eyes. How could he have fucked up like that? Useless!
After a while Katsuki became aware of the fact that the other kids were calmly waiting to the side, like he had when Goopy had their meltdown. Then he noticed that he was being surrounded by three teachers and that old dude from across the road, all of them standing two steps back but talking to him softly, encouraging him to breathe. Katsuki noticed then that he wasn’t breathing.
He tried to breathe. It was too fast, but with the teachers there not looking scared or angry Katsuki was able to slowly get himself back together. Just as he was really starting to calm down, one of the kids to the side sneezed, and Katsuki exploded again.
The old dude lunged forward, wrapping him arms around Katsuki and taking the brunt of the explosion to the chest. Katsuki yanked himself out of the grip and skittered back a step. He’d fucked up again, he was going to get kicked out of this school too. He’d hurt –
The old dude was fine. There was no mark under his ruined shirt, just a slightly shiny look to the dude’s skin. The shock knocked Katsuki fully out of his episode, and the teachers tugged him to the tiny staff room to clean him up and get him water.
He learned then that the old dude was called Tetsutetsu Takeo and was employed by the school to help with kids like Katsuki. Katsuki hadn’t done anything wrong. There was no punishment. No harsh words or judgemental looks. There was only kindness and calm.
Katsuki decided then that maybe the school was a little bit awesome.
Old man Tetsu was also a little bit awesome.
Katsuki had talked to his therapist about what set him off, and then talked to his therapist and his parents about fear of failure and pressure. He’d learned like seven different breathing exercises and a few sentences to say to remind himself that it was okay if he wasn’t the best. He could be the best at some things, but didn’t have to be the best at everything all the time. It made a little tickle of bad feelings that sat under his lungs fade a bit, which was awesome.
He also started chatting more with the other kids, and the teachers, and old man Tetsu.
Before he knew it, Katsuki was thirteen years old. He was a lot calmer than he was as a little shit. Therapy and shit had worked pretty well. He was almost a whole grade ahead in school, and still kicking ass. He had an honest to God friend in Goopy (whose name was actually Noguchi Yasu but had only laughed when Katsuki called them by the nickname). Everything was going pretty well, except for two things.
One of those things, the gap left by Izuku’s absence, was something Katsuki couldn’t do anything about. It pissed him off, but his therapist assured him that it was okay to still have a lot of feelings about it all, so long as he reminded himself that there were other things he could do something about and didn’t wallow.
So Katsuki focused on the second thing; he still wanted to be a hero.
He loved his school; he could admit that by now. His parents had made the right call all those years ago. But he still craved admittance to UA with everything he had. His grades were good – great, even – and his record had a little note about his quirk that meant all the meetings with the principal of his old school wouldn’t work against him. His quirk was under way better control too. The school had special permissions to train the kids in quirk use and control, considering why they were all there to begin with, and Katsuki had taken that permission and run with it. Explosion was a fine-tuned tool in Katsuki’s arsenal; meticulously honed and perfected.
The issue was that that wasn’t enough for Katsuki. He had to be certain beyond a shadow of a doubt that he would ace the entrance exam. He needed to be stronger, smarter, better, so that he could be a hero. So that he could fulfil his and Izuku’s childhood dreams even if Izuku wasn’t there to succeed with him.
After three meltdowns in two weeks, old man Tetsu had yanked Katsuki aside and demanded to know what the fuck was up. Katsuki, having spent five years learning all about the retired army soldier and kind of looking up to the cranky old bastard, told him everything. Who Izuku was, what Katsuki had done to him, how Auntie had died and they hadn’t learned about it until way too late. How Katsuki wanted – no, needed – to be a hero for both of them. How there were still days when Katsuki felt convinced that Izuku’s disappearance was all his fault.
Old man Tetsu had listened silently, eyes dark and face stern even with the fuck-tonne of laugh-lines he had. Then he stayed silent for a good three minutes after Katsuki talked himself out. Then he sighed and told Katsuki to see him the next day and stomped back to his warehouse.
Katsuki had walked straight up to him the next morning only to be handed a diet plan and an exercise routine.
“You’re young, but there’s just enough meat on your bones for this to be worth it if you put in effort,” Tetsu had told him. “Welcome to army bootcamp, brat.”
Katsuki threw himself into the training. He got up and ran around his neighbourhood at five every morning. He ate mountains of plain rice and lean meat and vegetables, and then burned that shit with a brutal exercise routine that left him exhausted and aching every night. Katsuki fucking loved it. His episodes went down to almost nothing, and his brain felt blissfully empty in a way it never had before.
“Why didn’t you get me on this shit sooner?” Katsuki had asked old man Tetsu during one of their boxing sessions. Tetsu punched Katsuki in his helmeted face with a mitted fist.
“You were too scrawny,” he’d grunted.
Katsuki could see where he was coming from, but still wished that he’d had this kind of outlet sooner. Maybe then Izuku would still be around. Tetsu punched him again.
“Focus on the now, brat,” was the wisdom the old man delivered along with a beating.
Seventeen months of training saw Katsuki to the UA entrance exam. Seventeen months saw Katsuki get first place in the exam with 85 villain points and 3 rescue points for yanking some idiot out of the way of a robot. Seventeen months saw Katsuki saying goodbye to the school that had changed his life. He’d thanked the teachers, ruffled Goopy’s microbraids, and kicked at old man Tetsu’s shins when he pulled Katsuki off his feet and into a massive bear hug.
“Don’t be a stranger, brat,” Tetsu said. Katsuki grinned.
“I’m the first kid from this shit heap to make it to UA,” he said. “I’ve made fucking history! You can bet your ass I’m gonna be back, I gotta show off all my cool gear and shit, right?”
“Right,” Tetsu laughed. “Now fuck off and save the world, brat.”
And Katsuki did. He walked out of that school and straight into the hero course at UA, feeling like he could take on the fucking world. He was going to be a hero. He was going to make Izuku proud.
He was going to dropkick that glasses wearing fuck that kept yelling at him for not being proper enough.
After so many years learning at his own pace in a school that didn’t even have fucking desks, regular high school was a hell of a thing to get used to. The uniform was stiff and inflexible and very different from the t-shirts with the school logo on them and sweats he was used to. The desks were tiny and it felt like Katsuki had no room to spread out and process his shit. The silence was weird too. There was no music, no chatter, no semi-regular meltdowns from the various kids. Everyone was so put together and preppy and boring.
He missed old man Tetsu. He missed Goopy.
But he wasn’t gonna let UA scare him off, not after all the work he put into getting there. So he nutted up and fucking aced Aizawa-sensei’s fucking first day test, and then he fucking aced the first few days of classes. He hadn’t scared anyone off, and he hadn’t had a meltdown, and he was feeling pretty good all things considered, Except Four-Eyes and his pretentious whining, of course.
Except the kid three seats behind him with the green hair that made the Izuku-shaped hole in his life burn.
The kid was a fucking nutcase. He’d actually jumped into one of Katsuki’s explosions to get a better score on the first day, and then fucking re-engineered a whole ass cannon to do it again. He’d sassed Four-Eyes three days in a row with a calm smile that did not match his feral energy and was all the weirder for it. He had green hair and green eyes and was fucking built for how short he was.
Worst of all? His name was fucking Midoriya Izuku.
There was a good thirty seconds where Katsuki had felt his heart leap into his mouth, because surely there was no way that there was two ‘Midoriya Izuku’s in Japan, especially not two the same age. But the kid looked him straight in the eye and there was no recognition at all. None. There was a slight tilt to the head, like the kid was trying to figure out a puzzle, but there was no smile, no tears, no indication that this was Katsuki’s Izuku.
Katsuki’s Izuku was surely dead by now, after eight years.
Katsuki had cried into his pillow for a night or two, but then gotten his shit back together. If his Izuku was really gone then he definitely had to kick ass and become a hero. He had to prove himself.
And then their first hero lesson happened. The perfect opportunity to show what he could do.
He got paired with Four-eyes, against the wrong Izuku, but it was fine. Katsuki was fine. He’d just fucking ace this class like he had all the others. It started out great, he had wrong Izuku on the ropes while Four-Eyes handled the two Bird Brains. He was hunting down his opponent exactly the way he was supposed to, using tips and tricks from old man Tetsu to keep track of wrong Izuku – and wasn’t he an elusive fuck?
But then everything went horribly, horrifically wrong.
Wrong Izuku was good, and Katsuki got angry. Katsuki lost control.
Not like a meltdown. Way, way worse.
Katsuki had designed his hero costume with Izuku’s old scribbles at the forefront of his mind. Even almost a decade later the nerd’s ideas held water, were clever enough to incorporate. He’d especially liked the grenade-like gauntlets that would hold his sweat for bigger explosions. But he’d drawn them too big, and he’d sweat more chasing wrong Izuku than he’d thought. So when he let off a blast with the gauntlets everything went to shit in about two seconds flat.
Before he could figure out what was happening, wrong Izuku had hauled him out of the now crumbling building and left him on the grass nearby. Then the crazy fuck went back in and crashed through a wall two stories off the ground about seven minutes later carrying Four-Eyes and Bird Brain while Katsuki curled in on himself and had a panic attack.
He hadn’t lost control like this - without going fuzzy, all his own fault – since he was six. Since he’d blasted Izuku away instead of taking the helping hand offered to him. Since he’d sent away his best friend to die alone in the cold like Auntie Inko.
He’d fucked up.
He’d fucked up, and this wasn’t his old school with Goopy and Tetsu and the simple understanding of the teachers there. This was UA. The best hero school in the country. The most exacting and exclusive school in the continent. Would they treat him like they did at Aldera primary? Would they kick him out?
He’d deserve it, but he needed to stay. He still needed to be a hero for his Izuku.
Katsuki had ended up in the infirmary with a headache and an appointment with the on-campus therapist. He went without protest, and even explained his mental health plan and school history to Hound Dog without prompting. He’d do anything to stay.
But there was no punishment, no judgement. Once he’d explained himself, Katsuki was set up with a different appointment with the support course to alter his gauntlets and endured a long moment of staring from Aizawa-sensei, then it was like nothing had gone wrong at all. The only evidence that Katsuki had fucked up was the crazy green haired kid’s new look, and the new lack of conflict between he and Four-Eyes. There wasn’t really any conflict between Katsuki and Four-Eyes anymore either. That ship sailed when Katsuki demolished a building and Four-Eyes lost the stick up his ass within four days of each other.
The only thing left was for Katsuki to nut up and apologise to wrong Izuku for almost blowing him up.
He’d managed to get the kid to agree to follow him to an empty corridor during their lunch break, but got stuck once those green eyes were staring him down. The resemblance to Katsuki’s Izuku was too much, and it made Katsuki want to rip his skin off and scream. He stood in front of wrong Izuku, hands shoved into his pockets and glaring at his indoor shoes. Katsuki opened his mouth. Closed it again. Swallowed heavily. Made a scoffing sound at the back of his throat. Finally looked up at wrong Izuku.
“Thank you.”
After that the words were easier. They were stilted to fuck and probably didn’t make a whole lot of sense, but Katsuki was able to spit them out at wrong Izuku’s feet. The green haired kid asked some questions, answered others, but mostly let Katsuki speak, explain himself a bit. His eyes tracked Katsuki’s every move, but in a way that made Katsuki feel safe more than antsy. It was a weird feeling. He wasn’t sure if he liked it.
“How’d you like the katsudon?” he asked, desperate to shift away from his own vulnerabilities. Wrong Izuku let him have the deflection.
“Pretty good,” he replied. “Good crunch.”
Katsuki stared at him for a long moment, squinting. It hurt a surprising amount to hear someone that looked so much like his Izuku act so alien. Wrong Izuku stared back, raising an eyebrow when Katsuki stared for a moment too long.
“Sorry,” Katsuki bit out, hunching his shoulders. “I was waiting for you to say katsudon was your favourite.”
“Why?” Wrong Izuku asked, head tilting like a curious puppy. Katsuki frowned.
‘Because it was my Izuku’s favourite’ was there, on his tongue, so close to slipping out into the space between him and this painfully familiar stranger.
“I don’t know,” Katsuki said instead. Wrong Izuku looked at him for another few seconds, then shrugged and clapped Katsuki on the shoulder as he passed to go back to the cafeteria.
“Well, don’t take too long remembering, we have class soon,” Wrong Izuku offered a grin and waved as he walked off. “See you soon, Kacchan!”
Katsuki froze. Wrong Izuku froze. Both twisted to stare at each other, confusion and recognition on both of their faces. Before either could speak, an alarm screeched out over their heads. Katsuki winced, his palms crackling against his will at the sudden sound.
“The fuck is happening?” Katsuki yelled over the noise.
“That alarm means there’s been a security breach,” Wrong Izuku told him, looking at the ceiling for some fucking reason. “Stay here, the halls are gonna become a death trap.”
Katsuki watched, unable to speak or move, as the crazy green haired fuck jumped straight up and caught the vent cover with his fingers. As wrong Izuku swung back and then launched himself up and into the vents, Katsuki just stared. Then he shook his head and went to go see what the fuck was up with the alarm.
Later, when everyone was back in class, Katsuki couldn't help but keep sneaking glances at his classmate. There was so much that was familiar, even though there was much that made no sense. The hair, the eyes, the freckles.
The smile was different. So was the sass. And the upper body strength.
And yet, Katsuki thought, there was too much that was the same to be coincidence. The resemblance was too close. Katsuki may have genuinely found his old friend after all these years. His heart was in his mouth again.
How the fuck was he going to apologise?