Ghostly Crew is a Field Order Reward found exclusively on the map Mutiny. When activated, the player is escorted by two ethereal ghost pirates, who kill any enemy they see.
One of the pirates utilizes akimbo flintlock pistols, while the other has a hook that acts as a melee weapon.
The ghosts themselves do not have a lot of health, so they can be particularly easy to kill if one reacts quick enough. However, considering the two ghosts escort the enemy player, a single player could easily be picked off by the other pirate or the enemy player that the ghosts follow. It is best to tackle the pirates as a group, as there's essentially 3 enemies to take out. As well, due to their close range weaponry, it is easier to just pick them off using a Light Machine Gun or a Sniper Rifle.