Uhhhh oh...wow. Dude. Ansem is the final boss in KH. He's the villain. Granted, that's a later-stage reveal, since the notes you find indicate that he started out as a good guy...

Anyway, it's actually sort of okay, because re: Ansem, KH2 plays the "everything you know is wrong!" game.

I love Mickey. If you ever play Chain of Memories, he's actually an important supporting character in Riku's story mode.