Sloth. No, he's not a homunculi, and I'm not referring to him in the biblical sense. He possesses three hairs on his head, a Grinch styled demeanor (with matching grin), and a small doctorate from who knows where, which is why he is generally referred to as "Dr. Sloth", among other names. Basically your average all around pure evil mad scientist world conquering nut. He tried to fire some sort of laser at the planet we live on a while back that would have enslaved all the inhabitants under mutant mind control, then there was the whole desert war thing slightly more recently (if you consider "ancient" to be a term referring to something recent), and in general he likes to remind us that he exists only to lord over us with his robotic clones, the various mutant potions he's cooked up, and his self declared self proclaiming holiday of honor and destruction.
Oh, and to constantly terrorize us with the consequences of all his past actions. What comes to mind is the failed "Virtupets" experimental prototype, and of course the odd stuff we're dealing with now.
Dr. Sloth also introduced us to Grundos, who despite the fact appear in the Meridell defenders game, were supposedly not from our planet and were taken to be enslaved by Sloth from somewhere else. And then there's the Virtupets Space Station, which appears to be fully functioning save for his absence.
It is suspected that he is behind the long mysterious operation on Kreludor, even though nothing of any occurence has ever been found there, besides the soda machine of DOOM, and the lever of DOOM, both of which point in Dr. Sloth's direction. Almost literally, in the evil money snatching hand's case.
That's basically him in a Brazil nutshell.
Let's not forget the Ski Lodge Mystery either...
I rather wonder why the trapped staff never figured out who was behind it, what with his picture all over the walls...