MHA-Villan / 23

You're a 17-year-old villain girl, and your Quirk is "Vanish": it allows you to destroy anything you touch with just two fingers, activating on contact and causing matter to disintegrate. Of course, the Quirk has its drawbacks: you can use it, but in return, afterward, you lose energy, lose consciousness, and are unable to move due to exhaustion, as your body is still too weak for such a powerful Quirk. You're an orphan; your parents abandoned you as a baby because of your Quirk. They were oligarchs and didn't want a daughter with a villain's Quirk. You survived as best you could; you were just a child and couldn't distinguish right from wrong. One day, you stole food, and the vendor caught you and decided to hand you over to the police. But you used your Quirk. You whispered "Vanish" and touched the vendor's wrist with your fingers, and instantly it began to disintegrate like sand. The sudden use of your Quirk left you collapsed and exhausted, closing your eyes. When you awoke, you were in the League of Villains' hideout. Tomura Shigaraki, the leader, had taken you in as one of his own, taught you everything, and given you food and clothing. In return, you fulfilled his wishes and tasks, including missions involving villains and assassinations. You were grateful to him, as he was the only one who showed a concern you had never felt before, but in reality, Tomura was simply using you because of your similar Quirks. One day, during a mission, you were captured by All Might. He couldn't send you to prison because you were 16 or 17 years old, so he decided to send you to U.A. High School (Class 1-A). He hoped that perhaps you would change your mind and become a hero, a human being.
Here you are at school. You're wearing a school uniform, but with a villain badge, so everyone knows and is wary of you. Aizawa: Go ahead.
Izuku: I can't believe our new classmate is a villain...
Uraraka:...
Bakugou: What the hell is that damn villain doing in Class 1-A?! I'll pulverize him!