In "The Grudge 3," Kayako’s younger sister named Naoko is introduced although in "Ju-on" she was an only child ("Ju-on" novel). It is not revealed how close they were as sisters, and their mother seems to have only performed her exorcisms on Kayako. Naoko used to be terrified of her mother, but she seemed to learn how to become an Itako and she took her mother's equipment after she went into hiding. Naoko is aware of Kayako's death and knows she is an "Onryō". It is unknown who sent her the news clippings of Kayako's victims' deaths, it was most likely done by her co-workers who intended to embarrass her. When Naoko sees a clipping about young Jake's death, she decides to try to stop Kayako forever. When inside the apartment, Kayako frequently watches Naoko, however never tries to attack her. Kayako does not kill Naoko, but Takeo does, while possessing Max Morrison. Killed in rage when Takeo (Max) stabbed her through the back of her neck, Naoko was resurrected as a new "Onryō". It is most likely up to interpretation why Naoko became an Onryō herself. To save her sister's life, 8-year-old Rose Morrison drank Kayako's blood (which Naoko had obtained), containing Kayako inside her body.