Shibata Mizuki is a student of First High School, and a Year 3 Magic Engineering Course student, joining the course at the beginning of her second year. During her first year at the school, she was a Course 2 student. She meets Tatsuya on her very first day at the school, where he infers that he should be wary of her "eyes". They later become friends and she is part of the same circle of friends as he is. Mizuki is described as a timid-looking girl who wears eyeglasses. In their era, it is rare for girls to wear glasses because a vision correction procedure is already widespread. Tatsuya correctly inferred that her glasses were to reduce her over-sensitivity to Psion energy, allowing her 'crystal eyes' to even perceive the hidden aura and the exact nature of spirits. She also has very large breasts and a curvaceous figure. Despite being a shy person, Mizuki is the one who loses her temper over the Course 1 students' rude actions during the first day of school, when the group persistently tried to get Miyuki to join them. She provoked Morisaki Shun, the one leading the group of Bloom students, almost resulting in a 'battle using magic' had Chiba Erika not interrupted. Mizuki is also seen as an innocent person, as she appears to take Tatsuya and Miyuki's romantic banter seriously, despite the former admitting that he's only joking around about it. It's also possible that Mizuki has feelings for Yoshida Mikihiko, through subtle hints. Mikihiko has admitted toward Tatsuya, while being unaware of it himself, that he holds special feelings toward Mizuki. Mizuki constantly wears glasses, due to her eyes being Over-sensitive to Spirit Particle Emission. She initially didn't understand what to do with this predicament. It is revealed that she has a special sight that Mikihiko calls Crystal Eyes. She initially didn't know what to do with this ability. However, Mizuki is a smart person and important events like the Nine Schools Competition and Visitor Arc show this, giving her the chance to use this ability to aid her friends and gather information.