Kohina Ichimatsu is an elementary school girl living entirely alone in a large shrine-like house with no parents or guardians to care for her. The circumstances of her solitude have led her to develop a deep psychological defense mechanism: she insists that she is a living doll created by state-of-the-art bio-technology, and therefore incapable of feeling human emotions such as loneliness, sadness, or joy. This claim defines her entire worldview and behavior. Her primary motivation is maintaining this self-image while seeking the basic comfort and stability she lacks, which manifests in her obsessive reliance on instant cup noodles for every meal and her desire to be left undisturbed.

In personality, Kohina consistently presents an emotionless facade, speaking in a flat monotone and rarely changing her expression. She struggles immensely to produce a genuine smile, an action that her face seems physically unable to perform normally. Despite her cold demeanor, she possesses a mischievous and dark sense of humor, frequently pranking the supernatural beings in her life, such as setting the immortal Inugami on fire for bothering her or teasing Kokkuri-san about his age. She is notably lazy, dislikes studying and doing homework, and is not above using trickery or her surprising physical strength to get out of responsibilities. Beneath this exterior, she is deeply lonely and afraid of being abandoned again, and she genuinely cares for those who become her guardians, even if she refuses to admit it outright.

Kohina is the protagonist of the story, and her role is established when she summons the fox spirit Kokkuri-san by playing the Kokkuri game by herself. Her home gradually becomes a gathering place for various mischievous yokai. Her central relationship is with Kokkuri-san, who takes it upon himself to become her strict and protective guardian, acting as a motherly figure who tries to teach her to eat healthily and express emotions. Inugami, a dog spirit, is obsessively devoted to her and declares his intention to make her his bride, a role she flatly rejects, treating him as a pet instead. Shigaraki, a tanuki spirit, is a lazy gambler and schemer whom Kohina openly scorns, but she tolerates his presence as part of her strange new family.

Throughout the series, Kohina experiences subtle but meaningful development. While she never entirely drops her doll persona, her actions increasingly betray a growing attachment to the spirits and a slow struggle to connect with her human peers, such as her shy classmate Jimeko. She begins to show moments of vulnerability and genuine care. Her notable abilities include immense physical strength that allows her to casually overpower opponents several times her size, including the spirits themselves, as well as the inherent spiritual sensitivity to see, summon, and interact with the yokai world that surrounds her.