I was watching the movie Heros Rising and while they were describing how Nine got his quirk it briefly shows "The Doctor". He explains to Nine that he has All for One's quirk, which means he can have nine quirks as well as his own. It's never explained how this works, so I was wondering if anyone caught onto it and look into it more. My only theory is that All for One is just like One for All, where it can be transferred, but that is immediately shut down because the movie has almost connected to the show itself. After all, it would affect the storyline too much. If someone could explain, it would be appreciated.