"when kingdom hearts is complete, it is said the one who opens its door will bring about the creation of the next world. Such a feat is above any human. Or, to put it another way: whoever opens that door will be reborn as something far greater than human." 

 

I understand why he wants kingdom hearts. I mean, it sounds pretty awesome. Also he believes that light and dark should exist in balance. Sometimes, i think the light tries too hard to snuff out the dark and think that they should co-exist, just like MX thinks. Maybe he doesn't go about it the right way but... i think he has a good overall idea.

Lets see he's possessed a person, made a being of darkness , sent unversed into multiple worlds, killed Eraqus, tried to kill Aqua, lied, because of him multiple worlds were lost to darkness, including the Land of Departure which he destroyed himself, Ven is in a coma because of him, he tried to make Sora a clone of his along with other people, he's put all worlds in danger multiple times! He's bad.