Moss was a faithful palace guard who was taken from Del to the Shadowlands sometime during the Shadowlands invasion. During the time he spent in the Shadowlands, he joined the Resistance. At some point, he was captured by the Shadow Lord's forces and used as a test for the Conversion Project. Moss was sent back to Del, though he was an imperfect specimen, to attempt to assassinate the king. Due to the carrier worm in his head, Moss could not walk without crutches. Under the control of the carrier worm, Moss attempted to choke Lief when the young king bent down to speak with him. Three guards came to Lief's aid, and it took all of their combined strength to overcome the man's choking grip. As Moss was being moved away, an unknown person in the crowd knifed him in the back, killing him.
When travelling with Lief, Barda, Jasmine, and Emlis through the tunnels under the Dead Plain in the Shadowlands, Claw, Brianne, and Gers found one of their Resistance hideouts had been ransacked. The people who had been living there, including Moss and several other Resistance members, had either been killed or taken prisoner. The three Shadowlands Resistance members expressed grief for the loss of Moss and several more of their allies and friends.