Ciel is a major heroine in Tsukihime, a visual novel by Type-Moon. She is a disciplined and highly capable member of the Church's Burial Agency, sent to investigate supernatural incidents in Misaki Town. Publicly, she appears calm, polite, and studious, but she is also a formidable fighter with strong combat skills and unusual resilience. In the story, she serves as both an ally and a route heroine, playing a key role in uncovering the mysteries surrounding Arcueid, vampires, and the hidden dangers of the setting.