Charlotte Cracker (salah satu Sweet Commander Big Mom).
Tubuh Luffy menjadi besar dan kekar, dilapisi Armament Haki (Busoshoku Haki) yang pekat, dan terus-menerus memantul (bounce) karena tekanan udara tinggi di dalam ototnya. Gear 4: Tankman (Versi Kenman) Episode: 806. gear 4 luffy episode berapa
(specifically, "The Boundman Appears! Luffy's New Form, Gear 4!") Charlotte Cracker (salah satu Sweet Commander Big Mom)
In Gear 4, Luffy's body expands and his muscles grow, allowing him to deliver incredibly powerful blows. He can also change the size of his body parts, making him more versatile and unpredictable in battle. "The Boundman Appears! Luffy's New Form
Teknik ini dikembangkan Luffy selama pelatihannya di Pulau Rusukaina bersama . Luffy's Best Gear 4 Moments in One Piece, Ranked - CBR