Sarge was the former head of the police operations that Ben Birdland (now known as Big Band) and Irvin was a part of. In truth, he was also involved in the Medici's gambling operations.
He and his corrupt underlings tried to get rid of Ben for uncovering their plans by beating him senselessly, leaving him for dead, but he managed to recover thanks to Dr. Avian's efforts. After Big Band busted up his gambling operations, he is no longer seen as useful to Lorenzo, and he is quickly disposed of. It is unknown where he is now, but he is likely dead.