The Sister Mercy is a ghost ship found sailing just north of Scalawag Point in Howling Fjord. The crew was killed about a month prior to the adventurers' arrival, most likely by Sorlof, who is now holding treasure taken from the pirates. Cursed by these once Northsea Freebooters will not rest until they reclaim what is rightfully theirs.
Below deck the gunners have mutinied leaving the rest of the crew forced to deal with them and Sorlof. This is where the adventurer helps, by getting the blasting powder from the gunners to use on The Big Gun to kill the giant and bring back the treasure to the captain so that they might finally rest in peace.
- To board the ship (without flight), one has to swim to the tiny island where Juniper is standing. The ship will arrive roughly every five minutes.
- Before the boat arrives, you will notice there is no way to board the ship. That is because when the ship arrives, a strange ladder will somehow "magically" appear out of nowhere.
- The boat is the only of its kind to use the current model of a pirate battleship, making this boat one of a kind.
- This boat is also unique in the fact it's the only boat that goes around in circles with one dock (like the zeppelin that leaves Westguard Keep).
- If you're a death knight you can use , get in front of the ship, when it moves forward you will be in a glitched ship, jump and you'll be in the ship.
- This ship is a possible reference to the Black Pearl from Pirates of the Caribbean: The Curse of the Black Pearl.
- The ship's name might be a reference to the band The Sisters of Mercy.