Because it seems so rare for INTPs to villains I figured we might as well have a list for the few that are. Thanks to
ZPowers and Speed Gavroche from another forum.
Bill from Kill Bill:
Is reclusive and works in the shadows, has a lot of Ne especially when he is talking about superheros in Kill Bill: Part 2. Spends his time with intellectual pursuits like inventing a truth serum.
Roger "Verbal" Kint (Keyser Soze) from The Usual Suspects:
Is it still a spoiler if the film's been out for almost a decade (and basically defined by the spoiler)? At any rate, Kint aka Keyser Soze is a clear INTP when he gives the story to the detective. It's possible that, like his crippled leg, it was all just an act and he's actually an INTJ or whatever but from what we can tell he came off as very INTP.
Scarecrow from Dark Knight Batman series:
His only motivation is to understand fear and has no interest in money, power, revenge etc. Also his character has a lot of Ti like when Rachel remarks how it's convenient that his client is suddenly crazy and he responds with something like "well as you can see it's never convenient to have a mental breakdown."