Origin

The Gambler is a hit-man hired to kill X.  Hired by the Llewellyn Brothers Amos and Jonas the Gambler was sent to kill X but the Llewellyn brothers were killed by X moments afterwords.  Undeterred the gambler went to kill X anyway.  X new he was on his trail and the two played a game a cat and mouse to take each other.  Unlike most villains the Gambler is not given the traditional warrining by X making him an instant target.