Joy Boy is a significant figure in the world of One Piece, a popular manga and anime series created by Eiichiro Oda. He lived during the Void Century, a mysterious period in the series' history, and is known for his connection to the One Piece treasure and the Poneglyphs, ancient stone tablets that hold important information about the world. Joy Boy is best known for his promise to the inhabitants of Fish-Man Island, which he failed to fulfill. This promise is linked to the legendary treasure and the concept of freedom, making Joy Boy a symbol of hope and adventure in the series. His legacy continues to influence the main characters, particularly Monkey D. Luffy.