Kanoko Saimori is the second wife of Shinichi Saimori, the mother of Kaya Saimori, and the stepmother of the story's protagonist, Miyo Saimori. Her background is rooted in a long-standing personal grievance. Before Shinichi married Miyo’s biological mother, Sumi Usuba, Kanoko was Shinichi’s lover. Their relationship was ended by an arranged marriage designed to improve the Saimori family's bloodline through Sumi’s supernatural abilities. After Sumi’s death, Kanoko finally married Shinichi, but her deep resentment toward Sumi for having been chosen over her never faded. She transfers this hatred directly onto Miyo, seeing her stepdaughter as a living reminder of the woman who she believes stole the life she deserved.

Kanoko’s personality is defined by her bitterness, cunning, and a complete refusal to take responsibility for her own misfortunes. She is a manipulative and cruel woman who presents a refined and elegant exterior in public but harbors a spiteful nature at home. Her sense of self-worth is entirely tied to her status as the lady of the Saimori household, and she feels deeply threatened by any connection to Sumi. She consistently blames Miyo for every problem that arises, no matter how unrelated, and shows no compassion or remorse for her actions. This cruelty is not born from love for her biological daughter, either; she raises Kaya to be competitive and superior to Miyo not out of genuine maternal care, but to fuel her own pride and desire for validation.

Within the story, Kanoko serves as the primary source of Miyo’s years of torment. She is relentless in her abuse, systematically stripping Miyo of her mother’s belongings, forcing her to live as a servant, and subjecting her to constant verbal, emotional, and physical violence. Her motivation is a toxic combination of jealousy towards Sumi and an obsession with maintaining her position. When Miyo is sent away to marry Kiyoka Kudo, Kanoko initially believes she is finally rid of her burden. However, upon learning that the marriage is successful rather than a failure, her hatred intensifies. Driven by this obsession, she teams up with her daughter and an outside ally to sabotage Miyo’s engagement, going so far as to violently imprison her stepdaughter in a storehouse.

Key relationships demonstrate her destructive nature. With her husband Shinichi, she holds a lingering grudge, as she was not his first choice, and he largely defers to her authority, enabling her abuse. Her relationship with her stepdaughter, Miyo, is one of pure contempt. Her treatment of her own daughter, Kaya, is also toxic; she pushes Kaya to be superior, but this is to satisfy her own ambitions rather than out of love, creating a strained and conditional affection based on performance and status. She also fired a maid, Hana, simply for showing kindness and protecting Miyo.

Kanoko’s development, or rather her lack thereof, is central to her character arc. She experiences a significant downfall after Kiyoka discovers the extent of her abuse and the Saimori family home is destroyed in a fire. Her status, wealth, and position are completely stripped away. She and Shinichi are exiled to a distant, impoverished home in the countryside, while Kaya is sent away to serve a strict family as a form of karmic punishment. Despite this complete ruin, Kanoko never apologizes or changes her views, continuing to blame Miyo for everything that went wrong and maintaining her victim mentality to the very end. Regarding notable abilities, Kanoko is explicitly described as coming from an ordinary family with no supernatural powers, making her one of the few characters in the story without any magical Gift or Spirit-Sight.