Kaname Chidori serves as a colleague and supervisor to Koshiro at the marriage agency where he works. She is portrayed as an outgoing, friendly, and often joking individual who works closely with him. However, beneath this amiable exterior, she is also level-headed and represents a grounded, realistic perspective within the story.

Throughout the narrative, Kaname functions as a moral compass and a voice of societal norms, particularly concerning the taboo relationship developing between Koshiro and his younger sister, Nanoka. She is observant and begins to notice Koshiro and Nanoka spending time together, eventually deducing the true nature of their connection. Unlike a potential love interest for Koshiro who is underwritten and serves only as a plot device, Kaname is a more substantial figure who asks the difficult questions that the audience would likely have, enhancing the story's realism.

Her primary motivation is not romantic but stems from a sense of moral obligation and concern. She represents the strong societal view that disapproves of such a relationship, particularly given the significant age difference and the familial bond. As the series progresses, Kaname transitions from a casual friend and co-worker to a more confrontational figure. In the latter third of the story, she actively tries to intervene, confronting Koshiro about his situation, accusing him of perversion when she understands the truth, and attempting to make Nanoka leave. Her actions provide a critical external perspective on the central conflict, forcing both Koshiro and the audience to confront the painful reality and moral implications of his choices.