When the ghost has taken a certain amount of damage it will disappear and summon in more ghosts: Haknir's Crew. Haknir will disappear and leave you to fight his crew. Take them out with a fervor. There are a fair number of them, close to a dozen.
After you defeat the crew, Haknir will appear again, close to where his skeleton is. Engage him and keep on the move to avoid getting cornered. He will continue to fight you until you lower his health to half or less. He will disappear again.
This will cause Thalin Ebonhand and Garuk Windrime to appear in the fray. You will need to fight and defeat them. Next, more of Haknir's Crew will appear. Start eliminating them to keep the fight moving forward. This will get Haknir to reappear.
- Kill the pirates
- Use the Deathbrand Treasure Map to find the Treasure
- Explore Gyldenhul Barrow
- Defeat Haknir Death-Brand