Queen Ercell

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, as well teaching other princesses and noble's daughters. She clearly recognized Gunbard by the gasp she made when Yucie announced she was his daughter to Ercell, but what connection Queen Ercell is kept somewhat mysterious for much of the series.

Later it's revealed Gunbard was actually Ercell's former lover many years ago. Gunbard went to gather the parts of the Eternal Tiara in all five worlds so that he becomes a knight would be able to marry Ercell, as he was just a commoner with a small patch of land, to his dismay, when he returned, Ercell had already accepted one of the proposals.

Personality
A calm and collected personality no matter the times.

Appearance
During her time with Gunbard, she lets her long hair untied.

Years later, she wears her current hairstyle.

Background
She was a Princess on the Kingdom. She has a relationship with Gunbard during their youth, but eventually married the future King, who had taking quite a liking to Ercell. She had refused his offers, until her father grew ill. Ercell had been convinced that finally marrying a suitor would give her father the strength to recover from his illness. So she eventually relented. After she accepted the marriage proposal. Her father did eventually recover. Though his left both Ercell and Gunbard secretly unhappy.

Before the conquest
She and Gunbard has a relationship, albeit secret from the Kingdom. She and Gunbard planned to build a simple house near Lord Drago's Lake and a forest, live simply and with Gunbard being a knight, marries her. So the lad decided to conquer the realms and procure the Eternal Tiara to do so. She initially resisted the thought of him gone, but she relented and gave him a magical sword, shield and set of armor, and in return, Gunbard gave her a ruby-studded ring and the promise that he will return successfully, and marry her if he was successful and becomes a noble in his feat.

Return
But her father has other plans. She was confronted by her father, who wanted to marry a Prince in a nearby Kingdom. She was depressed for days, looking at the ring. Until one day, she decided to move on, removing the ring and went on to marry the man her father wanted.

Later, Gunbard returned with the good news and the Tiara. But he was dismayed and broke when he saw her near the new King, and a different ring on her finger. He left the castle after the ceremony, she tried to chase, but stopped midway.

Present
Being the Queen, she focused on raising her son Arc, and managing the Kingdom, with her husband died years before the series. She also the headmaster of Princess Academy, a school for nobles and princesses of the land, where these young women are taught basic Royal duties and responsibilities.

She spotted Yucie trying to touch the Tiara, as she was alarmed with her trying to infiltrate the room. She explained why she does that, and was shocked upon her introduction. Later, she oversees the development of the Platinum Princess candidates.

Gunbard
Her former lover. Loved him so much, that she wanted to abdicate to be with her. But he has other plans, to be a noble (via completing the impossible feat of restoring the Eternal Tiara) and marry her. Many years later, she moved on and married the Prince her father wanted. Later, after Gunbard returned, she shows concern for him, but too late. Many years later, they treated each other like there is nothing between them, not even friends.

Prince Arrow/Arc
Her son with the King, she raised her son with care and love, but never overlooked his shenanigans.

Gunbard
Her former lover. After the conquest and the ugly truth, they had nothing to do with each other, even when Arc was cursed by Diabolos.

Trivia

 * It remains unknown whether or not Gunbard is the true father of her son, Prince Arrow.
 * Her relationship with the future King was treated as NTR, she chose the Prince over Gunbard.