On Writing Good Antagonists

So you have your villain. He's got a death ray and a curly mustache and he only says mwahaha unless he's got the hero trapped. In which case he'll be giving his monologue. He's evil and dastardly and is not a character or a person, rather a prop, an obstacle used to hinder your hero's progress.

I'm gonna have to stop you right there. 

No.

Stop.

Wrong.

A villain/antagonist is just as much a person and a character as your heroes/protagonists and supporting cast. 

A villain needs to be just as human (even if they're an alien or fantasy race) as the hero is. Because your villain needs to make the audience realize that the potential for "evil" (like the potential for "good") rests within everyone. (Just don't get me started on the black and white bull crap. It's never as simple as good and evil. And I especially hate it when people automatically assume that Chaos=Evil and Order=Good. Why, I associate chaos with creativity and curiosity and the questioning of society, and aren't all those things good? I address this issue many times in my stories, which will eventually be posted here.)

A villain needs to be human because it's never as simple as black and white (see above.)

And so a villain needs to be just as three dimensional as a hero. 

-Give them thoughts and ideas and emotions 

-Give them interests and hobbies and a job or position in life

-Give them legitimate character development. They don't exist in a vacuum, the events of the story affect them too.

-Explain their motive. Don't just give them a motive with no "why?" (Why do they want power? Why do they hate humanity? Why do they want to see your hero suffer for all eternity?)

-Give them positive qualities as well as negative.

-Make them just as diverse as the heroes. The potential for good and evil rests within everyone. This means Heroes should be diverse, but so should villains. See also my post about diversity!

And here are some optional things you can do to make your villain human.

-Give them friends, or a love interest. Not people they pretend to be friends with just for personal gain, or people they befriend to anger the hero. Give them actual individuals that they care about and enjoy the company of!

-Give them a back story! While their backstory does not excuse their current actions, it can be useful for several reasons. Making them sympathetic makes people realize that they are a person with feelings and not an object or a prop. Giving them a backstory also makes them important. Your hero presumably has a backstory that shaped who they are today. Your villain should have one too.

-Maybe your villain starts off as one of the good characters, but turns bad later on. This is similar to the backstory, except it gets to be told in real time as opposed to in flash backs.

-Or maybe your villain doesn't stay the villain forever. Maybe they somehow turn good, taking a long arduous path to redemption for whatever reason or another, but they did it. They're good now. And they openly admit their mistakes and are shown struggling with their past self.
-Perhaps your villain has a code of honor. Yeah they're bad, but maybe there are some things even they won't do. Like hurt a child. Or fight the hero without first trying to reason with them. Maybe your villain is willing to listen to what your hero has to say before they fight them. Maybe they'll actually consider what the hero said for half a second!

-Give your villain a family! Show them interact with parents, spouses, children, siblings, etc. And make those relationships real. Don't just say "oh, he's my older brother." Make it look like these characters actually grew up together!

That is all.