Roronoa Zoro, also known as "Pirate Hunter" Zoro, is a main combatant of the Straw Hat Pirates, one of their two swordsmen, one of the Senior Officers of the Straw Hat Grand Fleet, and is publicly recognized as the right-hand man of his crew's captain Monkey D. Luffy.Formerly a bounty hunter, he is the second member of Luffy's crew and the first to join it, doing so in the Romance Dawn Arc.

Born in the East Blue, Zoro is the son of Tera and Roronoa Arashi, the grandson of Shimotsuki Furiko and Roronoa Pinzoro, and the grandnephew of Shimotsuki Ushimaru, making him a matrilineal descendant of both the Shimotsuki Family of Wano Country and the legendary samurai, Shimotsuki Ryuma.[3][11] As a master of Three Sword Style, a swordsmanship style which he created during his childhood training in Shimotsuki Village, Zoro is one of the most powerful combatants of the Straw Hats, alongside Luffy and Sanji, who are referred to as the "Monster Trio".[23][24] His dream is to become the greatest swordsman in the world, in order to honor a promise he made to his fallen childhood friend Kuina.[25] 

He gained his first bounty of 60,000,000 after the Arabasta Arc. It later increased to 120,000,000 after the Enies Lobby incident, then again to 320,000,000 after the Dressrosa Arc.[17] Following the Raid on Onigashima, his bounty was increased to 1,111,000,000.[16]