The Grudge film series features a large cast of characters mainly created by screenwriter Stephen Susco and Takashi Shimizu. The film series focuses on people affected by a deadly curse that spreads like a virus and manifests itself in various ways, such as turning people homicidal or people being haunted, ultimately leading to their demise, if they come in contact with the curse in any way.
All films in the series feature different protagonists, with the first being Karen Davis played by Sarah Michelle Gellar. The protagonist of the second installment and Karen's younger sister Aubrey was played by Amber Tamblyn, while the protagonist of The Grudge 3, Lisa, was portrayed by Johanna Braddy.
The Ghosts is the only characters that appeared in the all three The Grudge films.
Kayako Saeki portrayed by (Takako Fuji and Aiko Horiuchi) is the primary antagonist of The Grudge series, in life, an ordinary housewife, married to Takeo Saeki and mother of a little boy called Toshio. When she was a child, her mother performed unorthodox exorcisms, and passed her clients' curses to her instead of herself. Kayako and Toshio were later killed in a fit of rage by Takeo after he found her journal and discovered that she had feelings for an American man named Peter. Becoming an Onryō after her death, she now haunts the house, along with that of her husband, son, and her son's pet cat, Mar. A throaty, rattling noise usually comes out of her mouth.
Toshio portrayed by (Yuya Ozeki, Ohga Tanaka and Shimba Tsuchiya) was the son of Kayako and Takeo. In life, he enjoyed drawing and owned a cat. After he witnesses the death of his mother at the hands of his father, Takeo drowned Toshio in the bathtub, before killing his son's pet cat. Now Toshio's cursed spirit inhabits the house, along with the spirits of his parents and cat. He usually just haunts people, but there are times in which he has killed. He makes a meowing noise.
Takeo Saeki (portrayed by Takashi Matsuyama) is the husband of Kayako. Takeo finds Kayako's personal diary entries, several of which detail her love obsession with Peter Kirk. As a result, he murders her and Toshio in a fit of jealousy. Kayako hangs him by using her hair like a noose. He too, returns as a ghost but he doesn't have a special ghost form like Kayako and Toshio. He was not physically seen in The Grudge 3 except through archive footage.