Two Explosions Are Better Than One

Izuku's original quirk is called singular perfect copy. It allows him to copy ONE quirk and he'll have it permanently. How does it work? I'm glad you asked. The quirk decides that the person closest to Izuku, that isn't blood-related, will be the quirk it would copy but also alter a bit. The problem was it would take the two people longer to develop the quirk... like 5 years longer. So both Izuku and Katsuki didn't develop their quirk until the age of 9. It still kept its strength as though they did have the quirk, they just won't be used to it. Izuku and Katsuki were considered quirkless for a short period of time but no one messed with them. Who would be ballsy enough to bully two short-tempered "Quirkless" children who at the time didn't have anything to lose. They could beat them senseless and claim self-defence or play the innocent card and when they developed their quirk it was bad. Two explosions sounded off, none of them being a small explosion. One green and one normal looking explosion.