Nurse at Ozaki Clinic. She has a dog named Taro. Tohru has a crush on her.
She used to have a boyfriend, who disliked the isolated Sotoba village, and offered to marry her and bring her to the city. Ritsuko refused, as she couldn't leave the place where she grew up and her family.
Later, she also gets bitten, dies, then revives as a Shiki. However, she refuses to drink human's blood to live. For that, she slowly starts dying, while Tatsumi puts her in a cell with her best friend. Tohru begs her to bite her friend and survive, and seeing that Ritsuko refuses to kill her friend and prefers to die, he threatens her.