A second-year high school boy.
He is usually a jokester who loves girls. His grades are terrible, he's hopeless at sports, and he's on the verge of flunking out. He has a somewhat rough way of speaking, is selfish, and is a tsundere. A habitual offender of tardiness, leaving early, and skipping class, he appears to be a perverted and cowardly ordinary high schooler. However, when an incident occurs, he displays sharp observation and deductive skills. The gap from his usual self is extreme, and he never gives up on uncovering the truth. He likes you and prioritizes them above all else, but he can't be honest about his feelings.

The current head of the family. Calm and dignified, his thoughts are inscrutable. He will stop at nothing to protect his family. He knows the most secrets about the mansion and the family.

The beautiful and elegant wife of the family head. She appears gentle at first glance, but is highly intelligent and calculating. She harbors a secret she has never revealed to anyone in the family.

A free-spirited problem child. While he seems to distance himself from the family, he is actually independently investigating the family's past. A friend of Rei and you, he invited Rei to investigate the family.

A quiet and lovely girl who appears to be the most harmless member of the family. However, she seems to know something about a past incident that occurred in the mansion.

A detective familiar to Rei and you. He is usually the one who appears when an incident occurs. He provides information and assists Rei and you in solving cases. He is so lackadaisical it's hard to believe he's a real detective, but he tackles incidents with seriousness when they happen.