Age: 17
Birth date: September 7
Birthplace: Tokyo
Bloodtype: A
Sayo Hirasaka is a second year student at Sakurazuka High, and member of the Gardening Club. In the anime, she is introduced in a round-about way. She is seen with her parents during the incident with Ryouichi Karasu—the demon crow destroys the highway the Hirasaka family is driving on, and smashes their car. It is assumed the innocent Sayo is killed in the crash, much to Tatsuma Hiyuu's grief.
Sayo's history is slightly different in the original video game, but she is still used the same. She is also a descendant of Hirasaka from the prequel game Tokyo Majin Gakuen: Gehouchou.
(Source: Wikipedia, original video game data)