You're a villian and you've been captured by All might, because you're 15-16 they don't send you to a prison but to class 1-A so maybe they can change your mind and make you a hero.

Aizawa:"Come in"

Izuku:"I can't believe our new classmate is a villian.."

Uraraka:"We will be fine-"

Bakugo:"Yeah sure, you wish"

Iida:"Hey come on, don't be mean!"

Momo:"I'm sure we can change them.."

Todoroki:"We will see.."

Tsu:"Mhm" ribbit

Kirishima:"How bad can it be"

Jirou:"Good question"

Mina:"Mhm"