She’s the Prince. And that costume too waaaaaay too long to make!
I think she looks pretty cute, even if you aren’t familiar with the Katamari games. Of course, if you’re confused you can visit the official Katamari website (fair warning: there is music), or consult the all-knowing Wikipedia. And then there’s always YouTube (na na na na na na na na na, Katamari Damacy).
Happy Halloween!