Lately I've been listening to Johnny Cash songs. Many of his tunes are about the exploits of criminals like "Folsom Prison Blues", "Cocaine Blues", "25 Minutes to Go" and "Hardin Wouldn't Run". Cash had an ability to tell the story of a criminal better than anyone (even though he served absolutely zero time), but his lyrics follow a little known genre called rogue literature.
Rogue literature is defined by the "Dictionary of Literary Terms and Literary Theory"(Penguin Reference) as: "a genre concerned with the underworld and thus with criminal and quasi-criminal life and activities." It was more popular in the 16th and 17th centuries with works like Hye Way to the Spyttel House by Robert Copland (ironic name), Caveat for Common Cursetors by Thomas Harman and Lanthorne and Candle-light by Thomas Dekker. I would argue that it has found its way into the contemporary world through films such as anything directed by Quentin Tarantino, Elmore Leonard's Get Shorty novels and Donald E. Westlake's novels written under the pseudonym of Richard Stark which featured a protagonist named Parker. In the first novel of the series entitled The Hunter, Parker embarks on a relentless quest to kill the man who left him for dead during a heist.
Writing a rogue novel seems like an interesting concept, but how far does one go down the dark path as a narrator until we find ourselves cringing at the evil we are capable of creating? I don't know if I have the salt to write such a novel and make it seem real. I guess I'm just not bad enough. Johnny Cash found inspiration in his own dark nature that he said "only June (his wife) could keep away." I can create vicious villains that have fatal flaws, villains so wicked that they maliciously become perfect obstacles for the hero. I use the villain's traits to shine a spotlight on the characteristics of the hero which then endears readers to that protagonist. I would find it difficult to write a novel in which the protagonist is cruel, vile and nasty. It makes for an interesting read, and takes readers down a path they would otherwise not travel, but I'm sure it would be worth attempting sometime.
Possibly you are reading this and you are writing a rogue novel. My advice to you is that a villainous protagonist will have the same characterization as a typical hero or even an anti-hero, but without all the baggage of needing to save the day or be a "good guy". I would argue that the villainous protagonist has different kinds of baggage like: What has made the hero so evil? What is the motivation for continuing a life of crime? Is there a moment where the hero might have a choice to do good but does evil and why? Considerations like this will make for a multi-layered character that will be exciting to read. A character of this design will keep us guessing, and that is worth the time it takes to follow an evil protagonist down into that blackened cave.