Tiamat (Forgotten Realms), The Dragon Queen
Domain: Tyranny, Vengeance
The eternal foe of Bahamut. Tiamat, revered as the mother of all chromatic dragons, was once known to the Untheric people as the Nemesis of the Gods and worked to overthrow the other deities of their pantheons. She now lurks and plots under the rule of the mighty god Bane, operating from her various lairs in the desolate realm of Banehold.
Published in Forgotten Realms Campaign Guide, page(s) 80.