Aki is a Psycho Duelist who has extraordinary powers, which she blames the 'wretched mark', her Signer birthmark, for. She has the ability of making the effects of cards very real and her opponents take real physical damage. However, she does not want her identity known when she unleashes these powers, so she hides behind another identity of hers called the Black Rose Witch, since her ace monster is the Black Rose Dragon. The only person that seems to understand her best was Divine, who assisted her when she joined the Arcadia Movement, an organization of Psychic Duelists. However, after meeting Yusei in the Fortune Cup, her outlook on life changes bit by bit.