Deem was a Capellan warrior loyal to Maab. He had previously met Federation Doctor Leonard McCoy during his visit to Capella IV sometime prior to 2267.

After Maab became Teer of the Ten Tribes, Deem participated in the group searching for the USS Enterprise landing party. After Kras holed himself up with a phaser near a large rock, Maab declared that their deal had been forfeited and ordered Deem to neutralized the Klingon with his kleegat. Deem was vaporized by Kras' phaser before he could remove his weapon from his holster. (TOS: "Friday's Child")

Deem was played by an unknown actor. Closed-captioning gives his name as "Naam" or "Liam".