Dorfl is a member of the Ankh-Morpork City Watch. He is a golem. Originally created, like all golems, as a silent, obedient worker, Dorfl played a key role in the golems' attempt to 'free' themselves by creating a king golem. Dorfl was a suspect in the murder of Father Tubelcek; it later transpired that Dorfl found the man dying and, attempting to save him but not understanding how people worked, put holy words in the priest's mouth. Dorfl was severely damaged in the fight with the golem king, but rebuilt by Chalky the troll and given a voice. He helped Sam Vimes apprehend the poisoners of the Patrician and then joined the Watch.
Dorfl never sleeps, and being made of clay he is handily fireproof. This is useful for putting out blazes (Jingo) or merely for surviving divine bolts of lightning. Dorfl is an athiest, who claims he will believe in any god whose existence can be logically proven. This position has gained him a somewhat unlikely friendship with Omnian fanatic Constable Visit.
Dorfl is presumably the founder of the Golem Trust, and spends his pay buying and freeing other golems. Like all golems, he Speaks With The First Letter Of Every Word Capitalised.