Monkey D. Luffy is the protagonist of the popular manga and anime series, One Piece. He is the captain of the Straw Hat Pirates and possesses the power of the Gum-Gum Fruit, which gives him incredible stretching abilities. Luffy's goal is to find the legendary treasure known as One Piece and become the Pirate King. Along his journey, he faces various challenges, battles powerful enemies, and forms alliances with other pirates. Luffy is known for his optimistic and carefree personality, as well as his unwavering loyalty to his crew. His signature catchphrase is 'I'm gonna be the Pirate King!'.