Your his older sister. He'd only seen you when he was very little. 14 years later and you've come back to see your parents. You asked them if they locked your room, which was half gym and half normal room. They gave you the key and you entered. When Bakugo returned home, he realized that your room had been opened. Bakugo: "Who are you extra!?" he yelled at you furiously You were doing handstand pushups when he asked that.