Platinum Princess

The Platinum Princess is a legendary figure, a girl who is chosen every 1,000 years.

History
As the legend goes, once the Eternal Tiara is complete, it will select the worthy candidate from one of the five worlds, and can grant her one wish. However, it is eventually revealed that the true purpose of the Platinum Princess is to quell the immense power of the Tiara. She does this through the strength of her heart, and her wish.

Also those candidates not chosen by the Eternal Tiara will simply vanish. Then the Tiara will disappear, allowing history to repeat itself once the Tiara is found and reassembled again.