I've been thinking about villains lately and the fact that my own bad guys (when they are human that is) tend to pretty much fall into the category of psychopaths. Not that they aren't complex, just that their emotions revolve around their own gratification and aggrandizement, with a self image that borders on the megalomaniac. I'm talking more about the top bad guys here, not the various spectrums of henchpeople.
I used to love the way David Gemmell would get into his villains heads. The way he used to present their thinking processes, and how they thought of themselves as sensible and reasonable, and how anyone would do what they had done in the same position - if they were as smart as they were.
Its interesting to note that a lot of the protagonists found in speculative fiction, thinking more toward the interstellar James Bond types characters, could also be considered as verging on psychopathic, or at least sociopathic. They launch nukes without a qualm, admiring the multi-faceted spectra of explosions while millions die. Feel no fear when challenged by twenty knife wielding assassins, confident in their own supreme abilities, and treat sexual encounters as fascinating meal breaks.
But all villains don't have to be lacking in normal emotional reactions. For true vindictive spite you need someone with intense emotion, combined with some really severe hangs ups - social isolation, emotional deprivation and an unrelenting drive to 'show them' mixed in with a good measure of entitlement. Hitler was supposed to be an emotional and intuitive type. He was also a non-smoking vegetarian (and a writer - if you count Mein Kampf).
So just to throw a few villains out there -- Darth Vader? Sauron? Dr Octavius? Psychopath or twisted fiend?
Split the head of your favorite fiend. What's inside?