Aya Mikage (御景 妖 Mikage Aya?) is a cute high-school girl and the protagonist at the beginning of the story who discovers she is a descendant of a tennyo named "Ceres" and is Ceres' latest medium for existence. The Mikage family takes this as a threat and continuously tries to take Aya's life. Her father is killed attempting to protect her. Her mother is forced into a coma for the majority of the series. While Aya is initially horrified that her life has been turned upside down, she is determined to right the past doings of her family and recover Ceres' hagoromo so that her family will no longer suffer in fear of her. As the series progresses, she falls in love with Toya and they conceive an unnamed child together. In the following sequel Episode of Miku, it is revealed that their child is a girl named Miku. Three years later, they have a son named Aki, who is the reincarnation of her late brother.

Aya was a perfectly happy and bright girl until the her sixteenth birthday when she and her twin brother, Aki are brought to a nightmarish birthday party that they'll never forget. When it was discovered that she had a tennyo named Ceres inside of her, the Mikage family sought out to destroy her. Even as the story changes, Aya is forced to run away from her once beloved twin brother who is now possessed by her obsessive ancestor. Aya is strong willed girl and is a bit athletic.