I'm gonna say Kefka, because he's got that neat little pyramid thing that surrounds him, protecting him harmful UV rays and a pair of Gem Box'd Ultimas.

Honestly, Kefka was cool and all, but the folks at Squaresoft forget to include elemental crystals in his game. I mean, he could've been collecting them for their power or something. Or maybe they'd shatter when you show up, just in time to unlock the mysteries of the Blue Mage Job Class. Or maybe their power has faded thanks to Kefka's weird 2000 year immortality time loop thing, causing the world to rot away. And talking bats. And replace "crystal" with "orb". And replace "Kefka" with "Garland". And replace "send to the void" with "knock you all down".

FF6 was very crystal lacking. Unless you count Magicite. Which I don't. It's just dead animals.

Come on, even Mystic Quest managed to include something about crystals in the plot. Hell, that one guy who looks like a floating tree even turns out to be a crystal, in the end.

kinda like Sephiroth
Dang it. I am sooooooo tempted to respond to this about what I take to be Sephiroth's true nature and his intentions. But this isn't the thread for that.