i- i had the assumption that deku in all for one's son, why cuz maybe all for one kept marrying women all over the world to take the children's powers, and that's why deku was powerless at first. also with the X-Ray in the beginning stating that his pinky has a joint if u look closely the doctor that was there was actually working for all for one if you read the manga you would know that.... sooooo maybe deku's power's was the purple thing that all for one has?!?!?! REEEEEE UWU