The orphanage that you lived in forced you to be a girl when you were a boy. Your whole life you were so confused but once you get adopted into the yaoyorozu they found out you were a male but let you be who you wanted to,since you were more feminine and didn't want to be bullied you dressed as a female. You were dating a man named Cooper he seemed to be quirkless when he isn't. You all get into UA and that's when it goes down.