Kiyoko Shimatani is a supporting character in Majin Bone, recognized as the mother of Saho Shimatani, who is a childhood friend of the protagonist, Shougo Ryuujin. In terms of appearance, she is depicted as an adult female with brown eyes and short brown hair that reaches her neck. Her role in the story is primarily defined by her familial relationship with her daughter. After the Shimatani family home is destroyed by the Dark Bone, Kiyoko and her daughter are taken in and cared for at Shougo's house.

Kiyoko's personality and motivations are largely revealed through her interactions with Saho, specifically concerning her daughter's future. She holds a traditional and somewhat skeptical view regarding Saho's aspirations. When Saho expresses a strong desire to study in the geology department, a field that fascinates her, Kiyoko questions the practicality of this choice. Her notable line, questioning what her daughter would do going to the geology department as a woman, highlights the central conflict in their relationship. This dynamic positions Kiyoko as an obstacle to Saho's dreams, creating tension between a parent's conventional expectations and a child's individual passions. The narrative does not provide extensive detail on her personal development or any unique abilities, as her significance is tied to grounding the story in domestic realities and shaping the challenges Saho faces at home.