Very random poll indeed, but Arthur would win, without a doubt. A gunslinger with six shooters, rifles, and double-barreled shotguns would beat an archer anyday.

Arthur can also use a bow and has explosive arrows

Arthur has guns.

Thanks to his incomprehensible pain tolerance and infinite health, arthur would win by far

^ As Arthur, I could pull an Andrew Jackson and get shot in the chest and still win the duel.

Bro thinks he is funny

Arthur Morgan

Marthur Organ

Simple: Arthur has a revolver, automatic pistols, semi-automatic shotgun, 14-shot rifles, and the Dead Eye

Robin Hood hides in a tree and waits for Arthur to come along so he can shoot him, Arthur is struck in his shoulder, then whips around and using dead-eye Vietnam's the fuck out of the tree with a fire bottle and Robin Hood gets roasted alive.