The Guild of the Faceless Men is a religious society that worships the Many-Faced God, a god of death. The Guild originated in the volcanic slave mines of Valyria. Their founder came to believe that Valyria's diverse slave population all prayed to the same god of death in many different incarnations. The Guild believes that the death gods of all religions are faces of a single, Many-Faced God.

In the Guild's House of Black and White, followers wear black and white robes and perform religious duties for the community, such as tending to the dead. The House contains a public shrine with idols of many death gods, including the Stranger of the Seven, but there are no formal services. Some visiting worshipers drink from a black cup that provides a painless death. A phrase associated with the cult of the Many-Faced God is "valar morghulis," translated from Valyrian as "all men must die"; a response to this is "valar dohaeris, "all men must serve" is most likely the translation. In Feast for Crows the Kindly Old man tells Arya: "All men must Serve beneith this roof. Valar Dohaeris is how we say it here."

Followers of Him of Many Faces consider death to be a merciful end to suffering. For a price, the Guild will agree to kill anyone in the world, considering this contract killing to be a sacrament of their god. An elite group of followers within the Guild, called the Faceless Men, are trained to perform this task. Despite their name, Faceless Men are occasionally women. They possess magical abilities that allow them to change their appearance at will. Part of their training includes discarding their true identity and thinking of themselves as "no one". They use a variety of methods to kill their targets, including a poison called "the strangler". The cost of their services depends on the importance and security of the target. The assassination of a king could cost much more than the hiring of an army.

Faceless Men:

• Jaqen H'ghar, posing as a Lorathi criminal claimed by the Night's Watch.
• 'The Waif', a woman with the permanent appearance of a child in the House of Black and White
• 'The Kindly Man', a teacher of novices of the Many-Faced God