Tiamat

Tiamat

She was originally a mortal blue dragon called Thalatte. As a very powerful sorcerer, she gained lot of power during the Civil war and ascended to godhood. She argued with the new God Bahamut who, depending on the source, was either her brother or husband. Their ways parted and she woved on having revenge on him, after which she took a new name: Tiamat.
Her aspects began to blend together with the minor goddess Zirnitra and nowadays they are considered the same.

Church/Cult

The Draconic Pantheon