In most stories, someone causes the problem that vexes the main character. This character is called the antagonist.

Examples of well-known antagonists include the Wicked Witch of the West in “The Wizard of Oz,” Sauron from “The Lord of the Rings,” and Scar in “The Lion King.”

Usually a story is not told from the antagonist’s perspective. In fact, often the antagonist is a flat, cardboard character whose sole reason for existence is to cause trouble. This was one of the complaints “Star Trek” creator Gene Roddenberry had of the Klingons in “The Original Series.”

Obviously the main character needs to be the focus of your story, and so the antagonist in contrast will not be as developed. Still, you want to think a lot about the antagonist and give him deeper motives than greed, lust or evil. He’s arguably the second most important character of your story, after all, and the reason why there’s even a story to tell. By developing a backstory for the antagonist’s motivations, you can create thematic tension. The antagonist’s motivations can be paralleled with and contrasted to the protagonist’s motivations and decisions.

As with the main character, you should know what your antagonist looks like, his strengths and weaknesses, his likes and dislikes, what motivates him, his parents and schooling, who he’s dated throughout his life, the foods he enjoys and hates, what he does during his free time, how his apartment is decorated, places he’s visited and places he yet wants to go, and more. You should know your antagonist almost as well as you know yourself.

In addition, sometimes, the antagonist is not a “real” person but an element of nature or some competing idea in the main character’s internal conflict. Often these antagonists take on a life of their own, becoming characters in their own right.