You're a transfer student from a prison program, the idea is to have you hang out around hero students your age so you get influenced by them and you act better. You get to wear clothes you like and you have your own dorm that you decorated.

When you get brought into the class you're wearing clothes you picked and your handcuffs have been removed.

Mr. Aizawa: "Class, listen up, we have a new student joining us, you may have heard about the prison transfer program."

Bakugo: "What!? You're having us take our class with some villain?!"

Midoriya: "Kachan, hold it, this may be a good thing."

Others in the class have their own comments as well, but that's right when you walk in and everyone looks at you