Chiyo is a young girl working at Kuronekotei café, sharing a close friendship with the automata Haizakura. Born overseas, she returned to Japan with relatives after the Great War. Her appearance features brown hair styled in a small side ponytail with a distinctive ahoge, secured by a hairclip, and brown eyes. She typically wears a pink kimono patterned with yellow and white florals, a white apron, a yellow sash, white socks, and black sandals.

Lively, energetic, and strong-willed, Chiyo embodies notable vitality and a generally optimistic spirit. Her relationship with the automata Yugiri is especially deep, resembling sisters; Chiyo expresses profound affection and concern for Yugiri's well-being. This bond proves pivotal when Yugiri, under external control, briefly threatens Chiyo during a conflict, causing profound emotional distress for both.

During a large-scale mechanica assault orchestrated by Haikagura, Chiyo suffers a severe head injury after being attacked by frenzied machines alongside Haizakura and Yugiri. The injury causes significant blood loss and necessitates urgent medical care. She recovers under the supervision of Imperial Army personnel, coinciding with revelations about the origins of the Ouka and Kikka-class automata.

Beyond her personal story, Chiyo serves key narrative functions. She acts as an emotional anchor for Yugiri, whose temporary liberation from control occurs partly through Chiyo's influence. Furthermore, her injury catalyzes Haizakura's transformation by triggering the emergence of Ouka's consciousness. Her relationships with the café's automata collectively underscore themes of human-machine bonds in the postwar era.