For example in chapter 907, something completely unexpected happened, which was Shanks having a meeting with the Goro and this left everyone completely shocked and confused and no one can figure out why Shanks one of the most loved characters in One Piece. And a Pirate was meeting with the leaders of the world government and so the theory was born that Shanks is actually a Celestial Dragon.
People from all over the world started putting the pieces together, fans notice noticed that way back in the God Valley incident, the Celestial Dragons were confirmed to be present on the island and when Garp and Roger defeated the Rocks Pirates, a child was somehow left behind and Roger ended up raising that child and if you were to match the date of the incident to Shank’s age, you find that Shanks was a baby around one years at the time.
Another point people realized was that high-ranking world government officials kept giving Shanks special privileges, like when he met with the Five Elders, they only agreed because it was Shanks saying “only because it’s you,” and all of this made no sense as why would the world give anything to Shanks who is a Pirate, why would Shanks will be able to do any of these unless he comes from a special bloodline or family that are the world’s Nobels and then in a special booklet of the One Piece movie.
Film red written by Oda himself, there’s a line from the movie in which the Five Elders say that Shanks belongs to the Figarland family. Confirming the just crazy theory that Shanks is indeed a Celestial Dragon who raised as a child by Goldie Roger.
6. Sanji is a Royal Prince
Now this theory was born all the way back in Alabasta where Sanji willingly used the Alias Mr. Prince. And fans thought of it as quite odd as to why would he do that and began theorizing. They noticed that Sanji seems to be from a special background the way he presents himself as he’s always dressed nicely and follows the typical stereotypes of a prince by not only seeing over women but princesses as well.Further adding to this theory, fans also noticed that all they know about Sanji is that he wanted to be a Chef. What they didn’t know was is Sanji’s parents. As Sanji never spoke of his parents being alive or dead, he just run away from home in order to fulfil his dream.
Sanji was not only born in the East Blue but in the North Blue. which is weird s how is some random 9-year-old kid able to run away and get from the North Blue to the East Blue without the help of powerful people. Which you would have if you were of course Royalty. And there is a Royal Kingdom called Lindell Kingdom which is in North Blue, in which Noland and his stories were based off. Fans speculated that Sanji could possibly been related to that Kingdom as that’s where he was born in the North Blue.
And then once the Straw Hats gained more publicity, Sanji’s Bounty Poster went from captured dead or alive to just alive. Possibly meaning that Sanji’s royal family wanted Sanji to return after he ran away.
And then in chapter 832, Sanji was confirmed to be a member of the Vince Smoke family. Making the theory that Sanji is a royal prince actually correct as the Vin Smoke family rule over the German Kingdom.
5. Lola is the Daughter of Big Mom
Now this theory started all the way back in Thriller Bark. Where we met Lola for the first time and Lola just outright says that her mother is an extremely powerful pirate and even gave the Straw Hats her Vivre Card and this sparked a ton of discussion in the community and theory started flooding in as people wanted to know well who is Lolas mother?Some fans even thought that she was the daughter of Miss Buckingham Stussy, due to the resemblance between her Edward Weevil. But the more popular theory was that Lolas mother was actually big mom as she met all the criteria for being a powerful pirate. But it also just made way more sense as the Straw Hats were kind of bounded to meet big mom in the future. Anyway making Lola’s Vivre Card well just more relevant and the final piece of evidence was the striking resemblance between Lola and big mom and the big mom pirates in general as big mom’s Jolly Roger had the same lips and hair color as Lola.
And this theory came true in chapter 835 as Lola was confirmed to be the daughter of big mom.
4. Buggy will become an Emperor of the sea
This theory started almost 10 years ago when Buggy become a Warlord. As fans had already been theorizing that he would become a warlord and so they took this theory to a new level by speculating that Buggy will become an emperor of the sea.The idea behind this theory is that if you didn’t know Buggy personally, his feat's were like incredible God-Tier if you would. He sailed with the king of the pirates broke out of the world’s most dangerous prison with a new army ready to die for him, then teamed up with Whitebeared at the war of the best and then was seen intimidating Shanks in Marineford.
Fans believed that once Luffy look down Kaido or the mom, there would be a temporary gap in power and Buggy will rise up take their spot and their underlings and rule over their land as a Yonko. And between his incredible look but also his reputation, fans genuinely believed it could be possible as he’s done things like this in the past.
This crazy theory came true in chapter 1053 where Buggy was not only confirmed to be an emperor of the sea along with Shank, Luffy, and Blackbeared but also has Hawkeye and Crocodile by his side and just how far is Buggy going to go.
It’s not honestly too crazy to think that Buggy could become the king of the Pirates.
3. Greenbull’s Abilities
Now this short but sweet theory happened when Greenbull met with Fujitora in Marijua when he stated that eating is really boring, i haven’t eaten in years.This statement shocked fans, with some believing that it’s foreshadowing for Greenbull potentially being a Samurai from the land of Wano as it’s well known that Samurai’s are never hungry. With other fans noticing that most Admirals with the most exception of Fujitora, all had Logia Devil Fruits and came up with the idea that Greenbull possessed a plant flower type Logia Devil Fruit.
And then this theory came true in chapter 1054. When it was revealed that Greenbull possesses the forest forest fruit or the Mori Mori No Mi.
2. Kaido can turn into a dragon
This theory started with Kinemon. When he said that he had a big Vendetta over dragons for some reason. And people started theorizing that Kinemon and Momonosuke said this and reacted like this was due to their hatred of Kaido ruling over the land of Wano as a dragon.Another point of evidence fans pointed out was that Kaido is known as the king of the Beasts, so he would have to be some sort of a beast himself right.
This theory was then confirmed in chapter 921 where Oda revealed Kaido is dragon form.
1. Kanjuro is a Traitor
This theory started out when people started speculating that there was a traitor helping the Beast Pirates and that’s how Jack has able to find Zoro so easily and how he knew that Raizo for a fact was there. But at the point in the story people who believed in this theory couldn’t pinpoint who it was as they really didn’t have too much information.But back in Wano fans learned that the same traitor was leaking information to both Orochi and Kaido.
And people thought that it was D. Orieno. Because there was just so much mystery shrouding his character but most people who believed this theory suspected it to be Kanjuro, because how just useless he was, fans went back and realized that this guy was so useless. He was borderline sabotaging. But the important piece of evidence fans had was the fact that in this Manga Panel before the retainers were sent forward in time, Kandra had two birds above him which he could have easily used to send information to Orochi.
And finally in chapter 974, it was revealed that Kanjuro was indeed the traitor.