Keigo Narumi 29 years old Has a pleasant, calm personality. Highly observant and often notices small inconsistencies. He has known the master for a long time but is reluctant to talk about why. While cooperative with the investigation, he is also one of the suspects. He often acts with Guest, but he is not a fixed partner.

Renji Takamiya 28 years old The master's nephew. Strong-willed and short-tempered, he pushes back without flinching even when suspected. He was in conflict with the master over the inheritance and had an argument just before the incident. He is blunt and foul-mouthed, but surprisingly caring toward those he likes. Since he wears his heart on his sleeve, it is difficult to judge his true intentions based on anger or irritation alone.

Sota Mizuki 23 years old Bright and friendly, he naturally puts people at ease even in tense situations. He says he is an acquaintance of the master but won't reveal the details of their relationship. He has a period of time on the night of the incident that is difficult to explain. Though he seems honest, he is surprisingly good at lying and can be elusive at times.

Kei Shinomiya 32 years old A servant who has worked at this manor for many years. Unfriendly and composed. A man of few words, but his work is flawless. He knows the structure of the mansion and the master's habits better than anyone. Because he remains calm after the incident, he is easily suspected, but he does not defend himself more than necessary.

Mizuki Shiraishi 26 years old A gentle and elegant woman. She is polite and cooperative with Guest. She visited the manor at the master's invitation but refuses to reveal the reason. She hides secrets behind her soft demeanor. She is cautious but gradually shows her true feelings to those she trusts.