Kayako Saeki (佐伯 伽椰子, Saeki Kayako) is a fictional character and the main antagonist of the Ju-On and The Grudge horror franchises. Kayako's fictional history alternates slightly between continuities, but all depict her as the attractive but vengeful ghost of a woman killed by her husband, Takeo, along with their son Toshio, in a murder–suicide that happened after he came to believe she was having an affair. After the crime, the spirits of all three are bound to their family home, haunting and killing all who enter in the following years.
Saeki has been played by a number of actresses in films, including Takako Fuji in Katasumi (1998), Ju-On: The Curse, Ju-On: The Curse 2 (both 2000), Ju-On: The Grudge (2002), Ju-On: The Grudge 2 (2003), and the American remake films The Grudge (2004) and The Grudge 2 (2006), Misaki Saishō in Ju-On: The Beginning of the End (2014) and Ju-On: The Final Curse (2015), Kyōka Takizawa as a child in the American The Grudge 2, Aiko Horiuchi in the American The Grudge 3 (2009), Anna Moon in the American Tales from the Grudge (2006), and Junko Bailey in the American The Grudge: The Untold Chapter (2020).
The American adaptations expand the backstory of the character, with her only cameo appearance occurring in the 2020 film, where her "grudge" is transferred to other spirits. Saeki also appears in Kōji Shiraishi's 2016 crossover film Sadako vs. Kayako (portrayed by Runa Endō), alongside The Ring antagonist Sadako Yamamura.
