After the latest chapter I was wondering about Poseidon, apparently it's some kind of "force" that appears to grow within the royal family of FI....but what does this have to do with Pluton? (which is a battleship)
Maybe it has to do with the names, Poseidon is the greek god of the sea and earth, while Pluton is the ROMAN god of the underworld, for you who don't know the only difference between the greek and roman myths is the names, nothing else.
So i think it's possibly a reference to the Romans taking the gods of the greek, but only change the names. Imagine the greeks as "forces" and the romans as "humans", and poseidon is a force but Pluton is a material, I think the roman named weapons (made by humans) are copy's of the force's (like shirahoshi's power).
Sorry for being so confusing >.<