User blog comment:27finnsprincess/First Footage of Season 5 :D/@comment-4238265-20121029233853/@comment-1784834-20121029235127

I think The Lich was originally a human, who was the dictator of the country the USA went to war with (probably Iran or North Korea, maybe China). He wishes to destroy all life because if his totalitarian government can't rule the whole world, no one can live to tell of his embarrassing failure to their grandchildren.

Another theory is that he is an alien who wants to destroy all life on Earth to make way for his own race to colonize the planet and eventually dominate the universe.