Tiamat

Tiamat is the dragon idol of greed. She once served Bane, The Conqueror during the Sundering. Tiamat was banished to the 9 hells long ago, along with many other idols and evil beings. She now reluctantly serves Asmodeus, The Prince of Pleasure, and seeks new ways to return to the material plane.
She has a strong following among the chromatic dragons, and small sects of dragonborn.