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.