Glustrod was the youngest son of Almighty Euz. Unlike his brothers, Kanedias, Juvens, and Bedesh, he was granted no gift from his father apart from his blessing. He harboured a bitter resentment toward his brothers, and toward Juvens especially. He allied with Demons on the Other Side, and made war on the Old Empire, Juvens' greatest achievement.
History
After Euz vanquished the Demons and closed the gates to the Other Side, he granted a gift to his three eldest sons – the three pure Disciplines of Magic. To Glustrod should have gone the gift of communing with the Other Side, but such things were forbidden by the First Law, so Euz gave nothing to his youngest son but his blessing.
Glustrod begged all three brothers for a share of their secrets, but all three refused him. He looked upon what Juvens had achieved in the Old Empire, and was bitter beyond words. So Glustrod studied forbidden sciences and began to hear voices from the Other Side. The voices told Glustrod to break the Second Law in order to gain power, and where to dig for the Seed. Glustrod became an Eater and gathered an army of Devil-Bloods, people distantly descended from Demons. Through treachery, he entered the capital of the Old Empire, Aulcus, while Juvens was away, and gave the city to his army to rape, destroy and slaughter for one day.
When Juvens saw what Glustrod had done, he sought the aid of his brothers. Only Bedesh would come; Kanedias was too consumed by his work in the House of the Maker. Juvens and Bedesh raised an army without him, and they fought a terrible war against their brother. In the end, they were victorious, and Glustrod was besieged in Aulcus. In desperation, Glustrod tried to use the Seed to open the gates to the Other Side. But in his haste, he made some small mistake, and the great power was released without form or reason. Glustrod destroyed himself and the Old Empire, with Aulcus left a wasteland, forever poisoned. In the wasteland, nothing grows or decays.
When Juvens' army entered the ruined city, they found the Seed. Although Juvens suffered no ill from the stone, an entire legion of soldiers was consumed by an unknown wasting disease, and soon died.
Recent Events
The story of Glustrod is mentioned infrequently throughout the series, most notably Malacus Quai tells the full tale of the rise and fall of the Old Empire on the journey to the Edge of the World.
In the Great Northern Library, Bayaz possesses a large book with a scarred and battered-looking black cover written by Glustrod. Yoru Sulfur brings Glustrod's book to Bayaz in Adua. During the Battle of Adua, Bayaz uses the Seed against Khalul's army of Eaters by combining the knowledge of Glustrod with the investigations of Kanedias. The result is much the same as Aulcus, albeit on a smaller scale; "a touch less careless slaughter, and ruined a smaller part of a smaller city".