Tiamat

Tiamat is the queen of all evil dragons, and was once the consort of Bahamut.

She was directly responsible for the creation of the Abjurewall, and also the death and resurrection of Lazazul, the Shadow Dragon. Her only direct child by Bahamut is the dragon god Parttich, whose company she detests. She opposes Bahamut only out of principle, and still longs for a reunion of the dragon races.