TV-Series
Description
Chieko Sannomiya is the principal of the Seito Sannomiya Private School, having been appointed to the position a full decade before the events of the story begin. She is a woman of middle age or older, identifiable by her short brown or grey hair, purple eyes, and a pair of round glasses that contribute to her severe and intellectual appearance.

Her personality is defined by a profound and unwavering misandry. She carries herself with a conceited, formal, and aristocratic manner, fully convinced of the righteousness of her views. Chieko believes that men are inherently barbaric, aggressive, and unsuited for the nurturing profession of teaching. She champions an extreme form of feminism within her school, arguing that a woman's natural maternal instinct makes her the ideal educator, while men are the cause of conflict and violence. This belief system is the central motivation for her actions, which are seemingly irrational to outside observers.

Within the story, Chieko serves as the primary obstacle and antagonist. The main conflict is ignited when she flatly rejects the male protagonist, Hibiki Amawa, for a physical education teaching position solely because of his gender. Her rigid policies force Hibiki to disguise himself as a woman to gain employment at her school, creating the core premise of the series. Her role is to embody the institutional sexism that the protagonist must navigate and ultimately challenge.

Details regarding her personal relationships are sparse, but her interactions with others are almost entirely defined by her authority as principal and her contempt for men. She rules the school with an iron will and expects her female staff to fall in line with her philosophy. A significant, though understated, relationship is the one she has with her past. It is revealed that her extreme prejudice is not born in a vacuum but stems from a personal trauma: a man who abandoned her in her younger years. This man is hinted to have been a former gym teacher at the school, adding a layer of personal history to her professional discrimination. The landlady, Lulu Sanjo, seems to have knowledge of this incident from the past.

Despite being a seemingly static force of opposition, Chieko does undergo a degree of character development. The foundation of her ideology is cracked by the revelation of its personal origin, showing that her public policies are rooted in private pain rather than pure logic. Over the course of the series, the events and the example set by the disguised Hibiki begin to challenge her dogmatic views, forcing her to confront her deeply held prejudices. By the conclusion, her rigid worldviews are challenged, suggesting a potential for change.

Chieko possesses no supernatural or physical abilities. Her power is entirely derived from her institutional authority as the school's principal and the strength of her formidable, aristocratic will. Her notable ability lies in her capacity to enforce her personal ideology as school policy, exerting control over the faculty and the learning environment of the students under her care.