Harrow is a member of the Mythic Dawn who oversees new member inductions. He is also the Warden to the Shrine of Dagon, located within the Lake Arrius Caverns.
During the main quest "Dagon Shrine", he will ask that the Hero to hand over all of their equipment and gold in order to be allowed into the Shrine. However, the gold can be looted or pickpocketed off of him the mission. He will give the Hero a Mythic Dawn Robe to wear as a temporary replacement.