A man known only as "The Boss" was a gangster in Gotham City.
The Boss ran a group of criminals headquartered aboard the cargo ship Warnham, and operated out of the Hathcock Shipping Co. warehouse located by Gotham City's docks. In a botched sting operation by the Gotham Police Department, some of his thugs were able to capture the Batman and bring him back to the warehouse where they strung up the masked crime fighter from a rafter. The Boss reasoned that taking Batman alive was worth something.
However, this soon turned out to be an error in judgement, for not long after having regained consciousness, Batman casually inquired as to the whereabouts of the criminals' boss. The thug in charge, thinking nothing of it as the Batman was secured, revealed The Boss' location as being just outside aboard the Warnham's deck. Having obtained this information, despite being deprived of his utility belt, Batman easily escaped his bond with a knife concealed in his glove and turned on his captors, aided by Renee Montoya. The Boss dispatched more of his men to engage the pair, but with the eventual realization that the tide was quickly turning against him, his seafaring headquarters began its departure forthwith from Gotham. Yet this hasty getaway was thwarted when Batman rammed a forklift at high-speed through the boat's hull, having commandeered it from the enraged thug in charge who had tried to run the Dark Knight over. With his cane and luggage bag in hand, a final effort at escape on foot was cut short by Montoya who caught The Boss, to his fright, in the mechanical claw of a loading crane.
The Boss was presumably arrested, and has not been seen since.
The Boss' visage (save for his monocle) remains shrouded in shadow for most of the episode, save for two very brief moments as he tries to escape. His identity is never revealed.