Everything You Need to Know: When Does Luffy Use Gear 4 and How Does It Work?

Trying to understand how everything You Need to Know: When Does Luffy Use Gear 4 and How Does It Work impacts your daily choices? Check out this overview and key takeaways.

The Whole Cake Island Arc exposed the limits of relying solely on Boundman. Faced with Sweet Commander Charlotte Cracker, Luffy discovered that Boundman could shatter biscuit warriors individually, but could not overcome Cracker’s endless reinforcements before his Haki timer expired. In Episode 806 (Chapter 842), after gorging on biscuits for eleven straight hours with Nami's assistance, Luffy revealed Tankman: Stuffed Version.

Tankman concentrated mass into Luffy's abdomen while saturating it with defensive Haki. When Cracker attempted to pierce the rubber belly with his sword, the blade failed to break skin. Luffy simply absorbed the strike and expelled Cracker across the island with the "Gomu Gomu no Cannonball."

The fight against Charlotte Katakuri in the Mirro-World required an entirely different evolution. Katakuri's advanced Kenbunshoku Haki (Future Sight) rendered Boundman's heavy telegraphs useless. In response, Luffy revealed Snakeman in Episode 870 (Chapter 895). Snakeman stripped away the immense torso bulk of Boundman, redistributing air and Haki to optimize striking velocity.

Through attacks like "Gomu Gomu no King Cobra," Snakeman allowed Luffy's fists to change direction at sharp angles without losing momentum. Each time an attack missed and bent around Katakuri's body, it accelerated, eventually outstripping Katakuri's Future Sight windows and landing the critical strikes that decided the duel.