>>34532631His character did end there.
You can assume the Rainbow Rocket Giovanni comes from a universe where he did succeed in whatever TR was doing and has been amassing power from universe to universe. It's completely fucked and bonkers and from a writing standpoint is a weak crutch and the worst way to introduce rogue elements if you incorporate a multiverse into your world. Now the possibilities are endless making the player's past merits and demerits nearly pointless if they can both exists and not exist given the choice of accepting the reality or not.
Any theory or question can simply be written off as: "Well, even if it can't happen in the game/anime/manga it can happen in another universe because that's a thing."