Keiko Numata

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

Appearance
She appears as old woman with short brown hair and brown eyes. She wears a white t-shirt and a yellow apron.

Personality
Keiko was introduced as a kind, gentle, and warm-hearted grandmother. But later on she was revealed to be an insane, psychopathic murderer.

Chikibi mentioned in the last episode that she and Kensaku where emotionally depressed about Ikuo's death. This may have lead Keiko to become insane in the last two episodes.

Plot
Keiko was first seen in Episode 10, when she and Kensaku welcome part of Class 3-3 who came at the Yomiyama Shrine to pray for their safeness, hoping that this action would stop the calamity. The class was accommodated at her restaurant-pension.

In Episode 11, she was revealed to be an insane psychopath. After Yuuya Mochizuki and Naoya Teshigawara found her in a room with a bloody knife, she attempted to kill them. In the process, Yuuya pushed her away from Naoya, causing her to drop her knife and wound the latter's leg. She continues after the two down the hallway. Keiko also killed her husband in a very brutal way and started a fire in the dining room prior to this. After Mochizuki and Naoya escapes from Keiko, he opens an emergency door and Keiko was inside waiting to kill them. The reasons for her insane actions remain a mystery. Though Ikou's death may have affected her greatly to drive her to insanity.

In Episode 12, when Mochizuki and Teshigawara escape by the window, she grabbed Mochizuki's leg. Teshigawara grabbed Mochizuki and pulled both of them out of the window. She grabbed Teshigawara and tried to kill him, but was stopped by Chibiki who proceeded to kill her. Near the end of the episode, Chibiki mentioned that they were Takabayashi's maternal grandparents, and they were emotionally depressed about his death.

Gallery
Main article: Keiko Numata/Image Gallery 

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, then proceeded to commit suicide by biting off her tongue. The reason for this wasn't revealed in the original novel and still remains unknown. In the anime, her bodycount is significantly lower (apparently limited to just her husband), though not for want of trying as she was hunting Yuuya and Naoya from the second half of episode 11 to the first half of episode 12.
 * Her first name, Keiko means "blessed child;" ironic, since she killed 5 innocent students, her husband, and then committed suicide.
 * While everyone else is focused on Izumi and Mei's confrontation at dinner, there are two scenes showing Keiko preparing to murder her husband and burn the inn to the ground.