The Citadel of Black Ash was a temple to Gilgeam, god-king of Unther, located in the eastern Smoking Mountains near the Black Ash Plain at the apex of a 3-mile-long (5 km) valley filled with waist-deep silty ash, giant scorpions, and other hazards.
A millennium before Enlil founded the nation of Unther, a clan of dwarven explorers investigating lava tubes deep in the Smoking Mountains inadvertently awakened a great brown wyrm named Vulpomyscan. The dragon enslaved the entire clan and put them to work mining a hoard of gems and building a lair worthy of his cunning and might.
When the expanding Untheric empire eventually encroached upon Vulpomyscan's claimed territory, clashes broke out and the dragon terrorized and plundered the human settlements. Soon after, the god Marduk the Justice Bringer led an army to battle the dragon and defeated him in a titanic battle with heavy loses on both sides. After looting the Citadel, they abandoned it, and it remained forgotten until Gilgeam, son of Enlil, rediscovered it almost a thousand years later and claimed it for himself.