I think the who's eyes change at the end, the one they call ES I think, is xehanort!
His hairstyle is the same the middle slicked back with the sides shaggy, the face even resembles a very young Xehanort. He probably was effected by the sight of kingdom hearts in someway that made him lose his memories so he spent years wandering till he ends up at radiant garden( I know thats a little vague...) THen he starts tinkering with hearts and all that stuff we know about to recover these lost memories. THis makes me think was Xemnas really doing anything bad, kiling heartless is good and the hearts have to go somewhere. Plus everyone who lost their heart could get it again now (yay!....) Heartless Xehanort or "Ansem" now he's bad cause, well, he's a heartless and darkness is all they know.
This leads me to the next part, the why. Wemnas wanted to remember this bald guy to get revenge. He was a keyblader warrior, a hero and he needs to get that back. He's the one who can stop him but without a heart he cant remember or summon a keyblade.
Maybe the bald guy and the knights were chasers and the bald guy turned on them using the keyblade for evil, like the two legends say. I also think the bald guys clothes resemble Heartless Ansem cause subconcsiously he it modeled itself after the most evil person that was locked in its memories.
All I know is I'm starting to think nobodies weren't bad as bad as people thought...
Hey man, could you make me a sig with Xigbar(KHII) and have it say, "Do I scare you...Is it my Scar?" That'd be sweet if ya could, thanks. Oh and leave the code with it.