Many-Faced God

"There is only one god, and his name is Death. And there is only one thing we say to Death: 'Not today'."

- Syrio Forel

The Many-Faced God (alternatively known as the God of Death) is a deity worshipped by the mysterious cult of assassins known as the Faceless Men, who are headquartered in the Free City of Braavos.

Beliefs
The cult of the Faceless Men worships Death, which they believe is the only god. The cult is actually a syncretic religion: they believe that Death is unknowingly worshiped by all religions in the world, and simply under different names. Every religion either has a god of death (in polytheistic faiths), or has a god with dominion over death (in monotheistic faiths): the cult believes that all of these other gods are simply different aspects or "faces" which Death has revealed Himself to humanity with - hence why they formally refer to their deity as "the Many-Faced God".

There is no one symbol of the Many-Faced God, simply the icons used by death gods in other religions. The temple of the Faceless Men in Braavos, known as the House of Black and White (due to the color of its doors), contains a large public sanctuary with statues of death gods from all other religions displayed equally: the Stranger from the Faith of the Seven, a carved Weirwood Heart tree face for the Old Gods of the Forest, the Drowned God, the fiery heart of the Lord of Light, the Black Goat of Qohor, the Weeping Woman, and the Lion of Night. Icons from lesser religions and cults are also honored in the House of Black and white, including the Hooded Wayfarer, Bakkalon the Pale Child, the Moon-Pale Maiden, and the Merling King, and many others.

The Faceless Men see death as a gift from the Many-Faced God to end human suffering: either to euthanize the sick or bereaved who can no longer stand the suffering of living, or as a "gift" to kill those who are causing suffering for others. As a result the cult of mystic assassins view themselves as Death's servants, strictly bound to His service. In their at times inscrutable beliefs, they feel that they are only helping to carry out Death's will, and cannot choose their own targets (for personal reasons, such as revenge): they can only target those whom death has selected - the targets of assassination contracts they have accepted. The Faceless Men practice extreme self-abnegation, each one believing that they are "no one", with no personal desires, and living only to serve the Many-Faced God.

The Faceless Men have no known prayers or worship services - only their actions, by committing assassinations. Their only "clergy" are the Faceless Men themselves, above lower ranking acolytes and novices serving in the temple. The House of Black and White's public sanctum is also open to any who are in pain and seek death: they are given a drink of water from a poisoned cistern, which grants them a gentle and painless death. In return the Faceless Men collect their corpses to use their faces as disguises (by using their magical shapeshifting abilities with it).

Quotes
"That man's life was not yours to take. A girl stole from the Many-Faced God. Now a debt is owed."

- Jaqen H'ghar to Arya Stark

In the books
In the A Song of Ice and Fire novels, the "Many-Faced God" is alternatively known as "Him of Many Faces", yet never the "God of Death", and is worshiped particularly by the Faceless Men, a guild of assassins based out of the Free City of Braavos.

The Faceless Men believe that they only help bring death to targets of the Many-Faced God - they do not choose the targets themselves for personal reasons such as revenge, they only kill the targets of assassination contracts they have accepted. However, the Faceless Men will at times refuse a contract if they feel that it clashes with their strange and at times inscrutable religious beliefs. Other times, they choose bizarre "payments" according to what they feel is due: sometimes, if a powerful lord asks them to kill the child of one of his enemies, the Faceless Men give as their "price" that in return they will kill the lord's own child (the lord can reject this, but it also means rejecting the entire contract). Daenerys was a princess and royal heir, so understandably a contract on her life would have been expensive - but at other times the Faceless Men might set an exorbitant price for an assassination contract, based on their own beliefs about how "important" the target is: a poor widow who wants to kill a wealthy insurance salesman that defrauded her will only be charged a modest sum she can afford, but a nobleman who wants to kill his own brother simply out of greed because he stands ahead of him in line of succession will probably be charged much more.

The death-worshiping cult of the Faceless Men and the Many-Faced God actually originated in Valyria, in the the vast slave mines under the Fourteen Fires. The thousands of slaves from a hundred different lands faced death on a daily basis, and over time, the belief developed among some of them that while they came from many different lands and followed many different religions, all of these religions were fundamentally the same, because they all worshiped death in some fashion. In time this turned into a syncretic belief system worshiping Death as "the Many-Faced God". They started out by giving the "gift" of death to slaves who were suffering particularly horribly in the mines, to ease their pain - and in time, they learned to surreptitiously give the "gift" to some of their Valyrian masters as well, becoming skilled assassins. Many centuries later, after Valyria was destroyed, the surviving Faceless Men relocated to Braavos, which was founded by ex-slaves who had escaped from Valyria. The Braavosi welcomed them because they had both formed in opposition to the Valyrians, and in Braavos the Faceless Men established a firm headquarters where they continued to operate for the next four centuries.

There seems to be some confusion both in the books and the TV series between the God of Death and R'hllor, the Red God. It stems from a piece of dialogue spoken by Jaqen H'ghar in both mediums, in which he refers to the god he worships (presumably the God of Death, as he is a Faceless Man) as the "Red God" — that is, R'hllor, the Lord of Light. While this confusion has yet to be cleared up, a likely explanation lies in the fact that the "Many-faced God of Death" is a syncretic religion, which holds that every god or set of gods is just another facet of the god of death. Another possibility is that, just like he's imitating the speech style of a Lorathi, he also mentions the Red God as part of his cover identity.