As a Book Doctor, I’m always concerned about the Nutrition of the Novel. If you don’t feed the characters enough backstory, they will be weak or flat. But if you put too much of their backstory into in the novel, it becomes overweight, or even obese. The proper weight of the novel depends very much on the genre, so be sure you know the proper weight for your book, and feed your characters accordingly.
What does it take to make a good character? A good backstory. You need to know where this character comes from, who they are, what kind of family they come from. How did their parents fit into society? Were they royalty or pig farmers? Did they want this child for the love of children, or from the need to have another farm hand to feed the pigs? Are both parents living, or is this an orphan? Did they have a tortured past?
One way to feed your character is to sit down at the computer, focus on that character, and just start typing. Type whatever comes to mind as you think about this character. Don’t worry about editing, this won’t go into the novel, this is only backstory. As for how much backstory goes into the novel, see my post, Upper BackStory Pain.
Writing about your character this way frees you of any constraints put upon you by the genre. You don’t really have to worry about proper formatting, or getting the dialog right. Just type it out, whatever the character says to you. Sometimes this will be a very dry description, and sometimes it comes out as a scene from their childhood. You can change it if the novel requires it, but the important thing is for you to get to know the character.
I recommend this as a good exercise for all the major characters, as well as most of the semi-major characters in the novel. Sometimes the best enemies are those who used to be friends, or have a family relationship. Luke Skywalker and Darth Vader come immediately to mind. Sometimes the villain is the former pupil of the mentor character, (again, Darth Vader and Obi-Wan). Whatever relationship you form between the protagonist and the antagonist, make sure you, as the author, understand it better than any of your readers ever will.
To write a good villain, they need to be believable, and usually, they don’t think of themselves as evil. Voldemort, for example, didn’t believe himself evil. He didn’t believe there was such a thing as evil, only the strong and the weak. In the movie Hero, the Emperor believed he had a noble goal, to unite the lands, for the good of all. Today, that Emperor’s legacy is one of the world’s greatest Superpowers. Lex Luthor was trying to make money, and didn’t care who he hurt to get it.
It’s true, some characters enjoy hurting others. For them, this is a learned behavior. If you, as the writer, don’t know how they learned this behavior, or why, then the reader likely won’t see the villain as believable, and the novel will lose its appeal. Creating an antagonist is easy, but creating a healthy villain, who can stand up to scrutiny, and be more than a punching bag for the hero takes proper nutrition and backstory.
Sometimes you can get away with the antagonist having no prior relationship with the protagonist, such as in The Lord of the Rings. Sauron is so ancient that any relationship he has with any mortal being is long since lost to history. The three elven ring bearers knew him, but the series never reveals which race Sauron came from. Was he an elf, a man, or a dwarf? I wish I could ask J.R.R. Tolkien, but now I never will. But I want to believe that he, as the author, knew more about Sauron than I do, as the reader.
In summary, healthy characters are one ingredient to making a healthy novel. Make sure they have a sufficiently healthy backstory before you begin writing the novel, or you’ll likely find yourself doing quite a bit of rewriting. Feed your characters enough backstory for them to grow healthy and strong before they take on the world.