One thing that I love in literature and media is a realistic well written villain or antagonist.  I like when the antagonist becomes a willing, or reluctant, companion to the hero(s), ala Spike in Buffy the Vampire Slayer.  I like when the villain is unrepentantly evil, such as the Master on Doctor Who.  A well written villain is a marvelous thing to watch and to read.

Recently, Surasmel over at Ink Out Loud wrote about just this topic in a post amusingly titled “My Whole Writing  Class Thinks I’m Crazy“.  I can understand the human desire to want redeemable villains, to want a logical reason why a person would act so heinously.  You can give your villain that tortured back story that explains how they got to be the way they are, but sometimes you (and your characters) have to step out of your comfort zone.  If you need to, do some research.  Watch crime dramas.  Documentaries about serial killers or shows that get into the suspect’s head, like Criminal Minds, can be great resources for ideas.  There are hundreds of books out there about criminal psychology.  Research, find your favorite villains, study what other authors do.  If you do, your writing will benefit and your readers will thank you.