Сіель

Ciel (whose real first name is Elesia) was a normal individual born in France to a French father and an Oriental mother. However, unlike those around her, Elesia had a high magic potential, and it was this rare characteristic which ultimately put Roa inside her as his 17th host body after his 16th host body was killed without having chosen his next host body. In the process, Ciel became a vampire and killed everyone in her village, the massacre only ended when Arcueid Brunestud arrived and killed her, fulfilling her duty of killing Roa whenever he reincarnates. However, unlike previous hosts, Ciel returned to life after Roa had moved on to a new host.

The secret Vatican agency known as the Burial Agency captured her, and over the course of a month she was killed repeatedly by the Church, only to rise again on every occasion, because as a host of Roa while Roa was also inhabiting another, it was impossible for her to permanently die until Roa was killed. Despite their usual views on sorcery, vampires, and the like, the Church decided to use her abilities as a member of the Burial Agency, her main desire and mission being the elimination of Roa to end her eternal existence.