Luffy befriends Shanks, intending to become a crew member. However, due to Luffy inadvertently eating the Gum-Gum Fruit, he trains to improve himself. During his early adulthood, he leaves his hometown to search for the "One Piece" and to form a pirate crew of his own, called the "Straw Hat Pirates". In the beginning of the series, Luffy meets a swordsman named Roronoa Zoro, the navigator and thief Nami, the cowardly marksman and inventor Usopp, and the first-class chef Sanji. He also encounters and defeats pirates in the East Blue, such as Buggy the Clown, Captain Kuro, Commodore Don Krieg, and Arlong. These actions cause him to be placed on the Marines' most wanted list with a bounty of 30 million in the fictional currency named berries. After entering the Grand Line, Luffy accepts an offer to return the princess of Alabasta, Nefertari Vivi, safely into her homeland to stop a rebellion, incited by a member of the Seven Warlords of the Sea, Sir Crocodile. Along the way, Luffy defeats the ruthless king Wapol while in Drum Island and finds a reindeer doctor named Tony Tony Chopper. In Alabasta, Luffy defeats Crocodile and the civil war ends, causing the World Government to raise Luffy's bounty to 100 million berries. Following Luffy's epic battle with Crocodile, he allows Crocodile's former second-in-command and archaeologist Nico Robin to join his crew.
Later on, the crew visits Skypiea. They get drawn into a war between two races, and Luffy defeats the god Eneru. He later meets Admiral Aokiji, an encounter that results in his defeat after he learns about Robin's heritage. The crew travels to Water 7 in an attempt to search for a shipwright. When Robin is captured by the intelligence agency Cipher Pol No. 9, the crew, along with a cyborg named Franky, follows Robin to Enies Lobby, and they are able to stop her execution. After the crew's battle against the CP9, Robin rejoins the crew, and each member receives their bounties; Luffy's bounty having been increased to 300 million berries. The crew returns to Water 7 and after the Going Merry breaks down, they get their second ship, the Thousand Sunny; there, they meet Luffy's grandfather, Vice-Admiral Monkey D. Garp. Shortly after, Franky joins the crew as the shipwright.
In the crew's attempt to enter the New World, they come across a ghost ship inhabited by a skeleton musician named Brook. When the crew discovers an island ship, Thriller Bark, they defeat the Warlord Gecko Moria, returning Brook's shadow in the process. After releasing the rest of the island's prisoners, Brook joins Luffy's crew. The crew goes to the Sabaody Archipelago in an attempt to coat their ship. However, an incident involving the auction of the mermaid Camie, results in the encounter against Admiral Kizaru, and the Warlord Bartholomew Kuma. Kuma defeats them by teleporting each of the crew members to different islands. Luffy lands on Amazon Lily, an island ruled by the Warlord Boa Hancock. Hancock eventually falls in love with Luffy and helps bring him to Impel Down, a prison, to save his brother Portgas D. Ace, who was imprisoned there after being defeated by Blackbeard. Luffy breaks into the prison and acquires foes-turned-allies, such as Crocodile and Buggy, as well as new allies, such as the Warlord Jimbei and Emporio Ivankov, releasing the prisoners in the process. The warden, Magellan, nearly kills Luffy, but he manages to escape from the prison to follow Ace to Marineford. After arriving in Marineford, Luffy is drawn into a war between the Marines and Whitebeard's pirate crews. Luffy manages to save Ace, but Ace's love for Luffy causes him to receive a fatal attack from Admiral Akainu. Luffy and Jimbei are hospitalized and evacuated from Marineford. When they return to Amazon Lily, Luffy realizes what has happened to Ace and looks back on how he and Ace first met. Silvers Rayleigh trains Luffy as his successor. Luffy returns to the Sabaody Archipelago from Rusukaina two years later and reunites with his crew, with his bounty being increased to 400 million berries.
