Duke

 was the highest feudal rank after King. The domain of a was a Domain of::Duchy.

See Noble Titles for more information on noble titles and feudal hierarchy.

Little is known about the dukes, but apparently most of the lands where Brianna Barter had her adventures were in some specific duchy. The duke apparently had soldiers or guard who had custody of Red Jack at one point. He was apparently also unwilling or unable to intervene in Marquis Byron Avengene's attacks on the Church of Mortaebius. That implied that the duke was, at least in theory, in charge of the matters in this part of the kingdom.

In 725 the Duke had a program to grant relief from some criminal punishment in exchange for risky service: the Duke's Clemency.