Mosley the Snake is the chief of the bandits who kidnapped Eileen Bensley during the quest A Daughter Ransomed.
The Warden-Commander can persuade him to hand over Eileen before they give him the money. If successful, Mosley will ask for the ransom. The Warden-Commander can then either give Mosely the ransom, or refuse. If the Warden-Commander refuses, a fight will ensue and Mosely and his thugs must be killed.