Race: Human
Height: 160 cm (5'3") (Catastrophe), 165 cm (5'5") (Vampire Reign)
Affiliation: Order of the Imperial Moon, Japanese Imperial Demon Army, Guren Ichinose's Aides
Section: Moon Demon Company, Guren Squad
Rank: Second Lieutenant

She is a second lieutenant of the Japanese Imperial Demon Army and a member of Guren's squad in the Moon Demon Company. While serving as a member of the Moon Demon Company, she is also an Army instructor for the training classes. Sayuri belongs to a retainer house that serves the Ichinoses. Sayuri is shown to be quite perceptive at times, observing how Yuu and his friends are much stronger than she is, when she was 16.

She had a crush on Guren and was his emotional support.