Sadako Yamamura
is the protagonist of the fifth novel of the series, "S". He is the eldest son of Mitsuo, a forensics doctor and protagonist of the novel "Spiral". Takanori once died drowned that led to Mitsuo becoming almost suicidal. As part of the agreement to help Sadako spread the Ring virus, she promises Mitsuo that she will resurrect Takanori through her womb. Fast forward to twenty five years later, the 28-year-old Takanori is now an image processing specialist who works at a CG company. He is also in a relationship with Akane Maruyama, who is pregnant with his child. After being handed a USB drive by his boss, he notices a video of a man named Seiji Kashiwada who killed himself. His investigations suck him into the cases that his father once delved into, revolving around the ring virus and Sadako Yamamura, the person responsible for his means to live. Takanori also finds out that Akane is related to the case as much as he is, being the daughter of Ryuji Takayama and a Sadako clone. Eventually, regardless of the situations they went through, the couple make up their minds to continue living together.