Pirate hunter

Pirate Hunters were groups of sailors who, during the Golden Age of Piracy, tracked down and killed notorious pirates throughout the Caribbean, at the behest of various local governments and empires.

Using a variety of ships, ranging from schooners to Men O' War, pirate hunters would follow and attack their targets after the pirate had become notorious enough. Easily recognizable by their crimson sails and black-and-red hulls, hunters wore brown outfits with red accents, and were often converted pirates. Benjamin Hornigold was one such pirate hunter, working to eliminate his former allies after he joined the Templar Order in 1718. His two lieutenants, Josiah Burgess and John Cockram, joined him in his task, and succeeded in killing the pirate captain Howell in Principe the following year.

During his career as a pirate, Edward Kenway would occasionally attract the attention of the pirate hunters, even going so far as to purposely lure a group of hunters to his location while completing a mission on the behalf of the Dutch merchant Milo van der Graaff.

Reference

 * Assassin's Creed IV: Black Flag