Deity

A deity in the Realms is a being of great power that controls some aspect of mortal affairs, referred to as the god’s portfolio.

All deities of the Realms were either elevated to their positions by Ao or were approved by Ao to be worshipped in the Realms, in the case of immigrant deities. No divine power may found a permanent faith and power base without his approval, though there are cases of short-term semi-divine beings who gather faith from worshippers without being deities. The most noted example of this is the various fiendish cults that have arisen. In at least two cases, the worship of these cults have provided enough power or filled a niche that was not otherwise filled, and the fiends in question have become deities in their own right. Both Gargauth and the minotaur deity Baphomet became deities building on the power foundation of a fiendish cult.

The worship of mortals is also necessary for the continued existence and powers of a deity. The numbers and fervor of a god’s worshippers determine in large part the power of the deity. Deities without worshippers or who are fading in popularity fade in power, and in extreme cases can even die from neglect.

Native Deities
The native deities of Faerûn are those whose worship arose during the creation of Abeir-Toril, or shortly after, and who are only worshipped here. In general, the native deities are worshipped by the native races of Abeir-Toril, those that arose from the primordial chaos at Ao’s founding of this world. Humans, dragons, lizardfolk, nagas, yuan-ti, locathah, doppelgangers, and the fey races are the most common worshippers of native deities.

Immigrant Deities
Humans, elves, and other creatures have made their way onto the face of Abeir-Toril over the millennia. Many of them have brought their own divine patrons with them. Those gods who serve portfolios where no native Faerûnian power exists seem to almost automatically achieve divine status in the Realms. Those whose portfolios conflict with an existing deity are either absorbed into the existing deity or may contest for the power of their worshippers. In the last case, it may be a ‘winner take all’ type of event, or the loser may accept a smaller portfolio and a subservient position within the pantheon.

The gods of the dwarves, elves, and illithids, halflings, and gnomes followed their respective peoples into Abeir-Toril. Later, the gods of the orcs and other goblinoid races did the same, following and supporting their worshippers.

Dead Deities
Deities can also die. Conflict with other deities, conflict with great mortal heroes, and neglect are the most common causes of a divine demise, though it’s also possible for a god to lapse into apathy, drift into sleep on the astral plane, and eventually perish. Ulutiu is a prime example of this last possibility.

Pantheons
A pantheon is a grouping of deities, often with overlapping worshippers. All of them are based on races or cultures, usually with strong geographic ties.

Faerûnian
The Faerûnian pantheon is the primary human pantheon that is venerated across Faerûn. It is composed primarily of native deities, and is the result of millennia of cultural blending of various other pantheons to bring out a moderately unified whole. There are remnants of other human pantheons that have been combined into a single pantheon as their source cultures have blended, merged, and conquered one another.

The Talfiric pantheon was worshipped in contemporary of Netheril, and is the source of at least Garagos, who lost in the clash with Tempus and was reduced to demigod status. The Netherese pantheon itself claimed the worship of the lower and middle classes of Netheril, and the survivors of the Netherese pantheon are perhaps the most numerous of the survivors of the gods of history, boasting Jannath (now known as Chauntea, Targus (now known as Garagos), Mystryl (whose power now lives on in Mystra), Shar, Talos, and Tyche (who split during the Dawn Cataclysm and became Tymora and Beshaba).

The Jhaamdathan pantheon was worshipped in what is now the Vilhon Reach and the Dragon Coast. The Coramshite pantheon was based in what is now Calimshan. The Untheric pantheon once maintained a separate status similar to the Mulhorandi pantheon (covering Unther, Chessenta, and the Raurin desert), but collapsed during the Time of Troubles, and is now a part of the main Faerûnian pantheon. Only two of the old Untheric deities have survived, Assuran (now called Hoar), and Tiamat; the others died during or before the Time of Troubles.

Mulhorandi
The Mulhorandi pantheon is a group of immigrant deities that followed their people when the wizards of the ancient Imaskari Empire brought legions of slaves through gates from another world. At first, the gods could not reach their worshippers directly, and were compelled to create manifestations to contain a portion of their divine power.

Those manifestations walked among their mortal followers, guiding, protecting, or dominating according to their natures until the Time of Troubles. After that perilous time, the ancient barriers that had separated them from their true divine essences were dissolved, and the Mulhorandi pantheon left their manifestations behind as powerful mortal servants and took up their natural divine positions.

The worship of the Mulhorandi pantheon at one time covered Mulhorand, Thay, Semphar, and what is now the Raurin desert. Now they’re struggling to hold onto Mulhorand itself, with their worship waning in Thay and Semphar. They’re also striving to convert the followers of the collapsed Untheric pantheon. Only time will tell if they succeed or fade away.

Chultan
The people of the Chultan peninsula all tend to worship Ubtao.

Drow
The Drow worship the Dark Seldarine, deities that were cast out of the Seldarine after the failed invasion of Arvandor by the Anti-Seldarine. This original trio of gods was joined by four more as time passed.

Elven
The elves tend to worship the Seldarine. Gods that they brought with them when they originally came to Faerûn.

Other Monstrous Faiths
Monsters don't tend to want to worship the deities of the more civilised races. A lot of monsters have their own gods whose portfolios consist of dominion over the creatures that worship them such as the kobold god, Kurtulmak. Some species however, have a whole pantheon of gods such as the Yuan-Ti pantheon (that has actually been secretly subsumed by Set

Fiend Worship
Some fiends have gained enough mortal followers on Faerûn to achieve a divine portfolio. Most of these are demons from the abyss such as Yeenoghu and Baphomet, while devils such as Gargauth have also managed to do so.