Chiho Sakura is a classmate of Hinata Kawamoto and a student at the same middle school. She is a bespectacled girl with a very introverted and timid personality, which makes her socially vulnerable. Chiho becomes the central figure in a severe bullying arc within the story. Her troubles begin after an act of genuine kindness: she gives half of her lunch to a male classmate, Yusuke Takahashi, who was unable to eat for personal reasons. Instead of being seen as a compassionate gesture, this act becomes a pretext for bullying, led by another student named Megumi Takagi. Driven by a combination of envy, jealousy, and a perverse interpretation of Chiho's motives, Takagi and her friends begin to torment Chiho. The harassment escalates to the point where Chiho refuses to attend school.

Her role in the overarching narrative is that of a catalyst for one of the story's most significant emotional turning points. As the victim of bullying, Chiho's suffering directly inspires her friend Hinata to stand up against the injustice. When Chiho is forced to transfer schools after her parents decide to pull her out of the environment, Hinata publicly confronts the bullies, an act of defiance that leads to Hinata herself becoming the new target of their cruelty. Despite the painful outcome, Hinata never regrets defending Chiho, an event that deeply impacts the protagonist, Rei Kiriyama. Even after moving, Chiho and Hinata maintain their close friendship by exchanging letters, which become a source of comfort and hope for both of them.

In terms of key relationships, Chiho is most closely connected to Hinata, who remains a loyal and protective friend. Her antagonistic relationship with Megumi Takagi defines the central conflict of her personal story. Following her transfer, Chiho moves to her father's house to receive care and recover from the trauma. The psychological damage she suffers is substantial, manifesting as post-traumatic stress disorder. She initially finds it difficult to even reply to Hinata's letters and freezes up or feels intense anxiety when she sees other girls her own age. Her development is shown as a slow and gradual process of healing. Through treatment and the peaceful environment of a ranch where she raises animals, she begins to improve. She eventually makes enough progress to meet Hinata in person, showing that she is learning to become more socially confident. No information is available about any notable abilities Chiho Sakura possesses.