Agatheron's Points of Light
The Tiefling empire of Bael Turath was one of two continent-spanning empires that predated the Empire of Nerath by perhaps a thousand years or more. Precise dating is uncertain. What is known is that Bael Turath was founded by humans, and expanded so rapidly that control was beginning to slip from their grasp. Fearing this loss of power and control, the noble houses of the Empire made infernal pacts with the Nine Hells, specifically Asmodeus himself. This ritual pact transformed the nobles, and subsequently the empire into the race of Tieflings.
Yet for all the efforts, Bael Turath would eventually crumble. Not at the hands of another power, but in a centuries-long struggle against one. The Dragonborn empire of Arkhosia rivalled Bael Turath in might and influence. For many centuries they would vie for power and territory. Eventually, both empires would collapse under the weight of their own struggle, and both the Dragonborn and the Tieflings would be left as wandering peoples in the ashes of their two empires.