Tso Lien was a sworn brother of the Black Company, and was one of Sleepy's officers. He came from a province in Hsien where styles of speech were considered important. Willow Swan inwardly mocks him for his flowery speech. Croaker considered him to be "another of those fiercely competent professional officers who had wanted to shed the feudal chains of Hsien in hopes of making his fortune".
Prior to the Battle at the Shadowlander cemetery, Sleepy ordered Tso Lien to bring a recon team to the Grove of Doom. This was to find out if Mogaba had set a trap, as well as to report on the remnants of the Stranglers (that were massacred and beheaded there by Aridatha Singh's City Battalions). Tso Lien was last reported alive, but he may have been killed in the especially violent battle beside the nearby Shadowlander cemetery.