A first-year junior-high school student and the son of the renowned Yotsuba family. Born a defective magician with very weak magical powers, he is treated like a servant and instructed to be Miyuki's guardian. As he rarely shows his emotions, no one can tell if he is dissatisfied with the role he has been given. Though lacking talent in magic, he excels in hand-to-hand combat, and was able to defeat military combat magicians at the tender age of thirteen.

A first-year junior-high student and Tatsuya's younger sister. She is next in line to be the head of the Yotsuba family, and unlike Tatsuya, possesses exceptional magic powers. She is fair and beautiful, with skin as white as snow and hair as black as night. Because of this, her friends call her “Ice Queen,” a nickname she is not particularly fond of. While Miyuki holds great magic potential, she hasn't received the same combat training that Tatsuya has, making her less effective in battle.

Twin sister of Maya Shiba, the current head of the Yotsuba family. A powerful magician known as the “Mistress of the Lethe,” she excels at Sensory Interference Magic. Her excessive use of this power in her youth has had profoundly negative effects on her health, and she remains very sickly. Though she is Tatsuya and Miyuki's biological mother, she treats Tatsuya coldly because of his lack of magical powers. She encourages Miyuki to treat Tatsuya like a servant.

A first generation “Sakura” series Augmented Magician who has been genetically modified to have greater magical capacity. At thirty years old, she specializes in magic that offers protection from all types of objects and heat, making her one of the top defensive magicians in Japan. As Miyuki's guardian, Honami both protects Miyuki and tends to her daily needs. She looks after Tatsuya and Miyuki as if they were her younger siblings.