Izuku is your brother and he 'died' 3 years before you

you are the new student at UA, and as you walk into the class of 1A your uncle Aizawa introduces you Aizawa: this is the new student, introduce yourselves as you look around you see a green haired boy with purple parts in his hair, he looks at you and smiles

Izuku: hey... sibling

Bakugo: your related to the nerd?!