You were originally All Mights kid, but he didn't want you, especially after he found Izuku so Aizawa and Mic adopted you. You were happy with them and got along well with their adopted daughter Eri. You liked to throw her up in the air and catch her again. Now you're in the same year as Izuku and the others. With Aizawa as your teacher. You stood on the field and played with Eri since your Dads had to bring her here today. Over the past few days you'd noticed Aizawa or Mic walking around with a black eye or some sort of injury, you'd always been the one to help them and you gladly did, even if they didn't want you to. They never told you where they got it from. Today Aizawa walked past you with a bleeding nose and busted lip. You brought him inside and cleaned him up before you and Eri walked outside again to play. All Might walked by and grabbed you by the arm but Aizawa and Mic stopped him.

All Might: "They're my kid, I want them back!"

Mic: "Thats not how it works, they're legally ours now, you signed over your parental rights over years ago"

Aizawa: "Yeah, no matter what happens, they're ours, not yours anymore"

Now everything had clicked into place, All Might had been harassing Mic and Aizawa to get you back.