Jiji is one of the residents of Amamizukan, the retro apartment building that serves as a sanctuary for a group of socially awkward otaku known as the Amars. She is a young woman with a pale complexion, glasses, and a choppy bob haircut, typically dressed in simple, unpretentious clothing like a pink button-up shirt, brown shorts, and a beige sweater.

Her personality is defined by a quiet and introverted nature, largely keeping to herself within the close-knit group. Among the Amars, each member has a specific obsession, and Jiji's is a pronounced attraction to older, mature men, sometimes referred to as elderly dandies. This fascination is a central and recurring trait, distinguishing her from her housemates who are obsessed with trains, jellyfish, or historical epics.

Despite her reserved demeanor, Jiji possesses a core of inner strength that becomes evident when the community faces pressure. When a redevelopment project threatens their home and the group launches a clothing brand called Jellyfish to raise funds, Jiji demonstrates significant initiative. She takes on the hard, often thankless role of product manager for the fledgling brand, a decision that showcases her willingness to step up for the good of the group. She actively educates herself for this responsibility, purchasing books on the subject to learn the necessary skills.

Jiji is also shown to be perceptive and not afraid to speak her mind when necessary. She pushes back against Kuranosuke, the stylish cross-dresser who becomes the group's mentor, when he becomes overly possessive of the protagonist, Tsukimi, reminding him that he must respect Tsukimi's right to make her own choices. Her technological savvy proves to be a notable ability; she quickly creates a blog to promote the Jellyfish brand, a crucial task for their modern business venture.

In terms of relationships, Jiji is a loyal member of the Amars and friends with all the other residents, including Banba, Mayaya, Chieko, and Tsukimi, though she does not have a single designated best friend. Her backstory is tied to her family; her younger brother was inadvertently the reason she chose to move out of her parents' home and into Amamizukan. A significant external relationship develops when she meets Keiichiro Koibuchi, a politician and the father of Kuranosuke, by chance at a café. Unaware of her connection to the resistance against the redevelopment plan he is involved with, he gives her advice, which helps inspire her to take on the product manager role.