In the Chess no Koma hierarchy is she who occupies the second place as the best in strenght and skill, but especially for her prestige.
Usually she makes out in the dark while she watches the matches of two people that seem to interest her very much: Snow and Dorothy from MÄR's group. She talks a lot with Phantom, who seems to know her very well.
Silent and observer, she long for something that will be discovered with the development of the story.
Her true name is Diana, and she's Dorothy's older sister and Snow's stepmother. As her sister, she's from Kaldea, the realm of witches and magic. After that she stole 798 ÄRMs from her country, she escaped and secretly formed the Chess no Koma. When she gave to Phantom the baptism of the Zombie Tattoo and Babbo, she let him become the Knight number one and the leader of the group. When Snow's mother, the queen of Lestava, died, the king, who was looking for a wife, fell in love with her because of her charm and the beautiful look, so that he decided to make her become his wife. At this point the woman become a loved and respected queen, particularly from Snow, who's fond of her. As the Chess no Kotma became a strong army, sometime before the begin of the war, Lestava's soldiers joined a new faction, the Cross Guards, whom Diana gave the ÄRMs (for example Monban Pierrot to Aran with whom he evoked Danna on MÄR Heaven) in order to protect her realm. But truly, this is just a part that she show to us of her behaviour. At the end of the war and at the death of the king, Diana completely changed her character, let prevailing her real ego: she wasn't the sweet queen that she was once, but a capricious woman thirst of power. What she desire were jewels, amusements, beautiful clothes... But being a queen, all these stuffs never fail to her, till one day, she doesn't know what to desire, and she decide to have MÄR Heaven. Obviously, the realm couldn't become of her own, but she must absolutely obtain it, so that at the end she could destroy it and stop her desire. So, both Aran and Snow, undestood which was her game, escaped from the castle in order to don't allow her to command them, especially Snow who serves to her plans because she's the princess of her realm (and afterwards she will be kidnapped by Magical Row, sent there by Diana). During the journey to Kaldea that do the MÄR team, Diana sends Phantom to destroy her realm only for finding an ÄRM. In the last part of the manga, she finally fights against her sister Dorothy, who with a stab will kill her. In her last words, freed from the King's influence, she will remember the good times when she made puppets for her little sister (Pinocchion has been made by her). She dies in Dorothy's arms, because in this way, she expiates her sins.