I think he's pretty cool. If I remember, you don't see him much throughout the game, but his presence is felt because an empire has to have an emperor.

Spoiler warning, I guess!
I liked how he was such a wimp when you fight him the first time, and he dies like it was nothing. Then he breaks out of Hell! And brings some demons along with him! That's... one of the most hardcore things a villain can do.