The dictionary defines evil as morally wrong or bad; immoral, wicked, evil deeds, an evil life. That’s a bit redundant and circular in some places. Still, it’s a good definition of the word. Wikipedia says it is the absence or opposite of that which is ascribed as being good. That’s a bit pompous, but still also a good definition.
All good fiction has conflict. There are many layers to conflict. There can be conflict in the desires of the characters, conflict between ideals, and the type that I will be discussing today, the conflict between Good and Evil. You have the hero or protagonist against the villain, or antagonist. The villain represents Evil. A villain portrayed as completely evil is not a believable villain because he or she should have his or her own set of morals. To create a good villain, a writer needs to set up that set of immoral morals.
As much care needs to be taken with creating a villain as is taken with creating a hero. Just as we love a flawed hero, a villain with a few redeeming qualities is a good, realistic villain. Can the villain be redeemed? Anything is possible in fiction. The story elements leading to that should be set up realistically though. the writer, in this instance, should ensure that the villain is portrayed as evil at the beginning, so that he or she is easily seen as a villain. Then in the middle the villain could re-examine his or her values. Only then can the writer redeem the villain at the end. that’s hard to do, but not impossible.
So what is evil? What makes your villain believe that he or she is right when he or she is amoral or just immoral? In other words, what beliefs make your villain evil? What redeeming qualities does he/she have that make his/her evilness even more pronounced? You need to create a moral code for your villain just as you do for your hero. What does your villain want? Whatever it is, it should be the total opposite of what your hero wants.
It’s a good idea to create the two characters together so that you can match them. Sometimes it isn’t possible to do that, of course. When that happens, just have your hero’s chart open and refer to it when you create your villain. That works well for characters in a series.
Conflict drives fiction. Characters drive conflict. Creating good and evil characters is important. don’t skimp on this part of the work and your story will be the better for it. study the books or movies that had you hating the villain and see what made those villains work. you can adapt that to your own villain. Good luck and keep writing.