He reluctantly agreed not to interfere with Ravidel, when the Battlemage threatened to destroy the city. He hid the long-daggers after discovering how to use them to destroy the Golgothian Sylex, but later was banished to the sand seas of Golthonor by Ravidel, where he worked on the rust spell to destroy the Sylex. He was the father of Gwendolynn Mor, who married Adam Carthalion and thus made Grenfell Mor the grandfather of Jared Carthalion. He tried to kill Jared with Valthus, his leviathan, when the Wayfarer came to Telemar City with Kristina of the Woods, but failed.
Grenfell Mor may have been a descendant of Gydolien Mor, though this is uncertain.