Private settings are very important. It's probably the story of Izuku from the child generation and Uncle Ou from the parent generation swapping. Izuku with his own memories took the lead in becoming the eighth generation OFA, defeated AFO, and then faced the story of the newly born child generation (Uncle Ou has no memory).
Izuku had memories and knew about Todoroki's childhood tragedy, so he would intentionally get close to Todoroki when he was very young - the emotional story that evolved from this... And so on.