Аяка Татибана

Рэйдзи's older sister and Харуки's daughter. She killed herself using Рэйдзи's magical device, in order to deprive her killer of satisfaction from the process. Despite the fact that the device had already made a contract with Рэйдзи, she was also able to make a contract with it, so Рэйдзи and Аяка share the same life points. She was born with a psychopathic disorder and is obsessed with her brother. Despite this, she is one of the top students in the school.