Kiyoko Onodera (小野寺キヨコ, Onodera Kiyoko) is the daughter of Mayu.
Kiyoko is a short, elderly woman. She has presumably gray hair cut into a short bob. She is often depicted with her eyes closed, but her eyes are darkly colored and she uses dark, thick rimmed reading glasses. She is seen wearing slippers, a flower-patterned dress, and a dark-colored cap. She also wears the metal chain from her father's pocket watch as a bracelet. On the same arm, she has a burn scar imprinted by the chain, running from her palm to the back of her wrist.
Kiyoko has a gentle personality. For a long time she carried guilt over the death of her mother, thinking she was a burden to her the whole time they were together.
When Kiyoko was a young child, her father left his family to serve in the war. He gave Mayu his pocket watch, telling her to think of it as him. Kiyoko sobbed heavily, begging him not to leave. As the war progressed, Kiyoko seemed to hold on to the pocket watch as an object of comfort.
At some point, Mayu and Kiyoko were trapped on a burning bridge. Kiyoko held onto the chain of the pocket watch, which broke when Mayu threw her off the bridge into the water below to save her. Kiyoko thought that at the time, Mayu had shouted at her to go away. She felt guilt over this moment, thinking that she had always been a useless burden on her mother. It is implied that she has had nightmares of this event throughout her life.
Kiyoko lived on to have a child, who married her current daughter-in-law, Harumi.
Kiyoko prays to Tenjin that she may return her bracelet to its rightful owner. Tenjin has mistakenly overlooked it for some time before he finally notices it and passes the wish to Yato, saying that it's something only he can do. When they meet Kiyoko, she mistakes Yato for Tenjin, much to his grief. Before she can begin explaining her wish, she breaks into a coughing fit, which worries the three of them. Kiyoko goes on to explain that the bracelet really isn't something she should be holding on to, since it was given to her by someone long ago. Her daughter-in-law enters the room and adds that the bracelet is Kiyoko's last memento from her mother who passed away during the war. Yato then realizes why Tenjin said this was a wish that only Yato could grant.
Later that night, Kiyoko lies in bed, coughing as smoke enters the room. She dreams of her past history with her father and mother. Meanwhile, Hiyori, Yukine, and Yato enter her bedroom, and the latter two attempt to cut down the phantom which has been plaguing Kiyoko. However, since it has taken the form of intangible smoke, it simply re-coalesces within the room whenever they try to cut it. The phantom also produces a fire, but Yato refuses to destroy the chain even when urged to. Since the fire can't be put out with water, Yukine douses it using a song. The phantom then begins to reveal itself, taking a ghostly form resembling Mayu as she pushes Kiyoko off the bridge. Yato and Yukine cut it down, and Kiyoko's dream ends differently than usual: This time, Mayu yells that she must live on for both of them.
Kiyoko and Yato visit Tenjin's shrine together, and she wonders out loud whether her mother had actually shouted "Live!" that day on the bridge. Yato reminds her that Mayu had continued taking care of Kiyoko, despite the hardship of caring for a child during a war; he asks her what Kiyoko could remember of her mother. Kiyoko recalls that her mother had only ever wished kind things for her, including for her to have a long, healthy life.
Kiyoko falls out of her wheelchair, and she is helped by Mayu. She cries, recognizing her mother's face, voice, and gentle concern for her well-being. She thanks Mayu and returns the bracelet to her. Harumi then helped her back into her wheelchair, and they leave together. Mayu attempts to call after them, thinking Kiyoko had forgotten her bracelet, but Tenjin and Yato urge her to keep it.