Queen Ercell
エルセル女王
Queen Ercell, in addition to being queen, is also the principal of the Princess Academy, and the keeper of the Eternal Tiara. She is in charge of finding the Platinum Princess candidates and guiding them through their tasks.
She clearly seems to recongize Gunbard by the gasp she makes when Yuice announces she is his daughter to Queen Ercell, but what connection Queen Ercell might have remains is kept somewhat mysterious for much of the series.