Undermountain

Undermountain was a multi-tiered dungeon, comprised of several inter-connected chambers and lairs located deep beneath the city of Waterdeep and its namesake mountain. Originally home to the dwarves of Clan Melairkyn, the Underhalls were home to a grand dwarfhold before they were taken over by the "Mad Mage" Halaster Blackcloak and his seven apprentices.