Mizuho Miyanokouji is the main protagonist of the story, a polite and well‑mannered young man from a wealthy family. He is forced to transfer to an all‑girls Catholic boarding school because of his late grandfather’s will, and he must cross‑dress to attend. Fortunately, Mizuho has a naturally androgynous appearance, which makes the disguise believable to most of the other students. He uses his mother’s maiden name, Miyanokouji, to enroll; his actual surname is Kaburagi. Mizuho’s mother died from an illness when he was younger, and one of her last wishes was that he not be forced to cut his hair until he was old enough to decide for himself. He has kept his long hair ever since, believing it suits him.

As a child, Mizuho had very little self‑confidence and often depended on his childhood friend, Mariya Mikado, following her around and relying on her support. This shyness carried into his adolescence, though he becomes more comfortable as the story progresses. Despite his feminine attire, he continues to use masculine speech patterns in Japanese, such as referring to himself with the pronoun boku. He is constantly nervous about being discovered as a boy, but on his first day at the school he is warmly received and quickly becomes popular among the student body. He is eventually elected to the prestigious position of Elder, the highest honor a student can achieve.

Mizuho’s primary motivation is to honor his grandfather’s final request while keeping his true identity hidden. Over time, he reveals a deeply compassionate nature, going out of his way to help other students, such as Kana and Yukari, with their personal struggles. His key relationships include Mariya, who helps him adjust to school life and teaches him how to act like a girl; Shion, a classmate who discovers his secret early on but chooses to keep it and assist him; and Takako, the student council president who initially rivals him for the Elder position but later becomes a trusted advisor. The Kaburagi family has a long‑standing rivalry with the Itsukushima family, and Mizuho initially does not realize that Takako belongs to that rival house. Despite this, he does not view her as an enemy and genuinely enjoys her company, especially during their shared Japanese history class.

Mizuho grows from a timid, dependent child into a more confident and responsible young person who earns the respect and admiration of those around him. His defining traits are his kindness, his quiet determination, and his ability to navigate a difficult situation with grace, even while living in constant fear of exposure.