You're All Might's child. When you were 11, the LOV kidnapped you and gave him a choice: you, or a town... he chose the town, and left. Thinking you were dead. But the LOV didn't kill you, instead, they took you in and trained you with your new found hate towards your father.

now you're 17 and a proper member of the LOV, the public just doesn't know it yet. You're walking around the city in the evening, smoking a cigarette, when All Might spots you from a distance while he's on patrol