| Kimiyoshi Aki|
|Portrayed By||Tani Ikuko|
Kimiyoshi Aki is a former resident of Hinamizawa, and part of the Kimiyoshi House, one of the Three Great Families of Hinamizawa. Because of her son-in law's job, she had to move from her home village along with her family. Even though she was against this decision, she had no choice due to her old age. Just like the other older Hinamizawan people, she strongly believes in Oyashiro-sama, in fact, she even made an altar for him after moving in to the Kimiyoshi family's new house. She always looks after Natsumi and is shown to be a rather easy-going and kind woman. In Onisarashi-hen, it was shown that despite her old age, she tries to do smaller jobs around the house, such as pulling out the weeds. In Someutsushi-hen, it was revealed that she is actually quite lonely, since the city where the Kimiyoshi family moved in doesn't have many older people. Because of this and her old age, she rarely leaves the house. While her rank in the Kimiyoshi Clan is unknown, she's probably closely related to Kimiyoshi Kiichirō, since her granddaughter, Natsumi, often attended the village meeting as a child. In Someutsushi-hen Aki and her family are almost instantly informed about the death of Tomitake Jirō and Takano Miyo, even though the case is being kept as a secret by the police.
After the Great Hinamizawa Disaster, she becomes paranoid to the curse of Oyashiro-sama and starts various rituals to "protect" the Kimiyoshi house from the curse, despite the other family members', especially Haruko's disapproval. At the beginning, these rituals only include praying to the altar of Oyashiro-sama, but as the story progresses, she starts to decorate the house with candles and various charms and later on she even drowns puppies in the bathtub in order to "protect the family from the curse". After hearing the relatives strange behavior from her mother, Natsumi in fear pushes away her grandmother who accidentally hits her head in the desk and dies. Aki's behavior is one of the main triggers of the Hinamizawa Syndrome in Natsumi and starts the events in Onisarashi-hen.
In Someutsushi-hen, her behavior after the Great Hinamizawa Disaster isn't as extreme as it was in Onisarashi-hen (she doesn't drown puppies this time), but her strong faith in Oyashiro-sama still causes conflicts in the Kimiyoshi family. Even though in this arc she isn't as radical as she was in Onisarashi-hen, she's still killed by Natsumi (who is already under the influence of the Hinamizawa Syndrome, due to various events in the arc) while praying at the altar.