In the movie Equilibrium, the Grammaton Clerics are the elite enforcers of the government of Libria, tasked with hunting down and eliminating "sense offenders," those who refuse to take the emotion-deadening drug known as Prozium. They are particularly well known for their training in the firearm-based martial art known as gunkata.
John Preston, the protagonist of the movie, is a Cleric who comes to turn against his government after rediscovering the ability to feel.