Band of Battlehammers
Shimmergloom is the nickname of the ancient shadow dragon Haerinvureem. He is a massive, magnificent and terrible shadow dragon who arose from the depths of the Underdark after the Battlehammer Dwarves of Mithral Hall delved far too deep in the expansion of their mithral mines. It is said his true lair and his hoard of unimaginable size reside on the Plane of Shadows.
In the past, Shimmergloom drove the dwarves of Mithral Hall from their ancestral home, forcing them to resettle in the Icewind Dale region, and supplanted them with his Duergar servants. Shimmergloom reigned over the hall for roughly one dwarven generation until Bruenor Battlehammer, the rightful heir to the throne of Mithral Hall, returned to the hall in his adulthood in order to reclaim it. Shimmergloom attempted to retain his hold on the hall through the efforts of his servants, most notably two shadow mastiffs, although he eventually had to confront the intruders himself. He was eventually “slain” by Bruenor after the dwarf strapped a barrel of flaming oil to his back and jumped onto the shadow dragon’s back. The ensuing inferno destroyed Shimmergloom… or at least banished him back to his plane… Bruenor was unwittingly saved by carrying a famous friendly drow’s scimitar, Icingdeath, with him into battle. With the blade’s magical protection from fire, the dwarf was able to ride Shimmergloom’s burning corpse safely to the floor of the gorge.