Monkey D. Luffy’s path to mastering Haki in ‘One Piece’ is a big deal for anyone following his wild adventure. As the Straw Hat captain, he’s had to level up his skills to take on tougher ...

when Luffy began his two-year training on the island of Ruskaina. Since then, Conqueror's Haki has been prevalent in One Piece and every now and then, a new user of Conqueror's Haki pops up.