The head of the Unmentionables, the secret police of Patrician Winder's Ankh-Morpork. A thin, fanatical man who believes that criminal tendencies can be determined by measuring the shape of a person's head with callipers. He is a true believer in his own system, which conveniently labels as criminal anyone who opposes the government. His methods include torture, arbitrary arrest, and disappearance of dissidents.