As of my knowledge cutoff in September 2021, Luffy, the main protagonist of the One Piece series, does not regularly use or possess a sword. Luffy's primary fighting style revolves around his powerful and versatile rubber-based abilities as a result of consuming the Gum-Gum Fruit.

However, there have been instances in the series where Luffy temporarily wields a sword. One notable example is during the Dressrosa arc, when he briefly used a sword known as "Gomu Gomu no Kama" or "Gum-Gum Scythe." This weapon was a modified staff that took the form of a large blade, created by attaching a sword-shaped object to the end of his elongated arm. Luffy utilized this makeshift sword as part of his battle strategy.

It's important to note that Luffy's proficiency with swords is limited compared to his expertise in hand-to-hand combat and his Devil Fruit abilities. The use of a sword is not a consistent or defining aspect of Luffy's character or fighting style.