We know very little about them ONE PIECE's past. One of the great secrets of the saga revolves around a specific time that has seemingly completely disappeared from history, but other events have also remained more or less hidden in the shadows. However, the new episode of ONE PIECE that airs on Crunchyroll reveals some of them.
Before the start of Wano act three, ONE PIECE 958 has decided to share the events of the outside world once again, leaving aside the samurai island where Luffy and his companions are. Sengoku the Buddha, now retired Marine and representative of the youth's growth, will explain the events.
During this time, Sengoku tells the story of God Valley, an island where the most important battle of recent times took place. A few years earlier, this land was the scene of the battle between the Pirate Rocks, the Garp-led navy, and the legendary pirate king Gol D. Roger. Garp and Roger have teamed up to defeat Rocks, the most dangerous pirate of the time, whose crew were heavyweights like Whitebeard, Big Mom and Kaido.
After the events in which the Rocks were defeated, God Valley has been completely erased from the maps while Garp received honors from around the world that became legendary today. However, it was also the time when the future emperors parted and set out on their way. And that led to them being Kaido and Big Mom with the monstrous bounties known today.