Whosaidthat got it.
Next Quiz.
This character expiraments with people a lot.
He is the first to be defeated in a certain group.
90 points.
Good Luck.
[Spoilers]
I think this is a trick question, after all the first person who could be fought from Organisation XIII was Xemnas (in the final mix version of KH1) and also the first person who could be beaten who liked to experiment with people was Xeonard's heartless in KH1.
[/Spoilers]