Crime Boss

The unnamed Crime Boss is the main protagonist of the mobile game Batman: Arkham Underworld, who begins to takeover the Gotham City underworld.

Arkham Underworld Incident
The aspired criminal began their plans in taking over the Gotham City criminal underworld and becoming a major crime boss, and enlisted in several Gotham supervillains such as Two-Face, Poison Ivy, Harley Quinn, Scarecrow, Bane, Killer Croc, and The Riddler in order for them to succeed. This put the crime boss into conflict with major crime lord Carmine "The Roman" Falcone, as well as the Gotham City Police Department and the vigilante Batman.

It is unknown what became of the crime boss afterwards.

Trivia

 * The crime lord's activities are said to have taken place "nine years ago", which is presumably before Arkham Knight, although this would have placed his reign during Batman's third year, following Batman: Arkham Origins.