A/N:

Warning for swearing again. lots more than last time, now that he's not a literal baby and has more lines.

side note: im also posting a chapter either tomorrow or on thursday

initially, i wasn't going to write anything about Katsuki's stay at the Dursleys, but several people had asked about it, so I wrote a quick chapter I have to admit, I had no idea what he'd do so it's not my best work, but I hope it's alright :P

Katsuki woke up in an unrecognizable room that reeked of disinfectant, with a grimey feeling in his forehead, and having his vision filled with the sight of the face of a woman whose far-away gaze and pinched expression showed an absurd combination between grief and severe disgust.

Cakeface, he'd dubbed her almost immediately, because with how much makeup she slathered on her face, he wouldn't be surprised if her suffocating skin had rotted underneath.

It had only been after she'd left the room - leaving him entirely alone despite the fact that she'd have no idea of his true age - that his situation truly settled within his mind.

He knew, from little snippets of conversation and from catching glances of the Harry Potter books and movies, that after his parents died - don't think about it, don't think about it - he'd be forced to live with his extended family, and in conditions that would put them on the other end of Aizawa-sensei's scarf faster than they could say 'irrational.'

It made him wonder where his uncles had gone, though. Had they died? Gone into hiding? Simply left?

He couldn't blame them, whatever happened. He didn't want any of them to die, so even if he had to deal with a bunch of raging assholes, he'd be alright as long as they were safe.

(It didn't mean he didn't miss them, though.)

Anyways.

Aunt Cakeface, despite her faults - and mind you, she had a lot of them - was slightly more respectable than her husband. While Vernon Dursley - who he named Fuckwit because he was, in fact, a fuckwit - had no qualms with screaming at a literal baby for daring to have basic needs, Aunt Cakeface screwed her face up and actually dealt with things.

Not that he liked her, though. She was still a bitch - especially because, not only did she constantly complain about having to take care of him, she allowed her husband to force him to live in a cupboard.

A fucking cupboard.

The reason?

Uncle Fuckwit wanted their son to have a playroom.

(Needless to say, Katsuki did not like the Dursleys in the least.)

Marge Dursley was a Bitch with a capital 'B' and Dudley was a sore fucking loser.

Having not interacted with his cousin or uncle very much for his first years at the Dursleys, he'd managed - if just barely - not to blow up in any of their faces. He'd internally sworn at them, insulted them, and so on, of course, but miraculously, he managed to hold his tongue.

And then his bratty cousin's fifth birthday rolled around and things went to hell.

He was very unsubtly insulted throughout the day by Aunt Bitch and Uncle Fuckwit, which was incredibly annoying, but nothing he hadn't heard before. He could always curse them out later, when he was alone and not in danger of spending his entire night in a cupboard - something he tried to avoid, not because he was particularly scared by the concept, but because tight spaces and a lack of exits did, admittedly, make him uneasy.

Unfortunately, he'd overestimated how many brain cells were inside Aunt Bitch's apparently hollow skull, because when she noticed that Katsuki was winning the game of 'musical statues', she started wacking his shins with her goddamn cane so he'd lose.

He was barely able to catch himself before he fell flat on his face, and immediately spun around to point a glare in Aunt Bitch's direction. Disgustingly, she looked positively gleeful when she'd hit him, and then genuinely annoyed when he didn't get brained by the floor.

While he was trying to comprehend just how fucked up that was, he felt his hair prickle on the back of his neck, and a moment after stepping to the side, he watched Pigsty - who he'd aptly named over his messiness and tendency to eat like an animal, only barely deciding against 'Fuckwit Jr.' because of how young he was - fall over before immediately bursting into tears.

Before he knew it, the room was filled with the sounds of shouting, crying, and consoling all at once, and he felt a soft, buzzing sound grow in his ears.

And then.

"Oh, I feel so sorry for you two," Aunt Bitch said loudly, tossing a disgusted look in his direction. He barely paid attention, focused on a familiar burning within his chest. "Having to take in an urchin like him must have been hard, I imagine. Oh, not that it's your fault," she added, frowning up at the flickering lights. "Upbringing has nothing to do with it, in this case. It's a case of having been born to the wrong family. With parents like his, it's no wonder he turned out so poorly, unlike Dudley."

"You know nothing," Katsuki said, hearing blood rush past his ears. "You know absolutely nothing about them."

Aunt Bitch's face screwed up, and she rolled her eyes in the direction of everyone else. "See what I mean? A rotten egg, just like his pare-"

Warmth exploded within Katsuki's body, and one-by-one, the lights above them shattered, plunging the room into darkness and causing glass to rain from the ceiling.

Curses died on his tongue as screams sounded out, and he found himself jerking backwards in surprise.

Just like-

A man growled next to his ear, and he sucked in a sharp breath when he found himself being grabbed by the collar. "I knew you'd be trouble. I knew you'd turn out to be a freak," he ranted as Katsuki tried to free himself. "You're lucky we can't throw you out, or you'd have gone the moment you arrived." He slammed open the door under the stairs, which Katsuki could just barely make out in the dark. Then, he threw Katsuki to the ground before spitting at him. "You won't be leaving for the next week, boy."

The door slammed in his face, and moments later, its lock clicked in place.

Despite himself, the blonde shivered.

True to his word, Uncle Fuckwit hadn't let Katsuki out of the room for the next week. The occurrence was rarer than it used to be, though, and whenever he turned around, he felt suspicious gazes directed his way.

Not that Katsuki actually cared. People looking at him like a ticking time bomb wasn't anything particularly new, and although he was uncomfortable in the small cupboard, it wasn't debilitating after the first night.

Still, it did force him to put a rule in place: no magic. He couldn't control it, obviously, but whenever he felt buzzing underneath his skin, he knew to leave the room before anything could get out of hand - less because he was genuinely scared of the Dursleys, and more because he wasn't too keen on being a living ragdoll. As much as it annoyed him, everyone in the house was physically stronger than him, and somehow, he doubted that Uncle Fuckwit would restrain himself from flinging Katsuki across the room if he displayed magic once again.

The only exception to this little rule was the 'metamorphmagus' thing, which he'd practiced during his week of solitude. Without a mirror, he couldn't do anything especially interesting, but he'd been able to figure out changing his hair color and length easily enough, and while he avoided it because bone growth and shrinkage was fucking painful, he knew that he could adjust his height at least a few centimeters in either direction.

Otherwise, though, no magic. Not until he got his hands on some magic-related books, at least.

There was one, one genuinely redeeming feature about the Dursleys, and it was similarly limited to one of them. Newsflash: it had nothing to do with Uncle Fuckwit or his demon spawn.

When Katsuki had turned five a month after Pigsty, Aunt Cakeface had actually given him a present. Not one that she'd bought, but the picture book he'd gotten from Peter for his first birthday. He wasn't sure where or how the hell she got it, but he did know that she probably didn't know exactly what it was, because otherwise, she wouldn't have given it to him (considering the fact that the pictures were enchanted to move, and all).

As a plus, she looked sour while handing it over to him - discreetly, because there was no way Uncle Fuckwit or Pigsty would stand for him getting any sort of present - but just for her, he didn't mentally insult her for a whole hour. A real record, he'd say.

Obviously, the book was buried under his thin-as-fuck pillow and only pulled out when everyone except him had left the house or they were all asleep because he wasn't about to let it get stolen by Pigsty for his toy hoard, or just ripped up to mess with him.

Still.

It was appreciated, and Katsuki would be lying if he said he didn't spend the night leafing through the book, watching as his parents and uncles waved back at him.

"Fuck off, dickwad," Katsuki said simply, causing a few sets of eyes to widen around him.

Pigsty, who took a few moments to register that what he heard was probably offensive, sneered. "I told you to move."

"And I told you to, and I quote, 'Fuck off, dickwad,'" Katsuki repeated, expression remaining purposefully blank.

The boy, who Katsuki knew had barely ever been told no in his life, stepped forwards, punching his fist into his other hand in a way he must have thought was menacing.

It was not.

"Move before I make you," the boy threatened, and as gasps rang out, he couldn't help but notice how cliche this all was.

His eyes flicked behind him, noting that the boy behind him had pushed himself to his knees and was looking at Pigsty warily.

Katsuki turned back towards the heavier boy and raised a brow, causing his expression to twist even further.

"You asked for it, freak," he spat out, charging towards the technically-younger blonde.

He briefly looked towards the sky.

Was this his punishment for being an asshole before? Was Deku laughing at him, wherever he was?

Probably, he decided, and caught Pigsty's fist in his hand. Pathetically, it did sting a little, but not because of any faults of his own. Anyone would be pretty damn weak if they were fed the bare minimum every day.

"For your information, since you attacked first, this is self-defence," he said, and as the boy's expression morphed into one of confusion, he grabbed Pigsty by the wrist and kicked him in the gut. It wasn't particularly powerful or the best option for the situation, but it wasn't like he was going to go full-out on a literal child. Still, it did cause him to stumble backwards and fall to the ground.

"Fuck with anyone again and it'll hurt more," he said, narrowing his eyes. The brat looked shaken, but still defiant. Despite Katsuki's image, he didn't actually like seeing people upset, but it was clear that the brat needed a lesson to be drilled in and he wasn't about to start pummeling him into the ground.

So, after meeting Pigsty's gaze, he made his eyes flicker red - something he'd taught himself a few weeks prior - and Pigsty paled, letting out small hiccups. Seconds later, the hiccups turned to cries, and then into full-blown wailing when the surprised snickering started.

After watching the boy run away, Katsuki turned around to address the bruised boy who was now looking up at him with something akin to awe.

Nope, he mentally told himself. Nope, nope, nope. Not again.

"Bye," he said, then immediately walked away. The kid startled and called out for him after a moment, but it only caused Katsuki to quicken his pace. He didn't need another fanboy. He didn't need another reminder.

Pencil scratches echoed within the kitchen as Uncle Fuckwit went through the daily crossword, only for the noise to pause abruptly.

"What's a cage for a rabbit called?" he asked gruffly after a few moments.
When Aunt Cakeface gave an unsure frown and Uncle Fuckwit started looking impatient, Katsuki answered. "A hutch."
Uncle Fuckwit pursed his lips, but noted the answer. "Right," he grumbled, and continued.

Several minutes later, he spoke up again.

"What's a 'double-reed wind instrument?'"

"Oboe."

Uncle Fuckwit narrowed his eyes. "Seven letters."

"Bassoon."
The man glanced over the paper and wrote it down.

"And… what is 'the smell of the earth after rain?'" he asked, looking almost insulted by the question.

"Petrichor."
Aunt Cakeface looked at him incredulously, but didn't speak up.

Uncle Fuckwit went through several more answers before stopping once more. "What's a six-letter word for 'disappointment?'"

Katsuki hummed. "Vernon."

The man took his pencil to the paper, only to freeze. His gaze lifted, and Katsuki's lips curled into a smirk.

"Cupboard," Uncle Fuckwit ground out, face looking about as red as a tomato.

"Worth it."

Dudley didn't end up telling anyone - either his parents or a teacher - about being kicked by Katsuki, which he strongly suspected was because he didn't want anyone else to know he'd been embarrassed.

What he did do, however, was turn all of his bullying efforts towards Katsuki - even more so because Katsuki's grades were far better than his cousin's. Homework destroying, pencil stealing, blaming, and other childish tactics were all used in an attempt to make him miserable.

Since he wasn't an actual kindergartener, though, he didn't care in the least, which somehow boosted his hero image - which had started because he'd 'saved' the other boy (who was in the year below him, apparently) from Pigsty. It was annoying, but not as bad as it could be since they were all still children, so he let it slide.

This, however, ended up making Pigsty - and his lackeys, who Katsuki didn't learn the names of, and only bothered to give one of them a nickname because looking like a rat and being named Peter had registered as an odd enough coincidence in his mind to do so - even angrier, and ended up confronting him.

News flash: this did not work out well for him the first, second, or third time it happened.

Eventually, instead of telling on Katsuki like he thought he would, he ended up coming up with the brilliant idea of beating up other children to get him to 'submit' some time after they'd turned nine.

Upon finding this out - because it wasn't like it was even supposed to be a secret - Katsuki had promptly seeked out the brat, who seemed far too smug for someone who had such a stupid fucking plan.

"If you don't do what I say, I'll keep beating them up," Pigsty announced with a grin.

Katsuki blinked, wondering if he needed his ears cleaned out or if his cousin genuinely had a brain cell deficiency. Then he remembered who his parents were, and easily settled on the second option.

"How about a third option?" Katsuki asked, already cringing about the middle-school bully act he was about to put on. "Where I pummel you enough that you can't lay another finger on anyone ever again?"

Pigsty's eyes widened. "Y-you can't do that. You'd get in trouble." Katsuki allowed a grin to spread across his face, and the boy paled. "You can't," he repeated, eyes flicking back to his lackeys who seemed unsure of what to do.

Oh, what Katsuki wouldn't do for some handheld explosions. Unfortunately, he wouldn't be able to look into recreating his quirk until he made it to the school with the weird-ass name, so all he could do for now was use what was, at the moment, his glorified party trick.

He felt his face morph into something that was incredibly similar to before, but just off enough to look unsettling. His eyes flickered red when they caught the light, and as he stalked forwards, his height grew near-imperceptibly. "Can't I?" he asked, hiding his slight embarrassment at acting like a pathetic anime villain with an eerie grin.

Pigsty trembled, and as soon as the tears began to fall, Katsuki hardened his gaze and dropped his grin. "I've already told you to fuck off, Dudley. In case you didn't notice, I don't care about getting 'in trouble' as much as you'd like to think. And for your information, threatening others isn't going to do anything except piss me off." He jerked back suddenly enough to startle the brat, and he returned his features to normal. "If you want to be liked, maybe try being a better fucking person instead of using these shitty intimidation tactics for once. They'll only get you so far."

Pigsty looked slightly chastised, but Katsuki knew he didn't understand. He couldn't - not for a while, at least. Still, he also knew that he wouldn't try something so utterly moronic again, and after another moment, he left.

He'd never been able to abate the Dursleys' hatred of him. Not that he had tried especially hard, but there was some effort.

Unfortunately, all attempts seemed to backfire on them. They'd either be suspicious, figure that he was 'showing off,' or just generally disregarded anything he did.

For example-

He got good grades? He was showing up 'poor wittle Dudley!'

He got bad grades (which he only tried once)? He was an ungrateful brat who wanted them to look like they didn't teach their children. Katsuki was quick to point out that they didn't, but considering the fact that he got shoved into a cupboard for the rest of the night afterwards, he doubted they liked that response.

-and other such juxtapositions.

Anyways.

Whatever he did would get him sent to the cupboard without dinner, slapped, extra chores, or whatever the fuck the sadistic assholes felt like making him do.

And he couldn't do a thing about it.

He protested, obviously, but it wasn't like that helped. Eventually, he'd even tried to get the hell out of dodge more than once by unlocking the cupboard with one of Aunt Cakeface's hair pins and running away in the middle of the night, but somehow, he found himself back in the house every single time.

So basically, all he gained for his efforts were more locks and an extreme hatred for whoever decided that putting him with the Dursleys was a good idea.

More than all other days, though, Katsuki really wanted to commit homicide on Pigsty's eleventh birthday.

"Thirty six?!" his cousin shouted, going red in the face. "But last year I had thirty-seven!"

Katsuki knew, realistically, that he was a pretty shitty child. However, that was more his classmates' and teachers' ego-boosting than anything having to do with his parents. They never spoiled him unless he actually deserved it, and when they felt he was getting too demanding, they were quick to put him in his place.

The Dursleys, though, encouraged the brat's behavior. Uncle Fuckwit actually looked proud half of the time when he was throwing a tantrum - and wow, he really just ruffled the brat's hair and praised him, didn't he? - and instead of teaching him a single thing with a punishment or even a talking to, Aunt Cakeface always quelled his rage with promises of more new things. It was why, even after managing to get him to be less of an ass towards him, he was otherwise still a brat.

He withheld a sigh. Whatever, he thought. At least I won't have to deal with this all day.

"Bad news, Vernon," Aunt Cakeface suddenly said, jerking her head in Katsuki's direction. "Mrs. Figg's broken her leg. She can't take him."

…

Ah, fuck.

Katsuki didn't particularly like Mrs. Figg - there was something about her that was off and, considering the buzzing feeling he entered certain areas in her house, he was pretty sure that something about her was magical, which he wasn't quite sure how to feel about - but other than staying with Aunt Bitch - who, he was pleased to note, was separated from him nearly every time she visited, after the light-bursting incident - he'd rather do just about anything else than spend the day with three spoiled assholes for an entire day. He'd gotten used to them, yes, but at least at their house he could stay away from them for the majority of the day. In a public space, however…

"Now what?" Aunt Cakeface asked, glaring at Katsuki, because apparently it was his fault the woman was injured.

"We could-" Uncle Fuckwit paused suddenly, looking at Katsuki with large, pursed lips when his head snapped in the man's direction. The man was going to suggest making him stay with Aunt Bitch, he just knew it. "...What about whats-her-name? Your friend… Yvonne?"

The woman's expression became sour. "On vacation in Majorca."

Katsuki briefly considered asking if he could just stay at the house, but there was no way they'd agree to that. He'd lost the meager amount of trust he had when he'd accidentally displayed magic for the first time.

"I suppose we could take him to the zoo," Aunt Cakeface said slowly, "…and leave him in the car…"

...What the fuck?

"That car's new, he's not sitting in it alone…"

Again.

What the fuck?

He glanced to the side to seeing Pigsty looking miffed, but not enough to protest the circumstances. He didn't like Katsuki, but he didn't exactly hate him anymore, either, leaving them on shakily neutral terms.

After another minute or two of tuning out his Aunt and Uncle's asshole-ish conversation, the doorbell rang, and in came Rat-face - otherwise known as 'Peter Polkiss' - and half an hour later, they were all on the way to the zoo, which they reached after Katsuki had endured another thirty minutes or so of constant complaints.

The trip, to his surprise, was actually pretty decent for a while. He'd been to zoos before, but that had been a long while ago, and the trip gave him an excuse to be far away enough from the group that he didn't have to listen to them whine. He did want to pummel in the two boys' faces for fucking with the animals, yes, but he managed to restrain himself and simply got them the hell away each time they started looking annoyed or upset.

And then, of course, everything went batshit crazy.

(Okay, that was an exaggeration, but god damn, could he not have a single peaceful day in his life?)

After Pigsty left the reptile exhibit because they weren't moving, Katsuki was left sharing an exasperated look with a boa constrictor.

Who promptly winked at him.

Or he thought it was a wink. Without eyelids, it was hard to tell.

His chest rumbled, and a hiss escaped his lips. "The fuck?" he asked in what was probably snake language.

...Goddamn wizards.

The snake looked to be a mixture of confused and curious.

"...You like it here?" he asked after a moment, accepting his fate.

The snake shook its head rapidly.

He glanced at his cousin, who was still hellbent on terrorizing the animals. "Fair enough." He hummed, glancing down at the boa constrictor's placard. "So, your name is… Boiúna?"

As the snake nodded, a shout came from behind him, causing Katsuki's fists to fly upwards. Rat-face gave him an odd look, and just then, Pigsty arrived.

"Woah," he let out, pressing his face against the glass. "Is a snake supposed to do that?" The snake lowered, looking disinterested, and Pigsty's expression turned from awestruck to sour. "Hey, don't stop! Come on!"

"Harry was doing something!" Rat-face announced, and Katsuki took in a breath at the name, not having been used to it after barely hearing it a handful of times for the past few years. "He was talking to it - weren't you?!"

Both Rat-face and Pigsty turned their gazes towards him and he forced his expression to become blank. "No."

Pigsty leaned forwards. "I bet you were! Do it again!"

"No," Katsuki repeated, glaring at the two.

Unfortunately, Pigsty seemed to have been lost in his excitement, and pushed Katsuki. As soon as he felt the warm, buzzing sensation bubbling within him, he moved to stand, but Rat-face grabbed his arm and leaned towards the exhibit. "Don't be- wOAH!"

"Oh fuck," Katsuki let out, watching as the two brats fell into the now glassless boa constrictor exhibit.

"Brazil, here I come… Thanksss, amigo," the snake hissed as he slithered past, and Katsuki understood him because of course he did.

Katsuki pressed his hand against his face and inhaled. He already knew he wouldn't see daylight for the next few weeks.

Despite being locked in a cabinet for a good chunk of time, the weeks after the 'boa constrictor incident' weren't actually terrible. Pigsty's friends were nuisances, sure, but aside from making enough noise that he wouldn't be surprised if a noise complaint came in, they weren't awful.

And then July rolled around, and he got a letter.

A Hogwarts letter.

Fucking finally, he thought, glancing over the green-inked envelope. Then, before Uncle Fuckwit could start shouting, he slid the envelope under his door - because there was no goddamn way he was letting his magic-hating relatives so much as see such a thing - and handed everything else to the man.

An hour or so later, he was 'allowed' to return to his cupboard, and he read through the letter. It opened with a standard introduction, briefly mentioned Hogwarts, listed out a school supply list, and ended with an expectation for a reply.

...Which, he realized, might be a problem, because he had no goddamn idea how to contact them. He very vaguely remembered something about owls that might've carried letters, but he didn't have an owl, so it wasn't like that'd help him at all. And, somehow, he doubted that either his Aunt or Uncle would help him out in this scenario.

He let out an annoyed breath and pulled out a paper and pen before opening up to a new page and beginning to write out a reply. He figured he could at least do that much until he could actually send the damn-

Wait.

If he was right and Mrs. Figg was at least somewhat magical, she'd probably have a way to contact wizards. Even if she didn't particularly like Katsuki, he could still always ask...

...And since Pigsty's friends were coming over later, he'd have an excuse to visit the old woman.

He grinned, finishing up his reply.

Check and mate, Dursleys.

A/N:

aaahhh like i said, awkward chapter, very unfun

but just an fyi (because I wasn't going to shove every instance of Katsuki doing everything in here):

Katsuki is more subdued here - not because he *wants* to be, but because he *knows* he's outmatched as much as he wishes he could punch the Dursleys' faces in...

1.) He's a malnourished child. Vernon could throw him across the room without effort, and he can't even attempt to exercise properly or else he'd be burning too many calories.

2.) He was combat trained, but he's not used to fighting in this new body. He'll still be good, but he'll have to relearn everything. At most right now, he could take down an older child - not an adult, and *especially* not an adult as large as Vernon (not like it'd really help anything).

3.) Added because of a comment. He's not using magic on purpose. He doesn't want to kill himself or someone else by using something he's not trained in. He's impulsive, not stupid.

So instead, he's petty, because what else can he really do?

and as for his and Dudley's relationship: He doesn't like Dudley, but he doesn't hate him either. He recognizes that he's a child with a bad upbringing, and he really doesn't know any better. He'll think differently as Dudley gets older - because by then his choices will be his own - but as of right now, he sees Dudley as a kid who got messed up by his parents. And, after the several incidents, he and Dudley have come to a sort of truce-based understanding. They don't like each other, but they can tolerate each other.

anyways

Thanks for reading!