Prunce is an alien who is looklng for Precures with Fuwa. He seems to serve the Star Princess. But why?
Pruns will eventually transform a mankind-Form like the Star Princess. Fuwa who is in the unicorn form now will also be like mankind. The above is just a guess with three evidences.
Weak circumstantial evidence 1
He is with Fuwa from the first time
Weak circumstantial evidence 2
The name "Prunce" is like "Prince"
Weak circumstantial evidence 3
The Princess Star Color Pens of the 12 constellations has already finished, and if something happens to the final round, there will only be a re-awakening of the fairies, and then the prunce who was always with Fuwa can only be a valet or a prince.
From the above, Prince is the Prince!