Joker

The Joker is one of the most iconic villains, not only in the history of Batman, but in the history of fictional villainy. He's a crazy badass. He became one of the mainstays of the Arkham series, and was perhaps as important to that series as Batman himself. Not even death could stop the Joker.

 This iteration of the Joker comes from Arkham Origins, the weakest of the Arkham titles. I tend to enjoy this version of the Joker the best out of the series, at least visually. Here he's younger and looks a little more sinister, as opposed to the older versions of the Joker which seemed to focus more on his wackiness.