This is just my theory and I want it to be like this. Just consider this a wild theory and my hope for the end of the One Piece movie.
Okay, let's theorize since the beginning of the Mugiwara Pirates Monkey D Luffy and his crewmates managed to go to Lake and get one piece and find out the secret about what eating the letter 'D' is, find out the mystery of the void century, and find out everything that the government has hidden.
After hearing that Luffy and his crewmates managed to get one piece, Im Sama was furious and the Kurohige Pirates, the traitor to the Whitebeard Pirates who couldn't accept it if he wasn't the one who got one piece, didn't accept it either, Im Sama declared a war against the Mugiwara Pirates, and this became big news that spread.
The Sword members who already knew about the world's secrets that had been hidden by the government, immediately decided to leave the Marine troops and join Luffy's pirate crew, All the pirates who heard about the war headed to the island where the war took place; Akagami, Buggy the lucky man, Kurohige, Even the Revolutionary Army also joined the war.
After arriving at the war, many were surprised that Kurohige had obtained an ancient weapon called Pluton in the land of Wano, the place where Luffy with his fifth Gear defeated Kaido the Dragon man, and Im also had an Ancient weapon of mass destruction, namely Uranus, Not wanting to lose, Luffy who joined the fish-man army also had the Ancient Poseidon weapon.
Here the biggest war in the history of the One Piece world took place. Kurohige worked with Im-sama, Gorosei, Admiral who would fight Mugiwara, Akagami, Buggy, Miwhak, Law, and the Revolutionary Army.
Kurohige who had obtained his third Devil Fruit and the Pluton weapon of destruction became very strong and he fought Luffy, and here we are also shown the power of Dragon which has made us curious, Dragon and Shank work together to fight against Im-sama.
Luffy's crew, Yamato (Luffy's 10th crew) and Sword fought against Teach's Crew (Blackbeard), Shank's Crew and the Elbaff knights vs Gorosei, and Buggy's Crew, Crocodile, Miwhak the eagle eye, and the Revolutionary troops vs Admiral and vice Admiral.
Here we also know that Aokiji returned to sword and when the war took place, Aokiji the ice man fought to the death against Akainu the Lava Man. Because of the huge effects of the war, Redline broke and Allblue was created.
After a long war, finally the pirate troops of Shank, Mugiwara, Buggy, the revolutionary troops, and members of sword won, and sword formed a true government.
At the end of the story Luffy returns Shank's straw hat and they fight (the fight is not serious), and Shank loses, but Shank still gives the hat to Luffy as a gift because Shank also got the straw hat from Roger, then Zoro the swordsman vs his teacher Miwhak, the fight is won by Zoro, after that there is a time skip 1 month later Luffy and his friends are seen laughing together.
this is just my theory, please don't bully me. fellow Anime lovers don't bully each other. greetings. btw the picture is the result of my painting with a sketchbook and colored pencils.