Tell him that you could kill the Red Eclipse easily and then take control of their slave trade. Slash through the ranks until you encounter the leader of the group who will speak to you. Many more members of the Red Eclipse are on the ship waiting to do battle. Boarding the Ebon Hawk is the only way to advance the story line. The entire walkway to your craft is lined with these enemies so prepare yourself for a long battle. When you return to the ship there will be a group of thugs waiting for you known as the Red Eclipse.