introduce variations of Gear Fourth, such as Tankman (vs. Charlotte Cracker in Whole Cake Island) and Snakeman (vs. Charlotte Katakuri), but the original Boundman form debuts exclusively in Dressrosa.

Monkey D. Luffy, the captain of the Straw Hat Pirates, unlocks during the Dressrosa Arc — specifically in Episode 726 of the anime and Chapter 784 of the manga.

Realizing that his previous techniques are no longer enough to defeat the Warlord, Luffy unveils a new form he developed during his two years of training on Rusukaina Island under the legendary pirate Silvers Rayleigh. He blows air into his muscles rather than his bones (as in Gear Third), inflating his entire upper body and coating his arms and torso with .