Brad Johnson has written a great article for Script Magazine about how villains can make compelling protagonists. He uses Dexter as a prime example.
So you think that bad guys can only be Antagonists? Think again. They’re just as multi-faceted as the good guys these days. One day, when you least expect it, you’ll realize the script idea rolling around in that brain of yours is crying out to have a bad guy protagonist at the heart of the story. But how do you put someone like that at the center of your script and expect the audience to go along for the ride? Audiences like to cheer for the good guys, right? Actually, what they really like to cheer for is a character with whom they identify. On some level – any level – if the audience can catch a glimpse of themselves inside the character, then you’re golden.
The most effective way to successfully establish a traditional Bad Guy as the Protagonist of your script is to establish a set of rules for them to follow. They may not involve a traditional moral code, but your Protagonist still needs to have a set of laws, even self-established ones, that they adhere to if the audience is going to care about them.
Gangsters are a great example of this. Think about Don Corleone in The Godfather. He’s the head of a mafia family. He kills people (or has people killed) and does all other kinds of other unsavory things. But the audience likes him. Why? Because he’s shown early on to be one of the “good” gangsters when he refuses to take part in the drug trade.
And that’s the key to establishing a bad guy as your Protagonist; they need a personal set of rules. Something that makes it okay for the audience to like them. Something that lets the audience feel that it’s okay to identify with them. There are a lot of examples out there, but let’s start by taking a look at the most literal version of this kind of Protagonist: Miami’s most loveable serial killer.