Toshio Saeki Yamaga is a main character and one of the main antagonists in Ju-on: The Grudge.
Toshio is the cursed soul of a dead boy, and a child who was murdered by his father along with his mother Kayako Saeki. This led to them becoming evil spirits. His mother then killed his father in revenge leading to him becoming an evil spirit as well. The three of them then haunt and kill people.
In reboot series, Toshio Saeki have become onryo twice unlike original series and American adaptation: Toshio's reboot incarnation started his life as a boy named Toshio Yamaha who killed by his own family, with his violent death caused him to returned as an Onryo who responsible to kill those who entered the house. His reign of terror over the house come to halt upon founding the new owner of the house, Saeki couple, troubled with inability to conceive a child. Sensing Kayako's wish for a child, Toshio possessed her and caused her to be pregnant, with Toshio reincarnated into Toshio Saeki. His happy life comes to an end when he was killed by brokenhearted Takeo who betrayed by Kayako's love, resulting him returned as onryo again.
- Tsuyoshi Murakami
- Mizuho Tamura
- Taiji Suzuki
- Kazumi Tokunaga - supernaturaly suffocated to death on her bed.
- Aki Harase
- 3 unnamed boys
- Sukeru Takagi
- Jennifer Williams - supernaturaly suffocated to death on her bed.
- Trish Kimble
- Toshio is often characterized by his pitch-black eyes, pale skin, and the haunting meowing sounds he makes.
- Toshio's first appearance was in Takashi Shimizu's short movie "4444444444".
- Toshio was played by several child actors, being Ryôta Koyama in Ju-on: The Curse and Ju-on: The Curse 2, Yuya Ozeki in Ju-on: The Grudge, Ju-on: The Grudge 2, and The Grudge, Ohga Tanaka in The Grudge 2, Shimba Tsuchiya in The Grudge 3, Shūsei Uto in Ju-on: White Ghost and Ju-on: Black Ghost, Daiki Sawada in 4444444444, Kai Kobayashi in Ju-on: The Beginning of the End, and Ju-on: The Final, Rintaro Shibamoto in Sadako vs Kayako, and Garrett Masuda in Scary Movie 4.