Voiced by: Taniyama Kishou (Drama CD) Age: 16 Birthday: July 25th Sign: Leo Height: 177cm Blood Type: O Favourite food: Carbonated drinks Pet-peeve: the dentist Ren is a first year student at St. Nazareth Academy who lives in S-hall, and is also the first guy to share his room with Hiyoki. At first, he is very hesitant about sharing a room with a girl, but he eventually warms up to her, showing a special interest in Hiyoki bordering between a sibling-esque affinity and romantic inclinations. Though he'll deny it fervently, he and Kuga seem to share a dysfunctional friendship. Incidentally, Ren and Cain have a bitter past together. Turns out he's Cain's brother.
Voiced by: Nakahara Mai (Drama CD) Birthday: June 18 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! In the end, Hiyoki realizes that the dream she had on her sixteenth birthday was just a fortune of what was destined to happen. Cain tries to steal her heart but he stops himself in the act. Kousetsu lied to her about the fake heart and tries to take Hiyoki's heart by force instead. Cain saves her and towards the end of the story, he confesses. Of course, she indirectly accepts.
Voiced by: Miki Shinichiro (Drama CD) Dorm manager of S-Hall. Currently the only person in the dorm aware of Hiyoki's situation.
Viewed as the undisputed school idol, she has a bit of a domineering personality.
Is "Yamada's personal deity", who aids her towards her goals (although she cannot be seen or heard by anyone) and represents her "pervert side". She takes on the appearance of a super deformed version of Yamada, save the mustache, and floats around on a pink cloud. This character also acts as a narrator at times recapping past events as well as occasionally breaking the fourth wall to address the audience.
Kyouka Kanejou is rich girl who moved from America to go to the same school as Yamada and Takeshi. She classifies herself as a perfectionist who can do everything, such as modeling, cooking, and sports. She becomes obssessed on becoming queen and beating Yamada, after losing to her in a pageant. She has an excessive brother complex, to a point where she wants her own brother to take her virginity away from her. She has a secret room with posters of him covering the walls, and will do absolutely anything at all costs to win his affection.
Takashi Kosuda is one of Yamada's classmates, and is the main subject of her lust throughout the series. Characterized as inept, sheepish and indecisive, he is also kind-hearted and often tries to look out for Yamada when he can. Takashi is initially taken by her advances, but that later turns into confusion and anxiety, due to the mixed signals between them, as well as his insecurities as a virgin. He lives at home with his older sister, who is a college student. One of his hobbies is photography. He is afraid of heights