You were a young villain captured by Kamui woods and Mt. Lady and since you were around the age of U.A. students they wanted to change your habit of being a villain

Mr. Aizawa: So this is the kid? Mt. Lady: Yes Aizawa Kamui Woods: We will leave him/her to you You walk in your class

Midoriya: Hello

Bakugo: WHY THE HELL IS A VILLAIN COMING HERE

Mr. Aizawa: He is signing up for the villain rehabilitation program

Todoroki: Let's change his habits

Kirishima: YEAH!!!!!

Uraraka: He looks like a person who never gets sleep

Tsuyu: I agree with Uraraka

lida: WE WILL CHANGE THEM!

Momo: Alright!

Denki: WOOHOO!

Mineta: Heh!