Gotha

Gotha is a dracolich who was formerly a dragon and was transformed by Talos.

Background
Talos, the god of destruction, approached Gotha to make a proposal. Talos vowed to keep Gotha from death indefinitely provided Gotha would perform an unnamed task of destruction at some point in the future, at Talos's request. Gotha feared the effects of age and his eventual death more than anything else, and subsequently agreed. Talos instructed him to fly to the north of Faerûn to an ice cave, where an avalanche trapped him for a total of 237 years, keeping him alive and in constant pain, and transforming him into a dracolich.