Date of Birth: March 12
Blood type: B
Height: 156 cm
Weight: 43 kg
Hisui is an orphaned child brought to the Tohno Mansion at an early age. Hisui, and her sister Kohaku were brought to the house for the express purpose of aiding Makihisa Tohno, patriarch of the family, to overcome his demon blood through their abilities as "Synchronizers", or beings that enable the transfer of energy. This transfer of energy is performed by the exchange of bodily fluids, such as another drinking their blood, but it is strongest in the act of intercourse. Hisui, however, was never forced to utilize her abilities as a Synchronizer because of the pleas of Kohaku and instead found herself playing outside every day with Shiki and Akiha. Her childhood was pleasant, and even though she is not naturally an active person, upon seeing Shiki playing so energetically she did her best to keep up with him.
Voiced by: Yumi Kakazu (Japanese), Kate Higgins (English)