Dungeon of the Ruins

The Dungeon of the Ruins was an abandoned dwarf hold located about halfway between Mithral Hall and Nesmé.

History
Originally a dwarven hold called Andalbruin, the site was transformed into a human village when the Selskar Order, a group of Netherese arcanists, occupied the ruins of the hold in −626 DR and set up a magic school named Selskartur ("Tower of the Star" in Loross).

Less than forty years later, as the village looked to expand into a realm of its own, the troll warlord Harska Thaug attempted to attack Rilithar but Selskartur was caught in-between the troll's forces and the elves. Troll magic-users defended Harska's army against the arcane might of the Selskar Order and appeared to have the upper hand despite taking tremendous casualties. Ilviroon, the leader of the Selskar Order, opened a gate and summoned Bazim-Gorag, whom he charged with burning the trolls to death. Bazim-Gorag did as he was commanded and drove the trolls into the Spine of the World. When Ilviroon dallied in compensating the slaad lord for his services, Bazim-Gorag turned on his summoners and killed many Selskar arcanists. Ilviroon trapped and bound Bazim-Gorag in some dwarven vaults beneath Selskartur and left him there, beginning an effort to rebuild what had been destroyed.

Harska and his trolls returned the following winter, however, and though still weak from the last attack, the Selskar Order was wiped out. Unfortunately, Ilviroon was the only person who knew how to release Bazim-Gorag from his binding. The slaad was trapped with no hope of rescue for nearly two thousand years.

Over that time, Selskartur became known as the Dungeon of the Ruins and in 1356 DR adventurers calling themselves the Company of the Riven Orb ventured far enough into the dungeon to meet their ends at the eyes of a beholder just outside Bazim-Gorag's vault. With the path to him almost completely clear of obstructions, the slaad managed to remotely influence many evil individuals to come serve him. These individuals became a cult, calling themselves the Acolytes of the Hidden Flame, and came to inhabit the dungeon, doing all they could to enact Bazim-Gorag's will. In 1373 DR, a durzagon cultist discovered a method to free his master but his plans were foiled by adventurers.

Rumors & Legends
The local barbarians avoided the subterranean tunnels because of tales of "strange froglike humanoids (possibly slaad) dancing around bonfires in the ruins."