Dumas Poe was a descendant of Kattak Po, a Tibetan monk who supposedly invented firearms. Feeling remorseful over all the death guns caused, Kattak made it his life's mission to stop their spread and prevent gun-inflicted deaths. His descendants followed in his footsteps. They became known as Gunmasters because of their knowledge of firearms and their ability to use them with superhuman accuracy.
Like his predecessors Dumas used his skills, which were so good that not only could he shot guns out of the hands for foes, he could even shoot bullets out of the air, fight for justice on behalf of the victims of gun violence.
He was assisted by the robed Circle of Elders, the spirits of previous Gunmasters who appeared in his room whenever he asked for their aid and who could see where he needed to go next, and who also saw to it had he had enough riches to travel the world to do what was needed.