Nartheling laired in Umbergoth, near the border between Aglarond and Thay, served by many lesser monsters like griffins, asperii, and other winged beasts. He also had a retinue of beholders and wyverns.
In 1372 DR, Nartheling was courted by the Cult of the Dragon necromancer Winn Kardzen to become a dracolich but his designated phylactery, a horn of the fallen Shargrailar, became lost in the Yuirwood.
During the Rage of Dragons of 1373 DR, Nartheling started to attack and kill the beholders on sight. His servant Lestch'cymatium called many more beholders to help and nearly started a full-scale war, alarming the populations of both Aglarond and and Thay. After the Rage, Nartheling ceased hostilities immediately and Lestch'cymatium returned to his service. Afterward, Nartheling found a series of portals in the caves of Umbergoth and started to explore them.