I need an evil name. Can somebody help?

I'm writing a story, and I need a name for a character who is always lurking in the shadows, is conniving and creative, and ultimately controls everything that happens by pullins behind the scenes. He is all-powerful and very mysterious (nobody really knows if he actually exists or not) and is comparable to Lord Voldemort in the Harry Potter series in terms of ruthlessness. I was thinking something like 'Valentine' or 'Sir Valentine'.... something spooky, yet subtle, something to strike fear into the hearts of everybody who hears it. Anybody have any suggestions?