The Ashen Covenant Rises
Arkhosia was the great empire of Dragons.
Metallic dragons were the political, religious, and military leaders and dragonborn were the general populace. They were a nomadic people who made few permanent settlements. The ones that they created were often huge monuments – pyramids and temples to Bahamut were common and the various dragonborn clans would make pilgrimages to them on their trade routes.
Due to their hearty bodies and great strength, many dragonborn were taken as slaves by b Bael-Turath during their travels. This injustice created a great war between the devils and dragons that eventually led to the destruction of both civilizations. The dragons became isolationist afterwards, concerned only with their individual survival and the protection of their hoarded treasures. The dragonborn dispersed amongst all civilizations as wanderers and mercenaries. They felt that it was not their fate to rule over others and stay in one spot.
The brass desert, south of the Nentir Vale is a place where this is not the case. Vorumral rules over this place because it is the site of many Arkhosian ruins and artifacts. He sees is as his holy duty to keep it under draconic control.