One of the most iconic heroes in all of literature is famed sleuth Sherlock Holmes. And his adversary, Professor James Moriarty, is one of the most well known villains in all of literature, and he's gotten a reputation in film now too since both the Sherlock Holmes movies and the show Sherlock have featured him. So what is so freaking cool about this guy that makes him so prolific? Well, in my opinion, it's the fact that he is everything that the hero is, except that they stand on different sides of the law. We get the sense that he is Sherlock in a different life. In the Guy Ritchie movie, they have the same level of intellect, have similar habits and can even play the same mind games with each other. In the series Sherlock, it's a little different, they are almost black and white, total polar opposites. Sherlock is a detective, Moriarty is a criminal. Holmes is very stoic, Moriarty is extremely flamboyant. It's a classic case of how people can be similar and yet so different. In both the movies and the series, I could almost see them being friends had they not been standing on different sides of the line. They even have a respect for each other and admit that they are the greatest adversaries they have faced. So, I guess what makes Moriarty such an iconic character is not so much he himself (there are plenty of other characters like him), but the complex relationship that he shares with Holmes.