In the sprawling narrative of One Piece , few power-ups have carried as much weight—literally and figuratively—as Monkey D. Luffy’s . The question of when he first uses it is not merely a matter of episode or chapter numbers; it marks a seismic shift in the series’ power scaling, stakes, and visual storytelling. After hundreds of chapters of relying on Gear Second (speed) and Gear Third (gigantic limbs), Luffy finally unveils his ace against a foe who seemed utterly untouchable.
: The first variation shown is Boundman (or Bounce-man). In this form, Luffy inflates his muscle structure while coating his arms, legs, and torso in Armament Haki , which gives him immense power and the ability to "fly" by kicking the air.
Chapter 784 , titled " Gear Fourth ," published on April 27, 2015.
: Luffy developed this technique during his two-year training period on the island of Rusukaina to combat the massive, powerful animals living there.
Monkey D. Luffy first uses during the climax of the Dressrosa Arc in his battle against Donquixote Doflamingo . Release Details
In Chapter 784 / Episode 726, against Doflamingo. But more importantly, he uses it at the perfect narrative moment —when hope is nearly extinguished, the villain is at his peak, and a new era of power is required. It is a 9/10 debut: visually stunning, tactically smart, and emotionally charged. The only thing holding it back from perfection is the sluggish pacing of the surrounding arc in the anime adaptation. For manga readers, it remains an all-time classic reveal.
This debut also set a template for future arcs: Gear Fourth would later evolve into Tankman, Snakeman, and eventually the balanced form we see in Wano. But every single one of those variants traces its DNA back to that bouncing, pink-haki-covered giant in the skies of Dressrosa.
If you’re watching the anime for the first time, do not skip the Dressrosa arc. Power through the slower middle episodes. Because when Luffy bites his arm and inflates, you’ll understand why this moment is still discussed in reverent tones years later.
