Maerglor

Maerglor was an evil mage who lived in Elturel in the Western Heartlands some time before 1357 DR.

Maerglor bought the Shadowtome from a band of hobgoblins who'd killed the mage Azkhazan in the mountains north of Iriaebor, giving them food, weapons, and quality armor in exchange. Later, Maerglor sold the book to Elminster.