I'm kinda glad we got Tar-Baphon in here.
My games never last long enough to get to the "legitimately able to kill him" level, but I like hearing about that dude, because his whole deal amuses me: in a world filled with giant monsters, slavering horrors from the Outer Dark, insane archwizards, a few outcast Demon Lords, ghostly god-kings, and lord knows what else, one of the biggest badasses around is a regular human being who really worked his butt off to become a wizard-tyrant and lich.