Thunderhold: Castle of the Dwarven King

From publisher blurb: The Dwarves of Thunderhold originated at the Majestic Fastness, deep in the Majestic Mountains. They were forced from their ancestral home by the great dragon, Analegorn, and its three young some 400 years ago. The Dwarves journeyed north to the region of the Sunstone Caverns, rumored to possess a lode of mithral. There the dwarves found an army of gnolls who held the caverns and the adjacent castle.