Shimizu Megumi's childhood friend, though the sentiment is one-sided on her part, as Megumi is disgusted by the Sotoba villagers in general and doesn't think any more highly of Kaori. Later, she and her brother Akira becomes friend with Natsuno and aids him in the investigation about the Shikis.
Kaori and Akira are the first ones to notice Natsuno has been bitten by a Shiki and tries to warn his father. However, Mr. Yuuki disregards their advices, which eventually leads to Natsuno's death at Tohru's hands. Later, when Megumi gets wind of Kaori's increasing intimacy with Natsuno, she attacks Kaori's father and turns him into a Shiki. Kaori's father starts targeting his family and when he attacks Kaori, she snaps and beats him to death, while Natsuno watches her outside the house, ready to protect her if she needs to. When Natsuno appears to her, she thinks he is also a bad shiki and faints, while Natsuno catches her in his arms and smiles satisfied to see that Kaori has become brave and never stopped fighting for her survival.