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

Uncover detailed explanations concerning Everything You Need to Know: When Does Luffy Use Gear 4 and How Does It Work.

When Luffy faced Kaido at the beginning of the Wano Country Arc, Gear 4 hit a hard ceiling. Boundman could knock the Emperor around the ruins of Kuri, but Luffy's strikes failed to penetrate Kaido's dragon scales. Kaido knocked Luffy out with a single Thunder Bagua, illustrating that brute compression was no longer enough against top-tier durability.

During his imprisonment in Udon, Luffy trained under Old Man Hyo to master Advanced Armament Haki (Ryuo). Instead of simply hardening his rubber skin, Luffy learned to project his Haki outward and channel it directly into an opponent's internal organs to trigger internal destruction.

By the time Luffy returned to the Onigashima rooftop, his Gear 4 attacks incorporated this internal emission. Boundman strikes like "Gomu Gomu no Kong Gatling" no longer battered harmlessly against Kaido's armor; they damaged Kaido's internal physiology. This upgrade proved that Gear 4 was not merely an interim powerup, but a flexible delivery system capable of channeling advanced Haki applications before his Mythical Zoan awakening surfaced.