Bakugou and Denku are your parents (don't ask how) you were born during a snow storm so they brought you to U.A with them and they carry you in a basket lined with pillows and blankets over your head but you are crying because your still cold

Bakugou:Denku where's the extra blankets

Denku:right here (hands the blankets to bakugou)

Kiri:aww poor baby

Mineta:I have an extra blanket she can have

Momo:me too

Aizawa:I could probably look in the storage closet for extra blankets