His first week is pretty average. He's hyper aware of every little thing he touches and glares daggers at every classmate that dares to giggle or point when he takes out a wet wipe to wipe any and everything down. He's doing this for their safety goddammit.
He learns his way to his classes. He catches up to the curriculum with ease, he makes a habit of eating in the library and avoids making friends like the plague.
That doesn't stop Kirishima from turning around every first period and beaming at him with that stupid face and asking him questions he never answers.
Bakugo hates liars, but that's what he is now. His parents ask: Make any friends at school? He answers: Yeah, tons. His parents ask: What is it you're doing at school so late? He answers: Joined some clubs for my college transcript. His parents ask: What are you doing this weekend? He answers: Going to the mall with some guys from class.
He does actually go to the mall but it's not intentional. He'd been standing on someone's fire escape looking out over a nearby park in full hero get up when he'd seen some punk snatch a purse. He jumped the railing and used his explosions to propel him in pursuit of the purse snatcher. The guy runs out of the park at top speed with Bakugo at his heels yelling curses and expletives that have mothers covering their children's ears and makes a mad dash into the crowd of the outdoor mall one block over.
The fucker must think he's lost him because he slows his pace to a casual stroll until Bakugo is grabbing the front of his shirt and lifting him off the ground while steam rolls out his nostrils in exaggerated puffs. And suddenly the little purse snatcher isn't so little. He's grown two stories tall, his head peaks out of the mall sky light and while Bakugo looks up from where he's sprawled out on the ground muttering a fuck, the guy bends down and grabs him in one hand like a deranged King Kong.
The mall transforms into pure chaos. People scream. He watches from twenty feet up as a girl trips and nearly gets trampled from the crowd. Fuck, he really fucked up.
"Hey! Fuck face! Put me down now and nobody has to get hurt!"
The guy laughs as he raises his fist above his head and lets Bakugo drop. There's a moment in midair where he almost panics trying to right himself, almost thinks he's going to die. The explosion is expertly timed though. He flies up while the guy is distracted looking for an escape.
He hides behind a pillar on the second story balcony and watches to make sure all bystanders are out of the way before aiming an explosion at the back of a knee and another at a walkway over the guy's head as he kneels. The bridge collapses as planned incapacitating the purse snatcher and Bakugo looks up to see a dozen or so people jaw dropped with their cellphone cameras facing him.
It takes a while to navigate back to the safety of his civilian clothes amidst the police sirens and nervous chatter of the hundreds of pedestrians that flood the scene to witness the damage. He somehow manages to get home unscathed and the second he opens the front door he's pulled into the tightest hug his mom has ever given.
"Katsuki! I'm so glad you're okay!"
"Yeah, mom, I'm fine. I wasn't even there." He lies again and he hates himself a little more.
Kirishima knows his friends are tired of him replaying the same video again and again and talking about how cool the mall vigilante is.
"I actually saw him-,"
"On your way to school helping some girls last week. Yeah, yeah, we've heard it a dozen times, Kiri!"
"Yeah, dude. He's not that cool. He put a lot of innocent people in real danger."
"He should have let the cops do their jobs, it's what they're here for."
"But guys," He whines, "Haven't you ever wanted to be a super hero?"
There's a snort, "Yeah, when I was, like, five."
He spends the rest of the day pouting and hardly saying a word. He stares out the window of his classes listless, dreaming of a day when he can wear a mask, a day when his skin is unbreakable.
He's dreaming up superhero names in last period when Kaminari breaks his train of thought.
"God, that new kid is so weird. Why does he do that?"
He looks up to see Bakugo meticulously wiping down his desk and chair.
"It's not even like he's wiping off other people's germs!" Ashido chimes in twirling a strand of pink hair between her fingers as she leans in to whisper. "It's the end of the day! He's leaving! Is he, like, sick or something?"
"I guess it is kind of weird." Kirishima acknowledges.
"Right!?" Kaminari buzzes excitedly.
"We shouldn't judge him though. Maybe he's just being thoughtful?" He offers.
"God, Kiri, you're no fun sometimes." The trio makes their way out to the courtyard slowly with bags slung over shoulders.
"Are you coming with us to Sero's?"
"I can't today. Sorry, guys." Kaminari stops dead in his tracks to stare him down.
"Man, what's up with you lately? You haven't hung out with us all week."
"I'm not doing so hot in Algebra." He says to his feet. "I need to go home and study so my dad doesn't freak."
Ashido puts a hand on his shoulder. "When have you ever been good at math, Kiri? I'm sure your parents will understand."
Kirishima laughs halfheartedly and scratches the back of his head. "Not this year. I'll catch up with you guys soon! I promise!"
"If you say so!" Ashido sings as they part ways.
He walks back to his empty house with his eyes on his shoes and leans heavily against the door as he closes it behind him with a sigh.
"What is wrong with me?" No one answers.
He sits at his desk, lays in his bed, and stands in the middle of the floor with blinds shut tight, doing the one thing he knows he shouldn't. He hardens his skin, and release, and harder, and harder until his skin feels raw and sensitive after long periods of being jagged and thick and when he looks in the mirror with his skin as hard as a rock he doesn't look like Kirishima anymore. He takes breaks to walk around the house dumbbell in hand, pausing to do squats here and sit-ups there and if his parents notice that he's been eating more they don't say anything.
AN: Sorry, first couple chapters are gonna be kinda short but once it picks up (and I have some more free time) expect much longer chapters.