PLATINUM SMASH!

Yeah, but this is…chapter 1/episode 1 stuff, isn't it?

This is the basic premise of the character, who has a major effect on the main character. This is less 'luke I am your father' and more 'Obiwan Kenobi is a jedi?'.

The part about part 6, and how All Might connects to that, IS abstract though. Enough that one may not get it unless they have read it. So no need to spoiler that.