Sadako Yamamura
Upon further research of the "Ring" case, Takanori realizes that he has met Kashiwada years ago, but he was known as Ryuji Takayama back then. Connecting the dots between the physical similarities of Kashiwada's victims, Kihara theorizes that the victims were all clones of Sadako Yamamura, originator of the ring virus. It is possible that Kashiwada is hunting Sadako clones and, if he continues to hunt Akane, means that she is "also" a Sadako clone. During the premiere of Studio Oz's latest film, Takanori learns that Sakata's maiden name is Niimura. Requesting his friend to hack into her emails, Takanori connects to the emails of Hiroyuki, who is revealed to be Sakata's son. Hiroyuki keeps photos of the girls Kashiwada supposedly murdered, plus Akane's. Takanori finally realizes that Kashiwada had been framed and Hiroyuki was the real serial killer.