UrSen was the Mystic monk and counterpart to skekLach the Collector. She died after skekLach was killed during the Second Battle of Stone-in-the-Wood.
Bio in the Age of Resistance canon
From "The Dark Crystal Bestiary Book", due to be release in October.
"Little is known about urSen the Monk, but that alone demonstrates the unassuming nature of his life shortly after the urRu exiled themselves to the Valley of the Mystics, making him the 5th exile Mystic (the others been urSan the Swimmer, urLii the Storyteller, urVa the Archer and urGoh the Wanderer). UrSen sought further seclusion moving to a cave in a region's outskirts. According to urSol the Chanter, it was possible that urSen had witnessed the premonition of his own death and spent the last hundred thrine of his life contemplating his impending fate".
UrSen died by proxy, when skekLach was killed by Deet, who redirected the Darkening attack unleashed by the Emperor's staff at the conclusion of the 2nd battle of Stone-in-the-Wood.
Other appearances
In the continuity established by Legends of the Dark Crystal, urSen survived to witness the Garthim War, and discretely guided the actions of Larh and Neffi.
An image of the unused design of urSen was finally made public for the upcoming The Dark Crystal Bestiary book, with his bio added.