About the Wano Country Arc
The Ninja-Pirate-Mink-Samurai Alliance gather their forces in Wano Country and prepare for their inevitable clash against the Beasts Pirates. The history of Kouzuki Oden and his ties to Wano Country, Whitebeard and Gol D. Roger are revealed, and the Alliance assaults Onigashima to take down the allied forces of Kaidou and Big Mom once and for all. The resulting battle, as well as the events during the recent Levely, cause the world to go through dramatic changes.
The Wano Country Arc is uniquely split into three officially defined acts (第幕, dai maku?). Between each act is a brief interstitial of one or two chapters. The divisions of the acts are as follows:
Nekomamushi and the Guardians arrived on Sphinx, where Marco resided and worked as a doctor. Marco revealed that Sphinx was Whitebeard's homeland and his last keepsake. With Edward Weevil and Buckin hunting for Whitebeard's inheritance, Marco anticipated that they would attack this place, and so elected to stay behind and protect it instead of joining the Ninja-Pirate-Mink-Samurai Alliance against Kaidou. However, he told Nekomamushi to give Luffy a message from him once he arrived at Wano Country.
Sometime later, Luffy's group read about the Levely while sailing to Wano. Nami noticed an article about Kaidou and Big Mom, but was unable to read it due to Sanji and Chopper cutting pictures out. The crew then came to a stormy area that looked like Wano, and as they sailed through it, they encountered a school of giant carp. They then came to the bottom of a massive waterfall, and Luffy grabbed onto two of the jumping carp to pull themselves up. At the top of the waterfall was a whirlpool, and Luffy had Sanji fly the others to land. When he tried to follow them, an octopus that had boarded the Thousand Sunny held him back, causing him to go down into the whirlpool.