Professor Nobuyuki Kazaya is Mana's father and Yoshihiko's stepbrother. He is also Yukina and Tsugami's college professor. Dead prior to the series beginning, he is always depicted in Mana's flashbacks as a loving father, warning her not to tell anyone about her supernatural powers. However, he is actually a very ambitious man, desiring to prove to his stepbrother that he could create a super-human. Obsessed with Yukina's supernatural powers, he conducts a series of experiments on her with Sawaki's aid. This eventually leads to his accidental death by the hands of Yukina - his death was on the same day as Mana's birthday.