Duncan was a lurker, residing in Downbelow onboard Babylon 5. He sold trinkets for a meager living, and was a friend of occasional visitor Marcus Cole.
In 2260, Duncan, seeing no foreseeable prospects for himself, agreed to become host to a Vindrizi. He was amazed by the wondrous sights seen by his Vindrizi.
Duncan's Vindrizi exited his body to prove to Marcus and Stephen Franklin that its race meant no harm. He was unable to take on another one, but left Babylon 5 to see the universe for himself.