Tiamat

Tiamat is a Deity widely worshipped by Dragonborn in The Old World. Along with her twin brother, Bahamut, she is one of two gods venerated in Draconic Dualism, the state Religion of Tymanther. She is depicted as a massive five-headed Dragon and is said to exemplify the pride, cunning, and ruthlessness which have allowed the Dragonborn to survive unconquered in a hostile world. Her holy symbol is a five-pointed spiral, often stylized as a set of Dragon claws arranged in a spiral pattern.

There is also evidence of Tiamat's presence in The New World, as her symbol has been discovered in the ruins of Anja's Folly and the Silver Dragon, Baerithyn Rex, asserts that the Draconic Civil War was fought between her worshipers and those of Bahamut.