Most evil anime villains

My wife and I are going through and watching Inuyasha (her favorite anime), and I'm having a hard time thinking of a more evil villain than Naraku. Orochimaru from Naruto comes to mind, but I can't think of any other just complete bastards with no redeemable qualities that are worse assholes than them.

What are some of the most evil anime villains you can think of?

I don't watch too much anime. I do every so often. ...bah since I can't think of one I will just go with Dark Fact from the Ys anime even tho I'm sure he isn't. Just the only anime I really watched with a true villian. Most the stuff I watch is like GiTS,Cowbow Bebop,Morbito,Gurrenlagen and video game ones.