Keiko Numata

Keiko Numata is Ikuo Takabayashi's grandmother and Kensaku Numata's wife. She is the proprietor of Sakitani Kinenkan along with her husband.

Appearance
She is an old lady with greenish shot hair and green eyes. She wears a white T-shirt and a yellow apron.

Personality
Keiko seemed a kind, gentle and warm-hearted grandmother.

Plot
Keiko made her debut in the anime in episode 10 when she welcomes a part of the 9th Grade Class 3 who came at the Yomiyama Shinre to pray for their safeness, hoping that this action will stop the calamity along with Kensaku. The class accommodated at her restaurant-pension. In Episode 11, she was revealed to be the killer. After Mochizuki and Teshigawara found her in a room with bloody chopper, her attempts to kill them and during the process, her chopper drop and cut Teshigawara's leg. She continue to try to kill them and follow Mochizuki and Teshigawara along the hallway.

Trivia

 * In the original novel she killed Manabu Maejima,  Izumi Akazawa, Takako Sugiura, Junta Nakao, Shigeki Yonemura and her husband with a knife at Sakitani Kinenkan and then she suicide by bitting of tongue. The reason isn't revealed in the original novel and still remains unknown.
 * Her first name, Keiko mean "blessed child". It's ironically that her name mean "blessed child" while she killed 5 students, her husband and then suicide.