You can retroactively insert yourself in anything or anyone's story. If you wanted, everyone would think that you are the Hebert's youngest child. Or maybe you were always the president, even though you are clearly a minor. Cauldron? Of course you know about them, you were there in their founding. Want to be a movie star? You are, you just started that movie, did you not? Can I get an autograph? Whatever new “truth” you decide, the world will change to accept it: paper trail will be created for your convenience, statues for your glory, even the crater you made when you totally-one-shot a endbringer. This affect everyone in the world. You can dismiss any narrative whenever you want, and no one will notice you leaving. PS: Just because everyone believe you did something doesn't mean you actually did. So when you convince the world that you killed Scion, do try to act surprised when he show up to save a kitten or something.