Excerpt from an Astro City Police Department file:
Real Name: Thomas Aloysius Gunn
Once a soldier in the Forgione crime family, "Tommy" Gunn moved into the vacuum created in the wake of the Blue Knight slayings of most of the Forgione upper echelon, and built the remains of operations there into a smaller but growing operation.
Gunn lost his left hand in a 1963 battle with the Silver Agent, and had it rebuilt by persons unknown; he now has a mechanical hand, each of the five fingers of which is a gun barrel capable of automatic or semi-automatic fire, along with other functions.
Gunn has been known to hire super-powered enforcers, but prefers to work with traditional organized-crime structures and capabilities, save for his "Gunbirds," armored cybernetic soldiers with built in weaponry. The Gunbirds should be considered both extremely dangerous and loyal -- they may have mental override systems that allow Gunn to kill them at a distance if they even begin to act disloyally.''