There’s been a common theory on the forums saying that Momonosuke is Uranus, this is due to his similarities in his ability to command a being similar to Shirahoshi aka Poseidon.
However, an argument against this theory is that it would be strange to have 2 individuals as a weapon whilst the 3rd is a battleship.
But I think there’s more to it and it’s not just 3 ancient weapons.
Let’s take a look at the current timeline. Right now we have 3 great forces which are known as the balance of power. It consists of the Yonko, Shichibukai (now replaced by SSG) and the Marines. The forces are not equal and to balance it out, the World Government formed the Shichibukai (now replaced by SSG).
A simple equation to this power balance is Yonkos = Shichibukai (now SSG) + Marines.
Now here’s where the theory starts:
During the void century, there were 2 individuals who possessed extraordinary powers. They became known as Poseidon and Uranus. The World Government feared their powers and labelled them as weapons.
In order to oppose them, the World Government created their own man-made weapon: Pluton. Unlike Poseidon and Uranus, this wasn’t an individual but rather a gigantic battleship capable of countering them.
In other words, there was something similar to a balance of power which was Uranus + Poseidon = Pluton.
Now unlike Uranus and Poseidon, pluton cannot be reborn as it’s an object so it can only be discovered or rebuilt using the blueprints.
In the current timeline, Momonosuke is Uranus. He is destined to meet Shirahoshi aka Poseidon. This is the prophecy mentioned by the sea-kings in Oden’s flashback where they stated that the 2 sovereigns will meet.
An argument against this is that the sea-kings’ prophecy suggested that the 2 sovereigns are not born yet whilst Momonosuke was already born. However, because of Toki’s action of sending Momonosuke to the future 20 years, this could have distorted the prediction.
An interesting thing is that a prediction for when the other sovereign would be born wasn’t given but suggested he/she would come from a distant sea. Another thing, Momonosuke wasn’t on the ship during this part of the voyage and this might’ve been due to the sea-kings recognising him as Uranus.
If Momonosuke is Uranus, what are his true powers?
Well, a fitting power for the heir of the Kozuki will be the ability to turn the carps swimming in Wano’s rivers into dragons and control them. Uranus is the god of the sky so it’s fair that Momonosuke has a power related to that and what is better than controlling an army of dragons that can fly.
This will also tie in with the myth of a carp turning into a dragon after swimming upstream. This might sound familiar, as a way to get into Wano is to use a carp that is swimming upstream.
Interestingly, Shirahoshi’s mother: Queen Otohime was a goldfish mermaid which is part of the carp family, and the royal palace in Fishman island is called Ryugu Palace which translates to “Dragon Imperial Palace”.
Also, Momonosuke himself ate an artificial devil fruit which turned him into a dragon. The villain of the arc is also a dragon devil fruit user and Kinnemon hates dragons because of that.
Wouldn’t it be ironic if Momonosuke’s powers are to command dragons which will pretty much makes him the “King of beasts”.
Another interesting point is that Momonosuke’s dragon form has a very similar colour scheme to Shirahoshi (pink with gold accents).
Anyway, with Shirahoshi controlling the sea-kings in the ocean and Momonosuke controlling dragons in the sky. It would truly be a frightening power and deadly combo.
Theory by 50thsun.