Chidori Kuruma is a sixteen-year-old high school student who, despite her age, possesses a physical appearance that makes her look much younger, often mistaken for an elementary school child. She has light brown hair typically styled in pigtails with naturally curly ends. Chidori is a C-Genomer, meaning she is a descendant of a celestial being, or tennyo, and carries the mixed blood of humans and these heavenly maidens. This heritage grants her the ability to transform at will into a more mature and powerful form. In this transformed state, her appearance changes drastically: her pigtails become long and dark blue, her eyes turn a deep gold, and she grows significantly taller, resembling a fully grown woman rather than a young girl.

Her cheerful and seemingly child-like exterior masks a deep inner strength and a fierce protective nature, primarily directed toward her younger brother, Shouta. She is described as having a hyper-cheerful shojo exterior that belies a profound inner turmoil and dark secrets of which even she is initially unaware. The most important person in her life is Shouta, who was left paralyzed after their parents died in a car accident while saving their children. Her primary motivation throughout the story is her unwavering devotion to her brother, particularly to fulfill his lifelong dream of flying. This wish drives her to seek out Aya Mikage and her friends, asking the celestial maiden Ceres to take Shouta into the sky.

Chidori enters the central narrative by traveling to Tokyo to blackmail or coerce Aya and her companions into helping her brother. Her actions soon reveal that she and Shouta have a strange and dangerous connection to the nefarious Mikage family and their secretive C-Project, which seeks to harness the powers of celestial maidens. This connection leads to both Chidori and Shouta being kidnapped by the agents of the Mikage conglomerate. During a rescue attempt, as the group tries to escape, a guard attempts to shoot Yuhi Aogiri. In a selfless and decisive act of love, Chidori jumps in front of the bullet to protect him. While dying from her wound, she makes a final, incomplete attempt to confess her romantic feelings to Yuhi, a man she had quietly fallen in love with, but she passes away before she can finish her sentence. Her death serves as a tragic end to her personal story, having sacrificed her life in a final act of love and protection, not for her brother but for the one she loved.

Chidori is also a notable figure because, unlike the protagonist Aya who struggles with the dual personality of Ceres, Chidori can transform into her celestial maiden form without any apparent effort or loss of self. This indicates a different, more stable relationship with her inherited powers compared to other C-Genomers. She is also identified as a specific type of celestial descendant, a Pallas type A, which makes her a target for those seeking to restore a celestial robe known as the Hagoromo. Her birthday is March 2nd, and her name is believed to be partially derived from the word "chibi," which means small or tiny, a fitting reference to her youthful appearance.