Tiamat

Tiamat is the five-headed dragon goddess of death, darkness, greed, lust, and evil. She is the younger sister of Bahamut, who is her main rival.

History

Tiamat was born jealous of her brother, and constantly sought to thwart his projects. When he created the first intelligent beings, the dragons, it was Tiamat who managed to corrupt many of them with the concept of greed. After her corruption of the dragons, she led an all-out assault on Bahamut and his dragons in the first celestial dragon war. She was beaten and as punishment, banished to Baator, the Nine Hells. After her banishment, she began to expand her influence throughout other planes, including the Abyss and Gehenna, breeding with demons and devils, spawning the various evil gods of Elendar.