On the page of Osea it was write:" Probable Real World Counterpart: United States of America..."
But i think for the flag, can also be the Europe flag for 2 reason:
1- for the arrangement of stars in a circle.
2- on the Osean flag there is 6 Big star and one little... the first European flag had six stars (now twelve) who were to symbolize the first 6 European countries. While, it had made a proposal to add a little star to symbolize the Luxembourg ... this proposal was rejected.
What do you think about that?