Duncan was a member of Interplanetary Expeditions, assigned to the Excalibur. He was the third in command of the IPX expedition on the Excalibur, behind Maximilian Eilerson and Sogayu.
In 2267, he was on an expedition to a dead planet where its inhabitants would kill each other when nightfall came.[1] Duncan described a shape attacking Sogayu out of the shadows, but could not explain exactly how she died even though he was in front of her when she perished.
It is likely that the virus created by the Technomage on this planet caused him to kill Sogayu since he was with her when she died.