by Scott Rhoades
It's fun to make your bad guy an evil villain, wicked through and through. The kind of guy who ties young maidens to railroad tracks for the fun of it, and throws the hero on to the slow-moving conveyor belt at the saw mill, just because he can. You know: the kind of bad guy who spends his time laughing maniacally while he twirls his 'stache.
This kind of villain is motivated solely by the fun of being e-vile. Yeah, he might want something. Maybe he wants the hero's girl. Or the gigantic diamond. But he only wants it for the sake of being wicked. And he would have gotten away with it too, if it weren't for those pesky kids. But this kind of villain is one dimensional, and doesn't work well in most books.
All an antagonist is, really, is somebody who either wants the same thing your protagonist wants, or who has a good reason to stand in the way and keep the good guy from achieving his goal. The antagonist could be a good person, but we're rooting for the other guy, so we don't like him. The antagonist could even be a better person than the protagonist.
The important thing when you're writing is to keep the motivations of both the protagonist and antagonist in mind. Chances are good that your bad guy wants to stop the good guy from winning for reasons that he thinks are good. He might be right, or he might be misguided, but he's convinced.
The bad guy almost always sees himself as the good guy. That means he sees the good guy as the bad guy.
I'm sure Sauron thought he was doing Middle Earth a favor by taking dominion, while Saruman thought he was doing good by trying to stop the Black Lord and taking the power himself. Darth Vadar probably saw the Jedi as nefarious rascals, upstarts who wanted to thwart his plan to make the universe a better place.
My favorite example is politics. Whatever your political position, you believe your candidate is right and the others are wrong. The others see their side as right and the others wrong. For the most part, all sides believe they are going to make the world a better place if they win. If you are interested in politics, you no doubt see a good side and a bad side, and think of people on the other side as misguided at best, but most likely as people who are out to intentionally destroy the country. Guess what. The other side sees you the same way.
That's how it is with your antagonist. He believes he is right, that's why he is so determined to stop your protagonist from succeeding. During the course of the story, your reader might even start to wonder if the antagonist is right, because he clearly means well and is not such a bad guy. Meanwhile, your protagonist's flaws cast doubt on just how good a guy he is.
When two people want the same thing and both believe they are right, you have interesting conflict. As a writer, you can play with that. Maybe your narrator is unreliable. Maybe you play your reader so he thinks the bad guy might actually be the better man. Maybe your good guy does something that's easy to interpret as evil, even if his motivations seem honorable.
In other words, your antagonist is the good guy, at least in his own mind. His wants are every bit as valid as the protagonist's. It's just that he wants the same thing.
If you keep that in mind, you are sure to have an interesting story.