Joy boy could have been one user of the Gomu Gomu no Mi and after awoken it, he became a continent puller. I think during the void century, the world was divided over the principle “Divide et impera”, fearing the world would reunite against the powerful people. Maybe the one piece isn’t a common treasure, but the continents are once again reunited into one and the Joy Boy of this generation will be the one to pull this incredible feat off. Perhaps Raftel is just ‘one piece’ of this ancient continent, split apart during the war of the void century, without which said continent cannot be recreated.
When Kaido said to the King that he could only have become Joyboy, he meant that he was the only one living that could accomplish moving entire islands with his own power. And that is why Oden wanted to reopen Wano to the rest of the world because he knew Joyboy would have eventually arrived and Wano was part of the big continent. That is also why the fishmen are waiting for Joy Boy, who is going to work with Shiraoshi (that is why Roger said it was just too soon for them because Shiraoshi-aka Poseidon (who can command the sea kings and can move an island underwater)-was yet to be born) and Zunisha to unify the ancient continent.
But there is one single problem arising from all of this: the Red Line. How can you even unify the continent if there is a giant wall that separates the entire world? That is when the other two ancient weapons come into play: Uranus and Poseidon. At least with Poseidon, at least with what we are given to know (even though I think there is more to it), the owner will be able to actually destroy the red line, allowing the contents to be moved “normally”; About Uranus, we know very little, if not nothing at all. We know that Uranus was the god of the sky, so here comes another theory of mine: As Shiraoshi can command sea kings and Momonosuke can command Zunisha, I think Luffy will be able to command Uranus.
But what is Uranus? As in other theories, I think Uranus will be the monster to come out of the giant egg that Roger found on the last island, and my guess is that, from that egg, a giant-Zunisha level-flying (the god of the sky) – the monster will come out that can only be commanded by Joyboy. That’s why both Momo and Luffy (as both Oden and Roger) are able to hear the voice of all things, and, even if that’s not confirmed, why do I think Shiraoshi is able as well? They are inextricably linked to the ancient weapons, and when they aren’t (as in the case of Momo, even though I doubt Pluton is just a super powerful ship), they are incredible giant monsters. Another reason why I think all of this is, again, because of what Kaido said, that “only he can do it.” I think Kaido knows about this prophecy (and maybe what the ONE PIECE is too), and he thinks Uranus is actually his devil fruit, making him the god of the sky and able to move continents within it. But that won’t be the case. So, to unify the world into ONE PIECE, we will need:
- And Joy Boy, who brings all people together (like someone we know, and this is actually why Whitebeard said Teach couldn’t have been the one Roger was waiting for): He will control Uranus, with which he will be able to move the Sky Islands on the ground and/or just surpass the Red Line;
- With the power of the sea kings, who will be able to move the Fishmen Islands to the surface with the power of the sea kings,
- Momonosuke, who will open and move Wano with the help of Zunisha,
- To break down the Red Line and connect the world (creating the All Blue for our Sanji).
I think it all makes sense with this, Doflamingo saying the celestial dragons will be dragged down (because MarieJoy will also be reunited with the other continents), the dream of Luffy and Roger (IMO to unite all the world), and why Ace and Sabo believe in him (because he always brings all the people around him), all blue, the void century, the timing of the prophecy, and the kings reunited as said by the sea kings. I also think that Raftel has the final map of the unified continent with the final treasure on it, which can be accessed only after putting all the pieces together.
I hope this theory was interesting to those of you who came here, and I will be happy to discuss it with you all in the comments!
TLDR:
- The Gomu Gomu no Mi Awakening transforms the user into a massive giant.
- The world was divided during the void century to prevent people from uniting and overthrowing kings.
- Laughtel has a map with the treasure that can only be found after putting all the pieces together.
- Uranus is a giant flying monster that can only be controlled by Joyboy (aka Luffy) (like Momo controls Zunisha and Shirahoshi, the sea kings), able to move sky islands on the ground;
- We will be able to relocate the Fishmen islands thanks to Poseidon.
- Pluton will destroy the Red Line, creating all blue;
- Kaido thinks he is Joy Boy and his DF is Uranus because he’s able to move continents in the air.
