Voiced by: Nakahara Mai (Drama CD)
Hiyoki Kozue is a new first year at St. Nazareth Academy. Hiyoki is a very kind and polite girl. She came to St. Nazareth to find the man with the platinum hair who stole her heart. She noticed that he had a tatoo of the schools crest on his chest and thought he must be at St. Nazareth. At first, without her heart, Hiyoki feels that she doesn't have the determination to do anything. The first important main character she meets is Cain Kumiode. Hiyoki accidentally bumps into him and falls to the ground. Where Cain glares at her and says "There's something disturbing about you..." Hiyoki ends up passing out because of her surprise and the fact that she doesn't have a heart.
She ends up waking up, an notices that her shirt is open. A strange man ends up appearing. Introducing himself as Nousu, the advisor of S-hall, which Hiyoki is currently at. Nousu tells Hiyoki how he noticed that she doesn't have a heart and tells her he gave her a temporary one. He warns Hiyoki that her "new" heart is very fragile and can cause her death if it over reacts. Nousu then tells her that S-hall is her new dorm, but they don't have a room for Hiyoki so she will have to bunk up with a new roommate every week until they have one open for her. Nousu takes Hiyoki to meet her roommates and she notices they are all guys!
Vova
