Isengrim was the leader of the "Vrihedd" brigade during the Battle of Brenna. He held the rank of Colonel. As a condition of the Treaty of Cintra, thirty-two elven commanders that fought under Nilfgaardian banner were captured and surrendered to the Northern Kingdoms, including Isengrim. He managed to escape and fled to the foot of the Elskerdeg Pass, where he met with Sigismund Dijkstra and Boreas Mun, both fugitives for their own reasons. The three of them formed an unlikely travelling party, heading East, towards Zerrikania or even Haakland, presumably leaving the territories of the Nilfgaard Empire and the Northern Kingdoms for good.