William Crest

William Crest was a dangerous pirate, who along with his fellow pirate Joseph Reed made a fortune attacking and raiding ships in the Atlantic Ocean during the mid-18th century. Crest captained a Man O' War called the Cauldron. The Cauldron and it's sister ship, Reed's Pilgrim were eventually sunk by the Templar Shay Cormac's ship, the Morrigan.

Reference

 * Assassin's Creed: Rogue