Aoko is a member of the Aozaki family. When she was young, Aoko's grandfather, the third generation head chose to raise Touko as his successor while Aoko lived with her parents. She is not afraid at all of her grandfather, who is labelled a monster, and only thinks of the great magus who created the final Magic as "a terrible old man who's lived for too long through questionable means". When she was sixteen years old, Aoko was suddenly named the successor to the Fifth Magic by her grandfather, and her sister Touko Aozaki, who was being trained as the successor until that point, was abandoned. Therefore, she originally had a very bad relationship with her sister. It was later revealed in Mahou Tsukai no Yoru, however, that the true target for Touko's anger was actually her grandfather who closed the Aozaki's path to the Root.