Monkey D. Luffy is the captain of the Straw Hat Pirates and the central protagonist of the film. He is a young man with shaggy black hair, round black eyes, and a slim but muscular build. He is almost always seen wearing his signature straw hat, which he treasures as a keepsake from the pirate who inspired his dream. Luffy gained the properties of rubber after accidentally eating a Devil Fruit known as the Gum-Gum Fruit, which permanently turned his body into a stretchy, impact-absorbing material.

Luffy’s personality is defined by an unshakable optimism and a carefree, often reckless enthusiasm. He is straightforward and simple-minded, acting almost entirely on instinct and emotion. He has a huge appetite and an impulsive nature, often charging into situations without a plan. Despite this, he possesses a sharp intuition about people’s true intentions and an unwavering moral code. He becomes serious and fiercely aggressive when a friend is in danger or when he faces a powerful enemy. His primary motivation is to become the King of the Pirates, a goal he pursues with single-minded determination, but he also places immense value on the freedom and well-being of his crew and allies.

In the story of this film, Luffy and his crew travel to the desert kingdom of Alabasta to help Princess Nefertari Vivi overthrow the Warlord of the Sea Sir Crocodile and his criminal organization, Baroque Works. Luffy’s role is that of the decisive leader and primary fighter. He refuses to abandon Vivi even when the mission seems hopeless, demonstrating his deep sense of loyalty. His initial battle with Crocodile ends in a devastating defeat: Crocodile impales him with his poisoned hook and buries him alive in the sand. However, Luffy survives and later returns to face Crocodile again, using the moisture from his own blood to turn his rubber fists into a weapon that can strike Crocodile’s sand body. This climactic fight showcases Luffy’s tenacity and ability to adapt in battle.

Key relationships in the film include his bond with Vivi, whom he treats as a dear friend and protects without hesitation. His interactions with his crew—swordsman Roronoa Zoro, navigator Nami, sniper Usopp, cook Sanji, and the newly joined doctor Tony Tony Chopper—show a strong mutual trust and camaraderie. He also briefly clashes with Nico Robin, then known as Miss All Sunday, though she ultimately saves his life, hinting at her future change of heart.

The arc marks a significant point in Luffy’s development, establishing him as a hero who will risk everything for a friend, even when that friend is not a member of his crew. He suffers a humbling defeat and learns to overcome a foe whose abilities initially seem unbeatable. His notable abilities in this film are entirely based on his rubber body: he stretches his limbs to deliver powerful punches and kicks from a distance, uses his rubberized legs to launch himself like a rocket, and inflates his body for defensive or offensive maneuvers. He does not yet use the Gear transformations that appear later in the series. His greatest weapon, however, is his indomitable will and refusal to give up, which ultimately allows him to outlast and defeat a far more experienced enemy.