|Age||Possibly around the age of 20|
|First Appearance||"Secrets" (Mentioned)|
|Last Appearance||"Nebraska" (Corpse)|
All that is known of Duncan's past, is that he knew the Greene family before the outbreak.
Duncan was killed sometime after the outbreak. Before his initial reanimation, Otis placed him inside the barn.
Toward the end of the episode, Shane unlocks the door of the barn and the group of Atlanta Survivors shoots everyone that was inside. Duncan was killed along with all the other walkers exiting the barn.
It is unknown if Duncan was bitten and infected by a walker, or died of another cause. Being infected, Hershel orders Otis to place him inside the barn, where he reanimates as a walker.
- Atlanta Survivors
After Shane forces the barn door to open, the walkers exit the barn and are gunned down by the group including Duncan; it is unknown who actually shot and killed him.