1. In KH2 we learn that the Ansem in KH1 was in fact the real Ansem's heartless and that Xemnas is the real Ansem's nobody. While DIZ was some kind of associate of the real Ansem. (This is the most simplistic plot) And in KH3 we fight Ansem as a whole being
This. It's actually on my list of "Ways KH Should Have Been Less Convoluted."
Even today, I still think relegating the Ansem from KH1 to the apprenticeship of the real Ansem in KH2 was a stupid move.
Basically, we were given two plot twists at once:
1. Ansem was not Ansem, he was his apprentice.
2. This apprentice was split into a Heartless and Nobody.
I remember the first time this information was presented to me, it took me a while to digest just who the fuck it was that I was fighting.
Now, why was the first plot twist necessary at all? It wasn't. Only made things that much more complex.
Still, I liked DiZ, and his desire for revenge, so I wouldn't want to throw him out. Maybe he could have been a co-ruler. Or, hell, maybe he was Xehanort's (I mean Ansem's) predecessor and the throne was stolen prematurely (without the name change and all that crap).
Despite the fact that I liked BbS, and even some of the implications it brought up about Xehanort and his subsequent incarnations, I also found that to be an unnecessary addition to what can now be called the flow chart of forms for our main antagonist.
Mixing Xehanort, Terra (and, hell, Eraqus) is just convoluted. Granted, it's not hard to grasp within the game's own plot (I mean, it's hardly any different than Xehanort's Heartless possessing Riku), but when you put it into context of the broader series (with all the other Xehanorts), it just becomes one more plot twist.
Honestly, I think it would have been better if Master Xehanort had simply warped Terra until he became evil on his own (though to what end, I won't dwell on since that would be venturing into fan fiction). That way we wouldn't have had that unholy mixture.
So, basically, the scenario, as I see it, would be:
- Terra is named Ansem
- Ansem grows evil as Master Xehanort's Apprentice
- Ansem winds up in Hollow Bastion after fighting Aqua and is taken in by AtW (who would not be named Ansem in order to avoid confusion).
- Over the course of the next decade, AtW, without a heir and impressed by Ansem (who he has essentially adopted), names Ansem as his successor.
- Ansem ends up taking the throne prematurely and banishing AtW.
- Ansem splits into Ansem SoD and Xemnas.
If that were the case, we'd only have three forms of the main villain- his whole being, his Heartless, and his Nobody.