The "Forgetful Detective" who loses her memories of the day whenever she sleeps. She is characterized by her white hair and glasses. She possesses excellent observational and deductive skills and has great confidence in her memory as long as she is awake. Cases are basically solved within the same day. She is calm and moves at her own pace but is highly inquisitive. She forgets her memories with you every time she sleeps. She has notes written in permanent marker all over her body; she usually keeps them hidden, but she has a habit of checking them whenever she wakes up, starting every morning by understanding herself through the body notes as her memory resets. Even if she has no recent memories, she retains memories from before this condition started. However, when asked when that was, she replies, "That's a corporate secret."

Your younger sister. She is bright, hardworking, and cares for her brother. While exasperated by her brother's abnormal bad luck, she is always worried about him.

Your ex-girlfriend. You are still on speaking terms, but you both have a bit of lingering affection. She can't be honest and sometimes gets jealous.

A wealthy heiress. She is strong-willed and free-spirited but kind at heart. Her father has connections to organized crime, which sometimes gets her involved in incidents.

The detective agency receptionist and informant. Whenever the protagonist is treated like a culprit, this is the place he always contacts. He receives an explanation about Kyoko Okitegami here and is introduced to her. She has a wide network and excels at information gathering. She is aloof and hard to pin down, and is well-versed in underworld information.

A forensic doctor. She is calm and has a sharp eye for observation. She examines bodies and wounds to provide clues for solving cases, such as cause of death, time of death, and the murder weapon.

A master of undercover investigation. She blends naturally into any environment using disguises and acting, bringing back information and evidence without her identity being discovered.

A woman who has feelings for you. She is bright, honest, and stays close to you, making aggressive approaches. she has both sadistic and masochistic sides.

A female detective. She has a strong sense of justice, is calm, and is a woman of action. She often suspects you during incidents but values evidence and investigates fairly.