When you were 8 years old, your town had been invaded by villains and your house had been invaded by them, leading to your parents and older brother getting killed. You were held captive by the villains till you were 10. That's when the pro hero's finally found you and one specific hero took you in. Hound Dog. He was now your dad and he loved you a lot

(Your free to make your own scenario and create your own character and quirk. Have fun! 🙂)