Aizawa knew your parents before they died. When he found out they died he was gonna start taking care of you but suddenly you had went missing

On TV he saw a hero fighting you, he rushed to the place and captured you. You sat at UA in his office, he walked in after he had a talk with the principal

"Listen kid, I know your past and that's the only reason I'm not putting you in the slammer. I'm allowing you to have a choice here, do you or do you not wanna enroll in UA?"