The Church of Bahamut has existed in several guises over the millennia since the Time of Dragons. It is strictly regimented but undergoing a more recent transition from exclusively draconic membership to include humanoids as well.
The Church of Bahamut first began as the Cult of Xymor, which began as a cult of personality around the first dragon known to have achieved the transformation into the Platinum Dragon. Xymor led the charge against the evil dragons and slew the behemoth Nagamat. His followers and many other metallic dragons began to revere Xymor as a god, and this continued for many millennia.
Ultimately the Cult of Xymor declined, along with the worship of many other dragon gods, whose followers led the draconic races into near extinct in wars of ideological genocide. The faithful of Bahamut and Tiamat in particular were abandoned and eventually faded into history. Dragons came to the conclusion that Bahamut and Tiamat are the epitomy of their kind, but the pride of dragons mean they regard themselves as supreme and therefore worship no other master.
Bahamut appeared in many aspects over the millennia, always battling Tiamat and her forces of evil, but it wasnt until the arrival of the mulan from another world that the Church of Bahamut was reborn in the guise of the Church of Marduk. Marduk was the godking of justice and protection in the land of Unther, his followers were almost exclusively mulan humans, and he himself was of humanoid form (some in the Church of Bahamut today believe he was a dragon shapechanged into human form, or perhaps a half dragon).
Marduk was a popular deity and his church was a large organisation with a rigid hierarchy that lasted for over 1000 years but never spread beyond the political boundaries of Unther (although Unther itself claimed lands now known as Thay and Aglarond at this time). Marduk was slain in the Orcgate Wars (-1076 DR to -1069 DR) and his Church collapsed overnight. It is known that a few diehard supporters seeking vengeance for the death of their godking pursued the grey orcs as they fled west of the Netarand in a conflict now known as the Scattering of the Tusks.
Again the Church of Bahamut was lost to history, but in recent years dragons and humanoids alike have been revering Bahamut the Platinum Dragon once more, and some say the Platinum Dragon himself has been seen in the form of an old man accompanied by 7 canaries who battles giants and evil dragons alike. These sightings and roaming faithful are most often encountered in the Bloodstone Lands.
Members: 50+ metallic dragons, 200+ humanoids
Leader: The King of Justice
Secrecy: Low, the Church of Bahamut does not normally keep its activities secret unless operating in areas where the forces of Tiamat are strong.
Symbol: A five pointed star above a milky nebula (the symbol of the Church of Marduk was a reptilian eye over a square of gold)
Despite the disparate nature of the Church of Bahamut, with a large proportion of the senior faithful being metallic dragons whose lairs are spread out across large areas of Faerun, the church itself has a strictly regimented hierarchy based upon the natural hierarchy of metallic dragons and mixed with a more traditional human church hierarchy.
The Church of Bahamut is ultimately led by the King of Justice who is the oldest, wisest, and most powerful gold dragon (as appointed by his peers) and Bahamut’s mortal representative on Toril. His rule is only superseded in the event that an aspect of Bahamut appears and then the King of Justice must obey the orders of the aspect.
Draconic members of the church are regimented according to age and type, with the order being gold, silver, bronze, brass, copper for types. Humanoid members are given a variety of titles that are equivalent to certain age categories but always below a true dragon; Master of the Winds (Ancient), Transcendent Justice (Old), Hand of Justice (Mature), Honoured Talon (Adult), Platinum Knight (Juvenile), Noble Aspirant (Wymrling). There are a number of draconic humanoid members in the Church of Bahamut (half dragons, dragonborn, etc), these individuals are treated as dragons based upon their age, or as humanoids based upon an appointed title.
Dogma / Motivation / Goals
Bahamut is an Archetype, the epitome of good dragons, he does not require worship like deities, however, his followers do not necessarily understand or care about the distinction and have constructed a church about their own beliefs and the legends of Bahamut.
The Church of Bahamut preaches that Bahamut delivers enlightened justice to all. Laws for the sake of it, or laws that protect the greedy, and the immoral serve none but the forces of evil. The Church of Bahamut delivers true justice, ensuring that the evil are punished and the good are protected, sometimes in spite of the letter of the law. In matters of law the followers of Bahamut do not deliver vengeance or rash punishments, but rather they deliberate carefully on the matter and ensure the activities of evil are truly punished.
Dogma: The faithful of Bahamut are charged with fighting evil and injustice wherever it may exist. The Church of Bahamut obeys the law, but only when the law serves true justice, where it does not then the followers of the Platinum Dragon are to ensure justice is served (without committing evil acts themselves).
Bahamut is also incredibly compassionate, and while he encourages people to fight their own battles, those who cannot must be protected. The faithful of Bahamut must protect the weak, the young, the elderly, and aid those fighting against greater odds.
Most of all however, the Church of Bahamut is charged with fighting against the forces of Tiamat wherever they find them, for she represents everything evil in dragonkind and encourages that evil in everything else.