My first reaction was that he was crazy, because the things he does are violent and shocking, so they could only be the work of a crazy person. But the more I thought about it, the more I realized that while his actions might be crazy, he was scarily sane. He could rationalize each and every one of his violent acts. He understood the consequences, and willingly accepted them.
We've all heard the expression that every villain is the hero in their own story. In all of my other projects, I could see that clearly, primarily because my antagonists weren't inherently evil, they just wanted something different than the main character, and they had their own reasons for wanting it.
But in this new project, the bad guys are BAAAAD. And I've found that bad guys who are truly evil are hard to write without making them feel a bit like stereotypical super-villains. Now that I knew my bad guy wasn't just a lunatic with an agenda, but a person with reason, I had to find a way to humanize him. And that's when I realized the comics had it right: my super villain needed an origin story.
Every good super villain needs an origin story. If we can catch a glimpse into the emotional trauma or events that shaped the way the character views the world, we can begin to, if not empathize, than at least start to understand how the character could do such inhuman things. And, traces of his humanity need to show through at some point too.
The bottom line: my bad guy has too be more than his bad acts. He's a son, a lover, a person who
needs and wants love and acceptance as much as anyone else. And maybe it's his need for love and acceptance that allows him to be swayed toward certain actions. Maybe he's conflicted about what he's doing. Maybe he tries to stop. But what if stopping leads to the death of the one person he really loved. How would that guilt shape him?
Going through the exercise of trying to understand every aspect of my bad guy's motivations helped me to understand his actions as something more than just crazy acts of a crazy person. These were desperate acts of a person who wants to be loved.
And that is a lot more interesting to write!