(Please excuse me as I build up to something relevant. I drafted the outline of this book more than a year ago, clearly with something in mind to say about each chapter, and it's going to take me a bit to get there. This should be a lesson on fast drafting! Writing it all down while it's clear in your mind.)
So pretty popular trend right now, the antihero.
The antihero story is what you'd be writing if you were to write your story from the point of view of your antagonist. Of course that would make him the protagonist, and all the the protagonists then become antagonists. Okay, that is just way too convoluted an explanation.
The antihero is the protagonist of your story, but he or she is not someone a reader would easily identify with. He isn't ordinary Joe or plain Sally. He's an awful person, morally, whether he recognizes it or not.
In the antihero story, when things go wrong for him, it's because the good guys are winning. And when things go right for him, it's generally not a boon for others.
The trick with making a successful antihero story--one that people would actually want to read--is that everything about the antihero can't be annoying or immoral. You must have large parts of his or her character that readers will consider noble.
The antihero is a dance between good and evil, a delicate balance between surprising the reader while not distancing them. It's powerful when done well, and difficult when executed without care.
It's hard to say much more on the subject-the antihero is more than a hero with a bad attitude. He or she has deep wounds and insurmountable flaws. His arc will not be one of redemption, but he might find smaller insights in the course of his story.
As always, it's a great idea to seek out similar stories, study the genre. Some famous examples-Walt from Breaking Bad, Maleficent. Many, many more in the form of books. Post your favorite antihero here!