What must the most pivotal part about your villain be?
You have to agree with them.
Such sordid and coarse words for an innocent little cripple (who wants to start a revolution) but it is the truth. Amidst the murder, gun firing, twisted philosophy has to lie a part of the antagonist you relate to. A part you see yourself in. A part, as my friend Richard O'Sullivan stated, that "Justifies their actions to themselves."
I had this experience writing Breakers and I had it again writing the Fantasy, the first mainly woven with political and sociological philosophy and the second with political and spiritual scrutiny. I said to my father once, long before I'd gotten brave enough to openly speak about my books as if they were something promising, "You know how I know I'm writing a good villain?" (I guess the arrogance had still already progressed to Stage 2 - Fermentation. When you're just beginning to realize you like what you produce and also realize it's no good if no one else realizes that you like it.) To continue -- "Because I agree with what he's saying."
I found I actually agreed with some -- not all -- all what my villain was saying. Let's take a look at him. Walters. (He can be found in the "Fun Stuff" tab). I hesitate to bring up the Fantasy villain as his identity is a bit more of a surprise but I will say that I agreed with him too -- in allowing predetermined policies and expectations to limit the exploration of what we are capable of.
Now then, for the authors out there, let's break up what builds a great villain -- both logistically and aesthetically.
1) A reason
What makes him the way he is? He wasn't born evil. How do you justify his actions? How do you agree with him? Because don't we all have darkness? Are they not just the ones who took it too far?
2) A power
Something he/she can do that the protagonist cannot. A power (think consequential rather than magical here) he wields that the hero is forced to confront and overcome. And, more importantly, something that makes the villain, and only the villain, suited to that power
3) A badass trait
I'm Breaking (<--!!) my professionalism here and telling you to just flat out make them badass. Helpful, I know. But it's true. Give them an intense trait. Such as a metal/mechanical heart (Walters). Such as the mask ^
Or a weapon. Or a feature. Or even a catchphrase that you can trademark your villain with.
Now, I'm not saying every villain needs to be oozing radio-active waste or having an eye patch and a scar from his ear to his knee. Sometimes, the best villains are the ones you don't expect, like Grandma or a 17 year old, ambitious kid. But DO let the reader make this person real and intense. Otherwise, you have no stakes. Nothing to be afraid of.
Villains, you will never win. You will always be triumped by our heros, the ones who we want to be. The ones we hope we are in some ways. Good will always flood away evil.
But we ARE afraid of you.
Because in a way, we agree with you.