Kiriko is a character who exists in two distinct forms within the story, serving as a crucial guide and protector for the protagonist, Mahito. In the mundane world of the rural estate where Mahito comes to live, Kiriko is first seen as one of the elderly maids who works in the household of his stepmother, Natsuko. In this guise, she is described as a sour-faced but devoted servant who, along with the other older women, fusses over Mahito after he sustains a self-inflicted injury to his head.

Her most significant role, however, unfolds in the fantastical other world that Mahito discovers. When Mahito descends into this strange realm, he is saved by a younger and immensely powerful version of Kiriko. This version is an adept fisherwoman who possesses a magic wand that can create fire, which she uses for both her work and her defense. She immediately takes charge, rescuing Mahito from attacking pelicans and navigating treacherous rock formations with him. Her abilities are crucial for survival, as she demonstrates when she catches and sells a giant fish to the Warawara, which are bubbly, spirit-like creatures preparing to be reborn in the world above.

Personality-wise, the younger Kiriko is firm, authoritative, and highly capable, embodying a blend of traditionally masculine and feminine traits. A semiotic analysis of her character reveals that she uses masculine linguistic features like specific pronouns and interjections, creating a strong and commanding speaking style, while also displaying feminine expressions and roles in certain situations. Visually, this androgyny is represented through her short hair, masculine clothing such as pants and boots, and assertive gestures, which together challenge stereotypical gender norms. Her role is fundamentally that of a mentor and a source of practical knowledge about the magical world, helping Mahito understand how its inhabitants, like the Warawara, function. She also aids in brokering a fragile peace between Mahito, the deceptive Grey Heron, and the desperate pelicans of that realm.

Her motivations are rooted in a sense of duty and protection. In the real world, she is a loyal servant to the family. In the other world, this devotion is translated into direct action, as she actively defends Mahito from threats and teaches him how to navigate the dangers he faces. Her key relationships are primarily with Mahito, whom she guides and protects, and with the Grey Heron, with whom she interacts as a pragmatic ally in the quest to find Natsuko. The narrative development of Kiriko comes full circle at the climax of the story. As the fantastical world begins to collapse, she reunites with the other main characters to escape. Later, when Mahito returns to the real world, the charm doll he has been carrying transforms the elderly maid back into her familiar form, linking the two versions of the character into one and suggesting that her powerful younger self is a true reflection of her inner spirit.