Doorn was a Human male living on the planet Coruscant. He worked as a police officer for the Coruscant Security Force and was able to achieve the rank of lieutenant before the Great Galactic War between the Galactic Republic and Sith Empire. During the Cold War period that followed the war, Doorn was posted to the Black Sun territory. The assignment was difficult, with constant street warfare against the Black Sun crime syndicate. Like many veteran cops, Doorn became extremely cynical, frustrated, and burned out. At one point he was assigned the task of securing plans for Coruscant's secret tunnels. Working with Agent Fieler Dan of the Republic Strategic Information Service, Doorn tracked the plans to Coruscant's Justicar territory. When Dan failed to contact Doorn, he sent a Republic indi