Karin Shinonome is a supporting character in the story and the younger sister of the protagonist, Yuzu Shinonome. She is chosen as the bride of Yota Kogetsu, a fox spirit, a position that has significantly shaped her life and personality. While sociable on the surface, Karin is fundamentally selfish and possesses a notably immature mentality and behavior for her age. Having been spoiled and doted upon by her parents and her fiancé Yota throughout her upbringing, she has developed a sense of entitlement and looks down on her older sister, Yuzu.

Karin’s motivations are primarily driven by jealousy and a desire to maintain her privileged position. She is displeased by the attention and status that Yuzu gains after becoming the bride of Reiya Kiryuin, the powerful heir to the ogre clan. Rather than being happy for her sister, this resentment leads her to actively conspire with Yota to sabotage Yuzu’s new relationship and separate the couple. This role as a rival establishes her as a primary source of conflict in the narrative, creating obstacles for the central romance. Her key relationships are defined by this dynamic. She is engaged to Yota Kogetsu, a fox spirit who is also unable to defy her or those around her, further enabling her spoiled nature. Her relationship with her sister Yuzu is one of antagonism, as she refuses to acknowledge her sister’s position and actively works against her happiness. Karin is portrayed as an obstacle whose selfish actions drive much of the interpersonal drama within the story. The character does not possess any notable supernatural abilities, with her influence stemming from her social position as a spirit’s bride and her manipulative behavior.