One Piece: Joy Boy's History Explained
While there is still plenty of ground to cover in Eiichiro Oda's acclaimed and notoriously long anime series "One Piece," manga readers will know that the end of the long-running Wano Country Arc is close at hand — with the climactic battle between Monkey D. Luffy and Kaido nearly at an end. Throughout this arc (and even during the middle of this battle) we've heard several references to a mysterious and legendary figure known as Joy Boy, who seems like he might have an impact on this fight down the stretch.
This name first popped up during the Fish-Man Island Arc, when it was revealed that Joy Boy was the original owner of the One Piece — a mythical treasure that was eventually discovered by Gol D. Roger on an island called Laugh Tale. At his execution, Roger promised that any pirate who could find the One Piece would become the next Pirate King — something that served as the impetus for the entire series since the end goal for Luffy and the Straw Hat Pirates is to claim the One Piece and establish Luffy as the next Pirate King.
Because tracking down the One Piece is the impetus behind the entire series, it's safe to say that the mysterious history of Joy Boy is crucial to the story of "One Piece" and over the years we've uncovered plenty of information about this legendary figure — including his possible connections to the Ancient Kingdom, the Sea Kings of Fish-Man Island, and Wano itself.
Breaking the promise with Fish-Man Island
In Episode 569 of "One Piece," King Neptune of the Ryugu Kingdom on Fish-Man island explains that the island once came to an agreement with the mysterious Joy Boy more than 800 years prior to the events of the series. This took place during the "Void Century," an era that was completely wiped from history by the World Government — hence all of the mystery surrounding Joy Boy and his exploits.
Neptune explains that Joy Boy promised to raise Fish-Man Island to the surface with the help of a ship called Noah and the monsters known as "Sea Kings" — though he went on to break this promise, possibly due to his involvement with the Ancient Kingdom's war against the 20 Kings. Joy Boy left behind a Poneglyph that contained an apology for his betrayal and another promise that he would return 800 years later to fulfill his oath. This prophecy is expended upon during a flashback in Episode 968 — where we see Gol D. Roger discover the One Piece treasure and learn the true history of the Void Century, before mysteriously claiming that he was too early in his arrival on the island.
This flashback continues into Episode 969, where Kozuki Oden and Roger travel back to Fish-Man Island and hear the monstrous Sea Kings prophesying that the one who would lead them (fulfilling Joy Boy's oath) would come in 25 years alongside the rebirth of Poseidon — a prophecy which seems to line up with Monkey D. Luffy's visit to the island.
Kaidou's search for Joy Boy
Following the discovery of the One Piece, Kozuki Oden returned to his homeland of Wano with plans to prepare the country for the imminent return of Joy Boy, though these plans went south when Kaidou and the new shogun Kurozumi Orochi defeated and executed Oden. This is significant because Kaidou himself has a unique connection to the legend of Joy Boy, though for this we have to work from the manga and skip ahead of what has currently been adapted for the anime.
Within the anime, the name Joy Boy most recently appeared in Episode 1034 when Kaidou knocked Monkey D. Luffy off the roof of Skull Dome and said "You couldn't be Joy Boy... either, it seems." While this line might seem rather mysterious to anime-only fans of "One Piece," flashbacks from the manga reveal that Kaidou has been searching for the next reincarnation of Joy Boy for years –- ever since his right-hand-man, King, first discussed the legend with him in his earliest days of piracy. It's unclear where exactly this obsession with finding the next Joy Boy comes from, though Kaidou's comment to Luffy makes it seem like he's sought through plenty of candidates before deciding Luffy might be Joy Boy.
Alternatively, it could mean that Kaidou himself had dreams to become the next Joy Boy since we know that he has an insatiable lust for power and King himself once hoped that Kaidou could become the next Joy Boy. Given all of the references to Joy Boy scattered throughout this arc (as well as Kaidou's belief that Luffy is indeed the reincarnation of Joy Boy), fans would do well to keep the legend of Joy Boy in mind as Kaidou and Luffy's battle reaches its dramatic conclusion.