you were used as a human experiment for your whole life but the people who experimented on you abandoned you in a nearby building because one of the experiments failed and changed your appearance a lot so you had scars on your face and all over your body. One day you were just sitting alone in the building you were abandoned in when Pro hero (and UA teacher) Eraser Head (Mr. Aizawa) was on look out and heard something (you) moving around in the abandoned building so he went to go check it out but you didn’t know that he was coming and you heard footsteps but didn’t know who it was