Swain was a sworn brother of the Black Company mentioned during the events of "Bone Eaters". When Croaker the (physician and Annalist) was treating the young soldier named Twiller for the clap, he surmised Twiller probably got from a refugee woman whom Swain bedded. And Swain probably got it from one of Twiller's girls, back when Twiller had it last.
Swain is not mentioned again in the available Annals. But, like all other brothers mentioned prior to the Battle of the Barrowland, he is presumed deceased since he was not among the 10 Company survivors of that battle.