There is a fairly interesting connection between two concepts that have been developed in the story for a while now. I have first seen it brought up in a video about why Zunesha might be Pluton. While this was obviously wrong, the general idea still stands, because, as we learned in recent chapters, the Wano arc is very much still connected to Pluton.
So, here is a connection that is either coincidental or one of Oda’s craziest acts of foreshadowing yet:
In Alabasta we learn about the existence of the ancient weapon Pluton for the first time. In the same arc, we are introduced to the possibility of objects being fed devil fruits. It is specifically a weapon that has “eaten” a devil fruit.
The next time Pluton is at the center of the story and we learn a little bit more about its nature, is during Water 7 / Enies Lobby. Here the pattern actually forms, because Funkfreed, a sword that was fed a devil fruit, is introduced.
And coincidentally (?) there is a lot of focus put on this weird animal-weapon whenever Spandam talks about Pluton.
Now, as we look to Wano, what really sells the idea that the ancient weapon Pluton is a battleship that was fed a Zoan fruit (probably of the mythical kind) is the new information on Zoans we received during the arc. We get confirmation that these kinds of fruits do indeed have a will of their own, something that ties back all the way to Alabasta and the very first sentient weapon we saw.
This is really interesting, because a battle ship underwater that ate a devil fruit would have it’s powers taken away, but would also not die since its original form is inanimate. This could also be the reason why Pluton is sleeping (maybe in a literal sense) specifically in Wano because the natural sea stone is keeping it powered down. And it’s totally submerged in water.
Alabasta and Enies Lobby, the two arcs that revealed the most about the ancient weapon Pluton, both feature weapons that were fed Zoan fruits. Now, in Wano, we had some focus on the will of devil fruits and saw a ton of Zoan users. This leads me to believe that Oda was hiding the nature of Pluton, which is actually a sentient battleship that ate a Zoan fruit, in plain sight all along. Or it is just a funny coincidence, who knows?
Theory by FlowOfMotion (https://www.reddit.com/user/FlowOfMotion)