Going to a detention center wasn't bad at first. Sure, he didn't enjoy it, but it wasn't as horrible as it could've been. The fellow delinquents there recognized him immediately and many feared him because of what he was capable of.
Being feared wasn't so bad. People at school feared him anyways. No, the worst part was the kids who weren't afraid of him. The boys who looked at Katsuki and saw nothing but an annoying boy who shouted too much and had a quirk to match his pissy attitude were the ones he'd learned to stay the hell away from.
A boy no bigger than him and only a few years older than him had quickly become his biggest issue. With red roots showing through hair that had been dyed black months ago and scars littering his body, a boy who went by the name Dabi was the reason he hardly slept.
He was forced to sleep in a room of four boys, Dabi included. The two other boys were a boy with black hair and a smile that came off as sincere but eyes that told lies, and a boy with a quirk that reminded Katsuki of a shitty zombie movie. None of them got along, but at least the other two had the decency to stay the hell away from him.
Dabi, on the other hand, never left the boy alone. When the lights went out for the night, Katsuki often found himself pinned beneath the other boy, being dared to make any noise to alert anyone who would listen.
The first night it happened, the boy had whispered words that Katsuki would never forget into his ear.
"This will teach you to pick on my little brother again."
Every night after Dabi was done with him, he would lie awake, face pushed into his pillow and his sleep pants tugged down to his knees. More often than he cared to say, blood stained his sheets, and he found it hard to walk for days on end.
The day Katsuki was released, he had done something he hadn't done in years. Crying out for his mother, he ran to her, throwing his arms around her and burying his face into her neck. Even when a particularly hard smack battered against the back of his head, he cried out, sobs ringing out and tears wetting his face.