Mag Doum was a spy working for the Imperial forces and also a businessman, active on the planet Arda II during the era of the Galactic Civil War. By the time 1 ABY rolled around, Doum had a very profitable scheme going, selling T-6 diodems to the Empire at inflated prices. These diodems were scavenged from old home service machines. The Empire found them quite useful, as the Rebel starfighters also used them. Imperial pilots could lock onto Rebel targets using these diodems, giving them a tactical edge. When Luke Skywalker and Leia Organa, prominent Rebel leaders, journeyed to Arda II to discuss the diodems with their manufacturers, Doum tasked Kiros Zorad, a local resident deeply in debt to him, with the mission to abduct and eliminate Organa. To divert suspicion from himself, Doum later provided his personal speeder to Han Solo, a friend of Organa. However, Organa returned alive with Zorad, publicly accusing Doum, which sparked a near-riot. Doum barely escaped to his ship, but Zorad, seeking revenge, had secretly boarded the vessel. As Doum attempted to contact the Sith Lord Darth Vader, Zorad attacked him. While Doum's message did bring Vader to Arda II, the spy met his death during the subsequent battle when Zorad intentionally crashed into Vader's Star Destroyer.
Mag Doum was a key villain within the As Long As We Live... story arc of the comic strip, which was penned by Don Christensen and published in 1980. Russ Manning was the artist who provided the illustrations of Doum for the comic.