I guess my dumb brain just assumed that there would have been two separate realities like a future world where Aku was faded out of existence and everyone was fine and then the world jack went back to where he killed him
I have no idea what the intention of the ending of the show was supposed to be but I've always had mixed feelings about it either way
Considering that Ashi vanishes, my assumption is that the future where Aku ruled now no longer exists—after all, if Aku disappeared but all the impacts he made on the world remained in some split timeline, then wouldn't Ashi have remained, since she's one of his impacts?
So I sorta assume that everyone Jack ever knew in the future must've just, ceased to exist, because the circumstances that led to them even being born would've been so radically altered that their grandparents' grandparents' grandparents' grandparents never even met each other.
Which is a bittersweet ending—tragic, in a way—but if there are two potential futures, one that's "normal" and one that's defined by unceasing tyranny and destruction, and no matter what only one of these worlds will exist, and one of the worlds existing means everyone in the other world will never come to be, then which world would you choose to make exist?
I also feel like allowing for a split timeline where Aku did rule would be like Jack "failed." (After all, Aku still got his millennia-long reign of tyranny, but like it's not in Jack's backyard so it's fine, right?? I don't think Jack would accept that.) So I've always interpreted the show as a singular timeline that can be altered.
