If people are calling dibs on villain archetypes for characters they may or not make, I want to call the 'used to be a good guy but due to a belief that the ends were more important than the means he now must be put down by the very people he was trying to protect' type of villain. I can't help it, villains that you can't help but feel sympathy for when they're finally defeated are one of the most interesting kinds of characters in my opinion.
That's 'tragic villain'. For future reference.