Masvirik

Masvirik, the Cold Sun is an Overlord from the Age of Demons with dominion over reptilian creatures, that is mostly forgotten by those outside of the lizardfolk tribes of the Masvirik'Uala.
In the Age of Demons, Masvirik dominated the lizardfolk and other scaly creatures of the region from his throne in the city of Haka’torvhak. The sacrifice of the couatl to form the Silver Flame bound him and freed the lizardfolk from his will. Black dragons soon were dispatched to watch over the obsidian city of Haka'torvhak, said to contain fiends trapped since the Age of Demons.
Three thousand years after Rhashaak's watch first began, Masvirik escaped his bonds and Eberron dragonshards housing the scattered shards of his essence flared, and awakened ancient dreams in the lizardfolk. This along with the return of the dragonborn descendants of the legions of the original members of the Light of Siberys, long-since spread out across the lands of eastern Khorvaire under dreams of conquest, helped seal Masvirik within its prison.
Masvirik has some followers among the Lords of Dust, but maintains no prakhutu on the Bleak Council.