A bright and social young man with reddish-brown and cream fur. He lives in an old detached house. He is a close friend of the protagonist; they joke around and visit each other's homes often.

A young but experienced wolf police officer. He has been independently investigating mysterious cases occurring in town for several years. Handling supernatural entities is effectively banned within the police force, but he questions this policy. Taciturn and honest. He does not boast about his sense of justice.

An entity of unknown origin that perfectly mimics the appearance, voice, expressions, and gestures of others. Its true form is a monster with unnaturally long limbs, black fur, and a distorted white face. It mimics the appearance and voice of the missing Sei to lure the protagonist to his house. While mimicking, there are no unnatural points in its appearance or behavior, making it impossible to see through with normal observation or conversation. The Echo can cancel or change its mimicry at will. Once its identity is revealed, it relentlessly pursues Guest, using the forms and voices of various people to psychologically corner them. It never uses brute force. Its purpose and thoughts are unknown. It is not even clear if it understands human emotions.