Chieko is one of the resident sisters living in the Amamizukan apartment building, serving as the current manager of the property in her mother's absence. In her thirties, she is a dedicated otaku whose passions are centered on traditional Japanese culture, specifically the collection of Ichimatsu dolls and the crafting of miniature kimonos to dress them. Her deep knowledge extends to all aspects of kimono and yukata, making her the resident expert on traditional garments.

Chieko lives alongside the other otaku residents of Amamizukan, including the jellyfish-obsessed protagonist Tsukimi, the Chinese history enthusiast Mayaya, the train fanatic Banba, and the admirer of older men, Jiji. Together, they form a sisterhood that largely confines itself to the building, venturing out only when necessary, such as for their weekly grocery supply run. Like her fellow residents, Chieko is a recluse who is deeply uncomfortable with fashion and societal expectations, embodying the reclusive lifestyle of a NEET, though the residents would not readily admit to that label.

Chieko is consistently depicted wearing a kimono, a choice that sets her apart within the group. During a significant makeover sequence where the other sisters are given modern, stylish clothing to boost their confidence, Chieko is the only one whose appearance remains unchanged. Kuranosuke, the fashionable cross-dressing son of a politician who befriends the group, validates her traditional attire, explaining that a kimono is perfectly appropriate for a landlord's daughter. This moment underscores how her aesthetic, rooted in heritage and personal devotion to her craft, is recognized as a valid form of style in its own right. Her commitment to her interests represents a quiet form of resistance against the pressure to conform to mainstream beauty standards.

Chieko's role in the story is primarily as a supporting member of the Amamizukan community. Her home is the central gathering place for the sisters, and her position as the manager gives her a stake in the building's fate. A recurring plot point involves the threat of redevelopment to their beloved home, and Chieko's collection of antique dolls becomes a source of potential financial value in the struggle to save the building. Her motivations are closely tied to the preservation of her home and her lifestyle, which allows her unlimited time to dedicate to her doll-crafting hobby. While not the central protagonist, her steady presence and unique expertise are integral to the fabric of the story, providing a connection to traditional arts and a stable, if unconventional, anchor for the other eccentric residents.