Wilderlands: The Rise of Tharizdun
The dwarves of Thunderhold were driven out of their ancestral home in the Majestic Fastness, deep in the Majestic Mountains, 400 years ago by the dragon Analegorn and his young. The dwarves journeyed north to the Sunstone Caverns, rumored to possess a load of mithril. There, they found and defeated an army of gnolls who held the caverns and an adjacent castle and founded Thunderhold. The dwarven King maintains close ties and trade with the City State.