Oda established immediate consequences for Gear Fourth, which remain a staple of Luffy’s high-risk battles:
Luffy realizes he can’t move fast enough in this bulky form. He kicks the air repeatedly (similar to Geppo/Sky Walk) to propel himself, using his inflated, Haki-coated legs as shock absorbers and thrusters. gear 4 chapter
Gear 4 is a hybrid of Luffy’s previous concepts and Haki mastery. It’s bulky, bouncy, and allows Luffy to "fly"
. By blowing massive amounts of air into his muscles—rather than his bones—and coating them in heavy Armament Haki, Luffy creates a pressurized state that gives him explosive "tension". Boundman (The All-Rounder): The first form we see. It’s bulky, bouncy, and allows Luffy to "fly" by kicking the air, mimicking the CP9’s Moon Walk. Tankman (The Ultimate Defense): Used primarily against Cracker, this form turns Luffy’s belly into a black hole of rubbery defense that counters attacks with double the force. Snakeman (The Speed King): Sacrifices defense for pure, unpredictable speed. Luffy’s punches accelerate every time they bounce off the air, making them nearly impossible to dodge. The Cost of Absolute Power Every "Gear" comes with a drawback, and Gear 4 is particularly brutal. It demands a massive amount of the One Piece manga volumes (Vol.
Chapter 784 is officially available in Shueisha’s Weekly Shonen Jump archives, the One Piece manga volumes (Vol. 79), and via authorized platforms like Manga Plus or Viz Media.
The chapter showcased two signature moves of Boundman: