Persuasion

A two-handed warhammer (also known as a maul) with a leather wrapped shaft, and a piece of bone for the pommel. The head of the hammer appears to be bones and a skull, or just the skull. Possibly that of a large bull, or bronto.

Acquisition
Found during the quest Inside Job when traveled to a map area known as 'Outside of Kirkwall', and after defeating basic human mercenary type enemies. It's in a chest along with other loot/weapons/armor.