In this theory I am going to talk about Joy Boy and the Ancient Weapons. Don't get me wrong I am not talking about Joy Boy and the Ancient Weapon who exist during the Void Century I am talking about the new Joy Boy and the new Ancient Weapons who are part of the current era of the OPverse. But before going to the new era I have to talk about the void century giving a brief summary of what we know to show what we can already conclude and what kind of hints it gives us about the new era.
Informations about the Void Century
800 years ago was the end(or beginning I am not sure) of a century which is now known as the void century, its called Void Century cause the World Goverment tried to erase all informations about this century and also prevent people from talking about it. But there exist the indestructable Poneglyphs written in a language with only a few left who are able to read, more precious the only known living character able to read this language is actually Nico Robin. Nico Robin is from an island called Ohara known for the Scholars of Ohara a group of people who studied the history of the OPverse incl. to find out everything about the Void Century by decyphering the Poneglyphs. Everyone of the Scholars of Ohara (besides Robin) were killed by a Buster Call while Robin was still a kid. In Robins backflash Oda revealed the final words of Prof. Clover ther leader of the Sholar of Ohara.
These final words revealed a lot. During the Void Century there was an enormous Kingdom which prided itself for its great power. But this Kingdom doesn't exist anymore it can be concluded that this Kingdom was defeated by an alliance of the 20 nations which have become the leading nations of the current World Goverment.
The next piece of important information is what we learned about the Poneglyphs on Zou. There it was told the Poneglyphs were created by the Kozuki Clan of Wano.
In the flashback of Oden we learned that the Kozuki Clan was also responsible for closing boarders of Wano that the clan did it to protect Wano from a great evil.
In my opinion its quite obvious that this great evil was the alliance which is now know as the World Goverment. With this one can conclude that the Ancient Kingdom ordered the Poneglyphs the moment they realize they are going to loose the war and that the Poneglyphs containing the informations about the Void Century were given to their allies. Meaning every nation who was in the possesion of a Poneglyph was an ally of the Ancient Kingdom. Besides history these Poneglyphs also contains thel locations and informations of the so called Ancient Weapons known Poseidon, Pluton and Uranus each of them capable of mass destruction.
These weapons are not only meant to be objects, but also living beings. Pluton is a ship while Poseidon is a Mermaid Princess able to control the Sea Kings while Uranus is still completly unknown. Combining that the Poneglyphs contains informations about the Ancient Weapons with the assumption that the Poneglyphs were ordered by the Ancient Kingdom and hand over to their allies one can conclude that the Ancient Kingdom and their allies were in the possesion of these Weapons.
Another thing we learned about the Poneglyphs that there are 4 special Poneglyphs, known as the Road Poneglyphs. These Poneglyphs contain the informations how to reach the island Laugh Tale. This lead to the assumption that the Ancient Kingodom was domiciled on that Island.
Roger and his crew manage to reach Laugh Tale and learned anything about the past and a man known as Joy Boy. They also learned that Joy Boy will return 20 years later, which is "now" in the current One Piece timeline. Thats also why Oden decided to go back home and open the boarders of Wano.
This leads to the assumption that Joy Boy was something like the leader of the Ancient Kingdom. And since we learned that with Joy Boy also Poseidon have to return at given time
I am going to say that also the other 2 Ancient Weapons will return too.
The return of Joy Boy
To figure out who Joy Boy is ne might ask if there are still descandants from the Ancient Kingdom, I would say yes. The 20 nations (except Nefertari family/Alabasta) decided to live on top of the Redline and become a group named Celestial Dragons. These Celestial Dragons are the privileged minority ruling over the World acting like being Gods. In Laws flashback we learned that the father of Doflamingo and Corazon was a Celestial Dragon who decided to become a normal human.
In one point of the backflash Law asked Corazon whats the meaning of the D., followed by Corazon telling him that the D. stands for "Gods natural enemy".
Especially with Corazon saying Celestial Dragons can be seen as these gods one can conclude that the D.'s are the descandents of civilisation. This results in the assumption that the new Joy Boy should be part this "D. Clan". And who would fit better than the main protagonist of One Piece ? Who is actually called Monkey D. Luffy and thus part of this "D. Clan". Are there more hints, of course there are! I expect many would go the and compare Luffy with Roger, but since we learned through the story of Oden that Roger never was a "Joy Boy" I will try a different approach (long time many expect sth. like Joy Boy -> ... -> Roger -> Luffy).
At Twin Cape the Strawhat Pirates met Crocus who was the doctor of the Jolly Roger Pirates. After Strawhats left Twin Cape we saw Crocus talking to himself.
The ones we were waiting for, for me definetly a reference to the outcome of Jolly Roger Laugh Tale adventure. Also interisting in Odens flashblack we saw the Sea Kings saying that ones the Kings returns the whales will be happy again.
Now look back what we see the moment Strawhat Pirates entered the New World for the first time!
I think there was actually noone doubting anymore that Luffy is or will become the new Joy Boy, but I hope these points just strengthen this idea. Lets head to the next one!
The return of Poseidon
Since we already that Princess Shirahoshi is the Ancient Weapon Poseidon there is not much more to say about it.
So lets directly head over to the next one.
The return of Pluton
Pluton is known as the world's worst battle ship.
A ship capable of destroying a whole island with a single blast and it said to be hidden somewhere in Alabasta.
And we know that the position of Pluton is noted on the Poneglyph in the secret tomb below the plast of Alabasta and Cobra is aware of it.
At this point some of you migh have already realized that there is something that does not fit. On the one hand Nefertary was part of the alliance that took down the Ancient Kingdom during the Void Century on the other hand they were hiding not only a Poneglyph but also the Ancient Weapon Pluto from the World Goverment. The first part toally fits with Robins reaction towards Cobra saying they were protecting the Poneglyph.
Bur I actually think Cobra was telling the truth. I mean even the 5 Elders figured out that the Nefertari family have to be traitors cause they were the only ones who decided to live on the surface 800 years ago.
An interisting figure introduced during Reverie is the hidden King of the world known as Im. And we saw Im with pictures of 4 characters: Luffy, Teach, Shirahoshi and Vivi. One can easily find explanation why the first 3, but why Vivi? And also why was he holding it while moving to the throne.
On top of that we learned that after Reverie ended an incident occured, an incident with the Kingdom of Alabasta being involved.
Adding to this that the World Goverment already started to search for the Ancient Weapon (especially Pluton).
This lead to the assumption that the World Goverment figured out the location of Pluton! And I won't be suprised that the incident will end up being resolved with the World Goverment end up finding the Pluton!
The ones who remeber Water 7 saga well will know in which direction this will lead! In Water 7 saga we learned that the blueprints of Pluton still exist.
These blueprints has been passed down in a line of incredible shipwrights to protect them from falling into the wrong hands and use them to build a new Pluton in case that the first Pluton will be revived. Does this mean Franky will build a new Pluton once he heard about the ressurection of the first one? No I don't think so cause I am convinced that he really destroyed the blueprints of Pluton (without a copy of existing).
But like Shirahoshi is a new Poseidon I think the Thousand Sunny can be seen as new Pluton! Does this mean Thousand Sunny was build based on the blueprints of Pluton? Actually not I think Franky manage to create a new Pluton completly independent from the first one and I am going to say the new one will end up surpassing the first one!
The return of Uranus
So far we know nothing about the Ancient Weapon Uranus besides this weapon have to be as strong as a warship able to destroy a whole island or a mermaid princess who is able to control the Sea Kings. One common guess for Uranus is that it could be Momonosuke. Momonosuke is somehow able to command Zunisha an elephant almost as big as an island.
This power is almost identically to the power of Poseidon and this is also a reason why I am doubting that Momonosuke could actually be Uranus. Another reason for doubting Momonosuke to be Uranus is actually that Uranus wasn't mentioned a single time during Odens story. Since Poseidon was mentioned Uranus should have been mentioned in connection with Wano.
Another common guess is that Luffy could be Uranus thus Joy Boy would have been Uranus, but here is also a big error for me because for me Joy Boy and Uranus have to be 2 different things cause both names appear on Poneglyphs (Uranus never appeard officially, but Poneglyphs should contain infos about Uranus).
My approach for this theory is to take a look at the wanted posters from Im. There we had Luffy who stands for Joy Boy, Shirahoshi who is the new Poseidon and Vivi who is connected to Pluton with that the only who is left out so far is Blackbeard!
Teach being Uranus doubt it, Teach being somehow connected to Uranus definetly possible. And I think the key to this is Blackbeards connection to Rocks D. Xebec. I know this connection is not confirmed, but definetly hinted. One of the greatest hint is that Blackbeards ship is called Saber of Xebec (an information we got from Vivre Card Databook. Xebec wasn't jus the captain of the most fearsome Pirate Crew ever seen in OPveres and aimed to become the King.
But 38 years ago Xebec and his crew has been defeated on God Valley.
To protect the Celestial Dragons and their slaves Garp and Roger joined forces.
And even so Garp alone got the full credit for the defeat of the Rocks Pirates the World Goverment let God Valley vanish, because the desired very much to keep secret of the existence of this island.
Why did the pirate who tried to become King attack God Valley? Why did the World Goverment make secret about the existence of God Valley? Actually there is one reasonable answer for it "Uranus". Xebec tried to obtain Uranus while the WG fear the power of the Ancient Weapons, so yeah Uranus located at God Valley makes a lot of sense.
Lets try to get a step further. Looking at the silhouette of God Valley it somehow reminds me on the silhouettte of Emerald City in Wizard of Oz.
Suprinsingly there is a myth about about an Emerald City in OPverse.
The story of a legendary pirate captain searching for a powerful weapon in Emerald City, a place not existing on any map, would be something a character like Bellamy would considere as fairytale. Lets continue with the assumption that Emerald City was indeed a city on God Valley and the place connected to Uranus and add the meaning of Uranus. The Ancient Weapons are named after Gods and Uranus resembles the Greek God of the Sky thats why many believe that Uranus powers are related to the weather. Combining weather with Oz I directly have to think about the Wicked Witch of the East who is a powerful Witch able to control the weather. And actually it shouldn't take long for a One Piece fan to find a character who perfectly resembles the Wicked Witch of the East and that is Nami! She is coming from the East Blue, was called witch many times and is able to control the weather with her "magic wand".
On top of the mentioned points Nami also have a supernatural sense for weather.
But Nami connected to Uranus, does it fit with her plot? Actually much better then one might think and therefore I recommend to take a look at Namis background story we learned in the Arlong Park arc. We know Bellermere wasn't the real mother of Nami and Nojiko (and Nami and Nojiki are not even siblings). Bellemere actually found Nami and Nojiki (or better saying Nojiko found Nami and Bellemere) after a huge fight happpen on an (for us) unknown island.
Bellemere decided to quit Marines and become the mother for Nojiko and Nami, this looks fine while it actually doesn't. Back then Bellemere reached Cocoyasi Village half dead with a tiny boat during a storm
followed by making a secret of the existence of theses 2 girls.
This let me believe that the situation regarding Nami and Nojiki can be compared to situations like World Goverment killing unborn childs trying to exterminate Rogers blood or killing innocent refugees to make sure no Scholar of Ohara may survive.
Finally this follow ony of the Main aspects of the New World saga which seems to be resolving the origins of Luffy and his first 4 crewmembers who started with him in East Blue. It started with Sanjis family plot in Whole Cake Island, now we have the ties between Zoro and Wano, the story of Luffy will definetly come on Laugh Tale and I have actually no doubt the Usopps arc will become Elbaf. Thus an Arc with Nami end up being tied to Uranus resolving her past would make a lot of sense also storywise.
What we learned about the Void Century so fat is that there existed an powerful kingdom ruled (or leaded) by man known as Joy Boy. Even so this Kingdom was in the possesion of the 3 Ancient Weapons Pluton, Poseidon and Uranus it got defeated by a powerful aliance of 20 nations. The winning aliance became the founding members of the current World Goverment. Roger found out everything about the Void Century and that there is a prophecy that Joy Boy and the Ancient Weapons will return 800 years after the war was lost, 20 years after Roger reached Laugh Tale, now OPverse. Everything points towards Luffy being the new Joy Boy and he already befriended with Shirahoshi who is the new Poseidon. Pluton is hidden somewhere in Alabasta by a traitor of the alliance who defeated the Ancient Kingdom. An incident occured involving Alabasta leading to the assumption the World Goverment is going to find the old Pluton. But following the pattern of Weapons returning it seems like Franky inherited the will of the shipwright who created Pluton and manage to build a new Pluton, the Thousand Sunny! Not much is known about Uranus, but it seems like Uranus origins are on God Valley thats a good explanation for both Xebec attacking God Valley and Word Goverement makinf a secret of the existence of this island. God Valley could also be the key to resolve 2 missing stories "Emerald City" and "Namis past" which leads to Nami being the key to find Uranus (or maybe Nami herself being Uranus).
I really hope you enjoyed reading this theory :)
seiryu Marco Polo this shall be my entry