Kyō Kurumaru is a first-year student at Rettoran Academy of Magic and a member of the elite National Mage Training Specialized Course, known as the Magumi. He entered the program as the top-ranked student, having achieved the highest score on the entrance examination. He is the twin brother of Asuka Kurumaru, who is placed in the standard program. Kyō is described as a model student: upright, diligent, and handsome, and he commands a degree of respect among his peers that sets him apart within the first-year class. His demeanor is composed and refined, and he has a particular talent for brewing tea, which reflects his collected and polished nature.

Kyō's motivations are rooted in academic excellence and a sense of responsibility as a top student. He takes his role in the Magumi seriously and adheres to the structured, notebook-based magic system that the academy teaches. His personality contrasts sharply with that of his twin brother Asuka, who is free-spirited, fashion-focused, and enrolled in the general studies program. This difference in paths and temperament defines one of his key relationships. Kyō and Asuka represent two sides of the same family, with Kyō embodying discipline and tradition while Asuka pursues individuality and creative expression.

In the story, Kyō serves as a prominent figure within the Magumi, the selective track for students aiming to become certified national mages. His presence highlights the divide between the elite program and the standard class, where the main protagonists Kurumi Mirai and Yuzu Edel are placed. He does not undergo major personal transformation over the course of the series but functions as a steady, high-achieving counterpart to the unconventional methods of the standard class teacher, Minami Suzuki. His abilities are those expected of a top-ranked magic student: he is proficient in the official magical curriculum and demonstrates strong academic and practical performance in the formal magic system of the academy.