Karl C. Rocker is a former Police Commissioner of the New York City Police Department. A tall man usually dressed in a dark suit with NYPD lapel pin, Rocker is often described as "weary-looking" with tired eyes and a low gravelly voice.
As Commissioner, Rocker was well-respected by the rank and file officers for not allowing political interests to influence him. He guided the department through several high-profile incidents, including the Surgeon murders, the devil killings and the Wayne Buck mob, the complete burglary of the American Museum of Natural History's diamond hall, a series of murders purportedly committed by a highly decorated FBI agent, and the brutal killing of a New York Times reporter.While helping the mayor assemble a task force to facilitate trust and cooperation between the mayor's office and his own, an FBI sting operation caught a telephone conversation between Rocker and tech mogul Lucas Kline. Kline offered to donate five million dollars to the Dyson Fund—which provided financial and emotional support to families of fallen officers—on the condition that Captain Laura Hayward not be appointed to the task force, thanks to Kline's personal vendetta against Hayward's boyfriend, Vincent D'Agosta.
Rocker played along for the benefit of the fund, but the fallout destroyed the careers of both Rocker and Kline, while the task force itself became just the bureaucratic nightmare that it was supposed to eliminate.
- His first name is changed to "Henry" when he appears in Brimstone.