In the anime and manga series "One Piece," the protagonist Monkey D. Luffy does not typically use a sword as his primary weapon. Luffy is a rubber-powered pirate who possesses the ability to stretch and manipulate his body due to eating a Devil Fruit. Instead of relying on swords, Luffy mainly fights using his extraordinary physical strength and his unique fighting style, which incorporates hand-to-hand combat techniques and his rubber-based abilities.

It's important to note that while Luffy primarily relies on his fists and body in combat, other characters in the series, such as Roronoa Zoro, are known for their proficiency in swordsmanship and wield swords as their main weapons.