Chapter Text
The summer after middle school, Bakugou Katsuki had a run in with a villain. He had already sent in his application to UA, already knew he’d get in, but he was still just a boy, just a kid, not ready yet to take on something like that on his own.
The villain stole his quirk.
Katsuki’s memory of it all was fuzzy at best, but he remembered the sparks in his palms sizzling down to nothing, remembered the feeling: like he’d had electricity in his blood but it was all slowly being sapped, leaving him- leaving him quirkless.
It was more than just his quirk, though. Without his quirk, UA regretted to inform him that he was no longer suited for the academy’s hero course. It was his power, his future, his ambition and passion, his pride: all gone in one fell swoop.
And then, to make matters worse, as he watched the next batch of UA students roll in, who did he see but Midoriya fucking Deku, joining the ranks with- with a quirk of his own. Deku, the quirkless crybaby, was on his way to become a hero, and Bakugou Katsuki, who had known his destiny since before he could blow up a fucking acorn, was left in the dust. Somehow, while he wasn’t watching, Deku had stolen his dream.
The more he watched, the more things seemed to fall into place. Not only did Deku have a quirk now, but it was a familiar one. Too familiar. It was All Might’s quirk, Katsuki was sure of it.
Everything Deku had ever wanted had fallen into his hands, and Katsuki-
Katsuki spent months and months resenting Deku and not much else, because the resentment kept the crippling feeling of ineptitude at bay, but after watching All Might lose his powers on national television, the shock forced Katsuki’s eyes back on Deku in a different way.
Katsuki saw Izuku who had inherited a quirk he couldn’t handle, a quirk that destroyed his body as he used it, a quirk that came with a world of responsibility no child should have to bear.
He saw Izuku who finally had friends (good ones, not like Katsuki) but had just lost his hero. He saw Izuku who put everyone else first, who was too- too strong, too stubborn for anyone to talk sense into, who was reckless and careless with himself.
He saw Izuku who had all that power, who helped so many people, and who still named himself Deku, like he was just a useless wooden doll instead of a hero who saved people.
And Katsuki found something new to keep him going; if he couldn’t be a hero himself, he was gonna make damn sure Deku was the best fucking hero he could possibly be.
Katsuki had always been above average in his studies, but he threw himself into them more than ever, applied to the top support schools and got in everywhere (studied Izuku relentlessly from afar, brainstorming already just how best to work on him).
Katsuki finished high school in two years, because he knew Izuku would be a hero straight out of the gate, while he would have to go get a degree, and he finished his university studies in two years too, only putting him one year behind Deku instead of four.
By the time he graduated, he was known as something of a prodigy in the support world, which was complete bullshit. There was nothing prodigious about how he’d worked himself to the damn bone trying to keep up with Deku before the idiot destroyed himself.
But it meant Katsuki had his pick of jobs, and when he applied specifically to work on hero Deku’s suit and gear, the team was ecstatic to have him, even if he was the youngest one there by far.
Katsuki implemented a whole slew of changes in the first few months, rapidly but subtly making Deku's gear as good as possible, always trying to find ways to keep improving it.
And then, after a year and a half of working there, Izuku came to the department for the first time, his respirator cracked beyond repair and in urgent need of replacing. When he saw Katsuki, he froze.
Katsuki hadn’t seen Izuku up close like this since they were barely fourteen, and now they were twenty and Izuku was a fucking pro, fucking big, and right fucking there, and Katsuki didn’t really know what to say.
After so many years, Katsuki had… come to terms, sort of, with losing his quirk, but he couldn’t deny the humiliating irony of it all now that they were both standing there: Izuku’s eyes an almost electric green, his shoulders broad and hands scarred; and Katsuki, dressed in stained jeans and a tee shirt with the sleeves rolled up to his elbows, thick leather gloves on his hands and thin wired glasses on his face.
Katsuki planned to work on Izuku's gear until the idiot retired or died, but he’d never actually prepared to meet him again. Maybe he’d thought that someday, he’d be good enough that people recognized him, maybe he’d win some awards or something and Izuku would see him then.
He didn’t think that it would happen at two in the morning when Katsuki was the only one left working, smudged with grease, hair pushed back from his face with a headband, blue-black bags under his eyes.
Katsuki’s first reaction to embarrassment was anger; it always had been and, no matter how much he’d tried to work on it over the years, it still was. But when Izuku finally stammered out a familiar “Kacchan?” in a much less familiar voice, Katsuki didn’t let himself bite back.
He held his tongue until he knew that he wouldn’t open his mouth and say something shitty, and when he was finally ready, he took a deep breath and sat back. “Midoriya,” he greeted. “What do you need?”
The name felt wrong on his tongue, but his options were limited. Even if it was his hero name, Deku was off limits, at least from Katsuki's mouth. and Izuku- Izuku was far too much for practical strangers, which was basically what they were now. So Midoriya it was.
Izuku stared at him for a moment, eyebrows furrowed, mouth open like he wanted to say something- But then his face just… shuttered off like a switch had flipped, and he held out his respirator. “It broke during combat, but there’s a villain with a gas quirk in Toshima, so if you could fix it quickly…”
Katsuki couldn’t help the half amused huff that escaped him as he took the outstretched gear. “Let me guess, you’re only here because they wouldn’t let you go without fixing this?”
Izuku had the decency to look chastised for the better part of a second before he straightened up with a cold look on his face. “Every minute we waste talking is time I could be saving lives, Bakugou-san. Please get to work.”
Oh, ouch. In the grand scheme of little cruelties Katsuki had dished out in his life (and the many he’d received after losing his quirk), he hadn’t expected that his own name would be the one to sting so badly.
“Right,” he muttered, only giving the respirator a cursory glance before tossing it aside and moving over to rummage through the drawers of other projects he was working on. All for Deku. “It's not exactly ready for the field,” he explained as he pulled a prototype out of its box along with a few parts he still needed to add. “Give me twenty minutes, you’ll be good to go.”
“You have ten,” Izuku said after a second, and Katsuki didn’t even bother glaring at him because that would waste precious seconds. If Izuku said ten, he meant ten, and he’d be leaving whether the mask was done or not.
Katsuki had ten minutes to make sure that Izuku didn’t fucking kill himself running out there unprotected. That was what he was here for after all, wasn’t it?
He worked as quickly as he could without sacrificing the integrity of the gear. He added an extra gas filter, as well as two small oxygen vials on either side in case of emergency, though they’d only be good for two or three deep breaths. There was no time to tune up the built in photosynthesizer Katsuki had been working on to recycle Deku’s own breaths into fresh oxygen, but maybe he’d get to that some other day. For now he made sure that the raw edge of the metal wouldn’t cut into Izuku’s face, and that the mask wouldn’t slip off in the fight.
Izuku stood like a statue behind him, stock still as he watched Katsuki work with single-minded determination. At the ten minute mark, he suddenly shifted, leaning over Katsuki’s shoulder to see better, and Katsuki was shocked out of his focus by the realization that holy shit, Deku was big; big, big, big; and right behind him, curled around him, and it was Deku; DekuDekuDeku-
“Back the fuck up,” he croaked, muscles freezing at the proximity. “I have gloves on for a reason, this shit’s not safe.”
Izuku didn’t move for a moment before taking a step back. “I think I can handle it,” he said dryly. “I'm sure I've survived worse.”
Katsuki could probably list every worse encounter Deku had had in his career, and if he couldn’t, that one magazine spread with him shirtless, scars on full display, would be proof enough. But whatever.
“Good for you,” Katsuki muttered, snuffing out the old spark of jealousy at what he could’ve had. If he’d never lost his quirk, he would be just as battered as Izuku, if not more. They’d compare scars and Katsuki would win with something gnarly and wicked like a tear right across his chest.
But Katsuki’s scars were limited to his hands and arms from his work and… and stuff. They weren’t the kind of scars you showed off, not the kind of scars that proved how strong you were.
“Here. Don’t do anything stupid, I wouldn't give this to you if I didn’t know you’d go off without it otherwise. If you see the red light here,” he touched the top edge of the respirator, right where it’d blink in the corner of Deku’s vision, “it means the filter’s not working. Press this button and it’ll stop outside airflow. You have enough oxygen for two deep breaths, so use them to get to clean air if you have to. Got it?”
When he glanced up, he found Izuku staring down at him instead of the respirator, his eyes darkened with a troubled frown. When their eyes met, he snapped out of it and took the gear from him, smoothing his features into something unreadable.
“Got it,” he said, flipping the mask carefully in his hands. When he looked back at Katsuki, his expression was a little less closed off, a hint of the Izuku Katsuki remembered shining through. “Thanks.”
Katsuki had been making support gear since before he even graduated, some of his earlier patents selling before he even started his degree. No one had ever actually thanked him for it. He stared dumbly as Izuku began to leave, but then he remembered-
“Shit, Deku, wait. Take these.” Katsuki snatched his own safety goggles from his work bench and tossed them over. Izuku caught them easily with one hand. “And bring them back after. The respirator too.”
There was only so much Katsuki could do anymore with no quirk, no way to help. He could only make gear and send it off, and then hope that it came back in one piece (hope that he came back in one piece).
Izuku nodded firmly after a moment of silence, and then he was off. It was only when the door shut behind him, leaving Katsuki alone once more, that he realized he’d called him Deku again after all.
Katsuki had just been finishing up some work when Izuku stormed in, but he ended up staying longer than he’d planned to. He didn’t… He didn’t want to go home yet, not when… not when he didn’t have his goggles back, didn’t know how his respirator had held up.
He was working on palm sized thrusters to help Deku maneuver quickly when using Float, but at some point, he must have drifted off over his work bench, because the next thing he knew, he was startling awake to a hand on his shoulder.
Sluggish and disoriented, Katsuki jerked upright and away, his chair spinning him out of reach before he even knew what he was running from. When his eyes focused, he found Izuku blinking down at him, head tilted curiously, cautiously.
“Oh,” Katsuki sighed, slumping back in his chair, “it’s you.”
“Mm. You know, I heard you do work with some pretty dangerous stuff there, maybe it’s not the best place for a nap. Bakugou-san.”
Katsuki dragged his hand over his face, too tired to play the part. “Don’t call me that,” he muttered, rolling his chair back over to clean up. There was no way he was getting anything else done tonight. This morning, actually, he realized when he saw the time. “Did the mask work?”
Izuku was silent for a moment. Then he carefully set the respirator and goggles down on an empty space. “Yes, it was perfect. Thank you, Ka- Katsuki-san.”
Katsuki froze before talking himself down and moving on. Izuku didn’t need to call him Kacchan, it was fine. “And everything else?” he asked, tidying up the last of his work. “Any issues?” He turned and gave Deku a once over, cataloging every scrape or spot of blood, every possible sign of damage. To Deku’s suit, of course.
Izuku shrugged, looking oddly smaller than his big frame. “Pretty good. There are a few things, but I'll just put them in my monthly check in for whoever needs it.”
Katsuki rolled his eyes and slammed his last drawer shut a little harder than intended. “I'll save you the trouble: I need it, because I make your gear, Midoriya. The sooner I know what’s wrong, the sooner I can fix it, and the less your chances of martyring yourself to some shitty villain.”
When Izuku responded, his voice was dark and serious, none of that awkward politeness present. “I'm not the useless kid I used to be, Ka- Katsuki-san. I have a quirk. I'm a hero now, a good one. I don't need you looking down on me anymore.”
Katsuki was frozen in his seat, back still turned to Izuku, and he sucked in a ragged breath. Then he pulled off his thick gloves and laid them neatly to the side. He raised his hand to the side, palm up like he always used to do. And then- Nothing.
“I’m the deku now,” he said quietly, the humor in his voice still too acrid and bitter to come easily. He didn’t give Izuku a chance to speak, standing up and collecting his things without looking at him straight on. “I know you’re a tough bastard. That doesn’t mean I have to sit around and let you test your own limits ‘til you fall apart. I know you can do your job, but I can do mine, too, and that’s keeping you safe.”
He shouldered his coat on and walked past Izuku without meeting his eyes.
“Don’t wait for the check in. If there's something wrong, I'll fix it. And I’ll have a new mask for you by the end of the week, so don’t do anything stupid until then. Good night, Midoriya.”
If Izuku answered him, Katsuki didn’t stick around to hear it. He stepped out into the cold night and pretended his shaking hands were from the biting wind.
The next day, Katsuki went into work late and found a list sitting on his desk. He looked it over with a scoff—it looked like Izuku’s handwriting hadn’t improved since middle school. Katsuki wondered if he still kept journals like he used to. From the thorough notes explaining his issues with his current costume, Katsuki wouldn’t doubt it.
He was satisfied to note that there didn’t really seem to be anything wrong with his current gear beyond a few minor issues that were hard to anticipate without actually testing the gear in person, but Izuku had a lot of suggestions and ideas that Katsuki… didn’t hate. Some of it was stuff Katsuki had thought about before and either dismissed or already started working on, but some of it came from Izuku’s unique perspective as the only one who knew how his quirk felt, what specifically he needed in order to help him perform at his best. If they didn’t have quite so much history between them, Katsuki would march up to Izuku’s desk and talk everything out with him instead of just reading the list over.
But things were better this way. Katsuki didn’t know how to feel about Izuku knowing about him—knowing he worked for the agency, knowing he was the one who made his gear, knowing that Katsuki (Kacchan, the bully-hero he’d spent his childhood chasing) was the quirkless one now—but it was better if they didn’t actually interact much. Easier.
Katsuki would do his job just as well regardless, and Izuku wouldn’t have to- to see him. Katsuki hadn’t earned his attention—not when they were kids, and certainly not now. Not yet.
But he set the list to the side for now. Deku needed a respirator, and he’d left some feedback on the prototype he’d used the night before, so Katsuki had work to do.
As always, Katsuki got lost in his work, only pausing to eat when one of his coworkers, an older Indonesian woman named Kemuning, interrupted his work with a stern glare and a tap on her wrist to let him know he’d been at it for too long.
A quick lunch (dinner? … dunch?) in the agency cafeteria, and Katsuki was right back to his bench to keep working. He never noticed when other people started to leave, though Kemuning always threw a snack at him on her way out, but eventually he was alone again.
And then, at some point, he was suddenly not alone anymore.
“Fucking sh- What the fuck,” he spit, startling once again when he happened to look to the side and catch Izuku standing behind him, watching him work. He pressed a hand to his chest to calm himself down. “How long have you been there? You don’t make noise when you move now, hah?!”
Katsuki didn’t use to startle easily. When he had a built in offensive defense mechanism, there was nothing to worry about, nothing he couldn’t handle even as a kid.
It turned out that his generally unlikeable personality was one thing when he was at the top of the food chain, but when he was suddenly and very vulnerably right at the bottom, it was much more problematic. For him, that was.
Katsuki didn’t like being snuck up on anymore. Not that Izuku would have any reason to know that.
“Sorry,” Izuku said, not sounding very sorry at all, “habit. It's just been a few minutes. That’s my new respirator?”
Katsuki grunted an affirmative, picking up the main body off it and holding it out. “I'm making sure it’s more durable. If it does break, it should crumple or break into big pieces instead of shattering. Too dangerous by your eyes and other face-holes.”
Izuku hummed appreciatively, and Katsuki's eyes widened when there was a sudden spark of viridian lightning around Izuku’s hands. “Oh, nice,” he said, as if he hadn’t just powered up One For All right in front of Katsuki's face. “Seems tough.”
Katsuki snatched the mask back and spun around. “If it can’t even handle your own quirk, I wouldn’t fucking give it to you.”
“The last one broke because of me,” Izuku said shamelessly.
“That's because you used three quirks at once,” Katsuki snapped. “You landed yourself in the ICU for a day and a half. If your own damn body can’t handle that, why should a piece of fucking gear?”
Izuku was quiet for a moment. “I only have one quirk, Katsuki-san.”
“Bullshit,” Katsuki sneered, opening a panel on the mask to check the filter layers. “I figured it out ages ago. You and All Might, and the different abilities. All Might’s mentor was Float. I figured some of the others out, but I couldn't find information on all of them. I'm not sure how it works still, but something about the quirk lets it accumulate and transfer. I don't know how people haven’t figured it out yet.”
“I guess because they didn’t know me as a quirkless deku,” Izuku murmured after a moment. “No one bothered to think about it so hard. You’ve always been observant, though.”
Katsuki clicked his tongue and didn’t answer. It was nice to have some confirmation for his theory. It was less nice to hear quirkless deku out of Izuku’s mouth. “Whatever. Why are you here?”
Izuku shuffled awkwardly, stuffing his hand in the pocket of his green Deku hoodie. Katsuki had one at home too, but only because the agency gave him free Deku merch all the time.
“I just wanted to see- see how it’s coming along. I also thought maybe you’d want to test things out on me, see how they are in action instead of just sending them straight into the field. If you wanted.”
Katsuki paused. Sure, that would be fucking helpful but… that would also become a lot of time spent together. “I don't have anything ready for that kind of testing right now,” he said carefully. “I'll… think about it.”
“Sure,” Izuku said, a little too chipper. “And, um. Did you get the list I left?”
Katsuki raised an eyebrow at him and tapped the papers on the side. “I did.”
“So, uh. What did you think? It’s not that I don’t think your gear is good, it is! But I thought maybe some changes…”
“Yeah,” Katsuki agreed, cutting Izuku off before he mumbled himself stupid. “Some of it just won’t work, I've thought about it before, but there were some decent ideas in there. Some good ones, too, though I'd already had them.”
“You had? So you’re-”
“Working on them, when I'm not repairing everything you break being reckless. I'll move them up my list though so we can implement them sooner if possible.”
Izuku was silent, but his big eyes were practically sparkling and Katsuki could almost hear it, Izuku's little voice: Kacchan, amazing!
Of course, he didn’t say anything like that now. Katsuki scolded himself for remembering.
Katsuki finally agreed to have Izuku start testing prototypes when he realized that Izuku showed no signs of leaving him alone as he worked anyway. It was… tense, to say the least, but Katsuki couldn’t really tell how much of it was just… him.
Some days were fine, but others… If either of them had a particularly bad day, all bets were off, and Katsuki kind of hated it. It was exhausting, like walking on eggshells, but Izuku wasn’t just- he wasn’t just some extra Katsuki could curse at when he was upset.
Unlike most of the people Katsuki had the misfortune of dealing with, Izuku… mattered, and that just made it that much worse that Katsuki was still so combative, so trip-wire sensitive, so damn aware of Izuku and their tangled up mess of a past.
Every time Izuku called him Katsuki-san, Katsuki winced a little, though he was getting better at hiding it. He still hated the days when Izuku showed up all closed off and short-tempered, his lips tight and pulled down at the corners, his gaze cold and fleeting.
For some reason, he preferred to be the one stifling his anger on bad days, but when Izuku looked at him like he was still the shit-faced, overpowered bully he’d grown up with while Izuku was all grown up, it made Katsuki’s skin crawl.
He wanted… He didn’t know what he wanted from Izuku, and it was frustrating as hell because none of it fit with Katsuki's plans, none of it made sense yet. All he knew he wanted was to be the fucking best at his job, to make sure Izuku was safe and able to be the best at his job. Some day, when he felt like he’d done enough, he wanted Izuku to be able to look at him with respect in his eyes. Respect he’d earned.
But Katsuki wasn’t there yet, he hadn’t done enough yet, and whenever he said Izuku’s name, he got this glare in return, like he’d lost even the right to refer to him.
But he had to ignore all that, because Izuku was around all the time now. He was around so often that Katsuki sometimes wondered when he had the time to bust up his gear bad enough to keep needing repairs in between prototype tests, when he even found the time to patrol.
Like today: Katsuki was at a point with the thrusters he’d been working on where he couldn’t go any further at the moment, so he didn’t have anything for Izuku to try out, and yet Izuku still dragged himself into the workshop after hours, his suit a little ragged but not in particularly bad shape, with the exception of…
“It's stuck,” Izuku explained sheepishly, rubbing the back of his neck. “The hinge cracked or something.”
“No shit,” Katsuki forced out.
The thigh supports were a newer addition to Deku's costume, solid bands of a sturdy nano-metal that connected down to his knee pads (like garters, Katsuki's mind supplied uselessly) and helped absorb and distribute the shock of his quirk more evenly across his muscles.
The one on his left leg was somehow, apparently, broken, and from the half-put together look of him, it looked like Izuku hadn’t noticed until he’d already been undressing and realized he was unable to take it off.
“Can, uh. Can you fix it?”
Katsuki fixed his eyes on the empty benches behind Izuku. “It’d be easier if it wasn’t on you.”
“Well, there’s not much I can do about that, Katsuki-san,” Izuku smart-assed back at him. “Unless you want me to actually tear it off, but I'd rather not.”
The confident reminder that Deku could simply tear through highly resistant nano-metal like it was little more than an inconvenient rubber band was… something.
Katsuki cleared his throat. “Yeah, whatever. Um. Come here, I guess. Closer.”
Izuku shuffled over, closer still when Katsuki shot him a glare. And then, from his rolling chair, Katsuki was suddenly face-to-face (or rather, face-to-dick) with Izuku's crotch. It was physically the closest they’d been since they were children, Katsuki thought absently, averting his eyes as best he could despite the inconvenient lack of space.
Unfortunately, Izuku’s thighs were beasts of their own, bulging with muscle that was visible even through the thick material of Deku’s costume, and the bunching of the fabric (and meat) around the thigh support was-
Katsuki would have called it mouth watering if he were the kind of person who cared about things like that, or if Izuku were… literally anyone else.
Still, Katsuki didn’t think about all that. It was just another piece of broken gear, and of course Izuku had to go and break it in the most inconvenient way possible. That was it. He didn’t focus on anything but that as he grabbed his smallest fucking screwdriver and a little laser and got to work.
“Stand- Fucking still,” he snapped the fifth time Izuku awkwardly shifted his weigh from one foot to another. “I have a laser cutter pointed at your flesh right now, if you don’t stop moving, I'm cutting you open, you hear me?”
“Yes, Katsuki-san,” Izuku responded tersely, and Katsuki scoffed at the tonal implication that Izuku could somehow be in a more uncomfortable spot than Katsuki right now, his head just centimeters from Izuku’s… belt.
It was delicate work, getting the support off without hurting Izuku or damaging the otherwise salvageable gear further, but Katsuki was nothing if not meticulous and damn good at his job, and before long, he finally had it.
“Don’t move,” he directed sternly as he pried his fingers under the support and began to wiggle it down Izuku's thigh, little by little. The thigh that he was absolutely not thinking about, except to curse the fact that Deku’s Shoot Style had built them so thick that they’d ended up in this situation in the first place.
No sooner than Katsuki got the broken gear off, Izuku was storming out of the workshop like there was a fire at his back, calling out an overly formal thanks over his shoulder.
Katsuki stared after him, annoyed and bewildered, the cracked metal ring sitting heavy in his hands. “Damn nerd,” he muttered to himself as he turned back to his bench to examine the support.
He ignored the shameful disappointment he felt in the pits of his stomach. Izuku hadn’t come to hang out, he’d come to have gear fixed. That was what Katsuki did for him. It wasn’t like they were friends or anything.