Jaqen’s reference is the Faceless Men cult from Game of Thrones fictional universe The Faceless Men are a cult of religious assassins that worship the Many-Faced God, and they believe that death is a merciful end to suffering. For a price, they will grant the "gift" of death to anyone in the world, considering the assassination a sacrament to their god. They consider themselves servants of the Many-Faced God, a god of death who is unknowingly worshipped by all religions in the world, in the form of one god or another. The weirwood Face for the Old Gods of the Forest and the Stranger of the Faith of the Seven are two such deities. Faceless Men are trained to relinquish their former identities and become "no one", which allows them to become entirely different people, all in service to the Many-Faced God. Killing for personal gain or out of anger or hate is forbidden to Faceless Men. As the Faceless Men forsake their identities in the service of the Many-Faced God, they only assassinate targets they have been hired to kill and may not choose who is worthy of the 'gift' by themselves. The guild of assassins is based in the Free City of Braavos, though their members range far and wide across both Essos and Westeros. They command exorbitant fees but have a reputation for success that is unparalleled by any comparable organization.