The game begins with Yui selecting one of the vampires instead of interacting with them simultaneously until it branches off into specific routes, like most visual novels. Because of this set-up, the only scene which is repeated throughout each character's route is the prologue. Otherwise, there are a total of 30 unique chapters for each character, with these 30 being split into three groups: Dark, followed by Maniac, and finally Ecstasy. An additional three chapters, known as "Heaven" scenarios, act as epilogues to the main story and can only be unlocked when all correct choices are selected. Chapters up to 7 in each group have only one correct choice. Chapters 7 and onward feature two choices that work toward unlocking different endings. End 01 can only be unlocked when all masochistic choices (indicated by an M) are selected, and End 02 is unlocked by selecting all sadistic choices (indicated by an S). Unlock End 03 by mixing these choices.
The following are the characters who can be chosen. Click on their names to see their walkthroughs.
- Ayato: The oldest of the Sakamaki triplets. Was raised by his mother, Cordelia, to be the best at everything, resulting in his self-absorbed and competitive nature. Refers to himself as "ore-sama" (a conceited way of saying "I") and refers to Yui as "Chichinashi" (literally meaning "Breastless").
- Kanato: The middle child of the Sakamaki triplets who has a childish attachment to his teddy bear, "Teddy", and a love of sweets.
- Laito: The youngest of the Sakamaki triplets who Yui knows as the pervert. He enjoys sexually harassing Yui and calls her "Bitch-chan".
- Shuu: The oldest of the Sakamaki brothers who is always tired, despite being seen sleeping much of the time. He is also fond of music, and would much rather listen to it than any one of his brothers.
- Reiji: The younger brother of Shuu and half-brother to the other Sakamakis. Acts as the head of the house due to Shuu's lazy indifference, though this sometimes gives him the appearance of a butler.
- Subaru: The youngest of the Sakamaki brothers and the only son of Christa. Constantly gets into fights at school and shows his anger by destroying walls in the mansion, much to Reiji's annoyance.