To me, no story is complete without a compelling antagonist, someone I can really hate. The most important part of it, though, is that they’re still believable while I’m hating them, that they have their own rich inner lives and motivations for whatever it is they’re doing. I’ve heard it said that the villain needs to be the hero of their own story, and I think that’s pretty accurate to both the antagonists that I love to read and the ones I love writing.
The next step, then, is making the antagonist have their own character arc, a progression from the beginning to the end of the story. For example, Voldemort is terrifying, yes, and of course he hits the first piece of advice strongly. He honestly believes that he’s on a mission to “purify” the witches and wizards of Britain, saving them from themselves. But he misses the second. Throughout all the million or so words of the Harry Potter series, he doesn’t really grow or change. He’s a static villain, which works for the story that JK Rowling set out to tell. But he doesn’t stay with me after the close of the book the way that Snape or even Draco do.
To give an illustration of the kind of arc I like to see, I want to contrast two antagonists from Tamora Pierce’s works. The first is Lord Wyldon from the Protector of the Small quartet. From the first page of the books, Wyldon is strongly opposed to Kel’s enrollment in page training. Not because he has anything against her personally but because of his commitment to tradition and his desire to train the best knights possible to protect the kingdom. He honestly believes that her presence in the castle will be a detriment to both Kel and to his other students, and so he uses every tool at his disposal to urge her to leave. Therein we have the first ingredient of a successful antagonist: a complex inner life and self-justification for the wrong that he’s doing.
The second part is what makes Wyldon stand out to me, though. Throughout the series, Kel chips away at his objections. She proves herself as capable as his other students, grudgingly earning his respect, and Wyldon slowly finds himself in her corner, leaving room for a more dire villain.
The other strong example that I’ve pulled from Tamora Pierce’s work is Bennat Ladradun from Cold Fire. Ben is the polar opposite to Wyldon–he starts as one of the heroes. Then, slowly, for what he feels are good reasons, his moral compass starts to shift. He sets a fire, meaning it only as a training exercise for the firefighters he’s been working with. Then he sets another, feeling that the city’s gotten lax in its response. Then another, and someone dies. His fires grow larger, the traps more deadly, and the excuses more paper-thin. Before Ben himself can realize what’s happened, he’s gone from a desire to help to a desire to kill.
It’s a terrifying thing to read the progression, to see someone so normal and respected become a monster. And it’s something I wish more authors would do, make their readers follow their villains deeper into the shadows that they’d thought possible, all in the name of what they feel is a good goal.