Toei Animation, for the first time in a long while, leaned heavily into the aesthetic from the Thriller Bark arc. The coloring shifted to a darker, redder tone, and Luffy’s face lost its usual goofy charm, replaced by a focused, almost hollow gaze.
The episode’s climax features Luffy , slamming him into the ground, and then finishing with a King Kong Gun that sends the Warlord crashing through the entire city, cracking the underground port and shaking the entire island. The sheer force and visual of a bouncing, black-armored giant screaming "Gomu Gomu no... KING KONG GUN!" became instantly iconic.
While the technique debuts in episode 726, Luffy reveals different "forms" of Gear 4 across several critical episodes: 4 gear luffy episode
This initial reaction—confusion and perhaps a bit of disappointment—was intentional.
Episode 806 – Used during the battle against Charlotte Cracker. Luffy adopts this form after consuming a massive amount of "Biscuits," increasing his defensive "rebound" power. Toei Animation, for the first time in a
: Luffy coats his forearm in Armament Haki , bites into it, and blows air directly into his muscles.
Doflamingo, initially laughing at the comical sight, quickly realizes he made a mistake. Luffy’s voice drops, becoming deep and serious. The sheer force and visual of a bouncing,
Looking back, Episode 726 changed the trajectory of the series. It set the standard for future transformations like Snakeman and, eventually, Gear 5. It proved that Luffy’s "Gears" aren't just biological changes, but creative inventions that utilize physics and willpower.