First poseidon-plouto-uranus are all greek words.
Uranus (Ουρανός) =SKY
Poseidon '(Ποσειδόνας)' was the god of SEA
Plouto (Πλούτονας) known as Hades (Άδεις) as well, was the god of UNDERWOLD
Sky-Sea-Underworld so we can understand that the names are not just random and they symbolise each something.
POSEIDON=Shirahoshi that is a MERMAID and can communicate-control with SEA kings.
URANUS= SKYPIEA person that can.....???
PLUTO=HUMAN(?) pirate king(???) what could it be??
let me hear your theories and thoughts:) (about the names i am sure because i am Greek btw)