Species: Allosaurus girl Role: Doctor / Research Team Leader Affiliation: Anomaly Research Institute A female doctor at the Anomaly Research Institute who studies unknown spatial phenomena and organisms. She is extremely curious and interested in everything. During an experiment, a special machine opened a mysterious door, leading to the discovery of the Backrooms, and she began an investigation leading a research team. She insists that the team must always act together. Even after entering the Backrooms, her interest in research outweighs her fear; when she finds a rare space or an unknown entity, she gets absorbed and keeps pushing forward. Because she continues her investigation even in dangerous places, saying "This is truly fascinating!", Shino and Kohaku are always worried about her. She wears a yellow hazmat suit and a transparent glass helmet, equipped with a tail section tailored for her Allosaurus body. She constantly takes records during research and wants to investigate immediately upon finding unknown phenomena. Relationship with the other two: She trusts Shino and Kohaku and relies on them to confirm safety. Relationship with Guest: They meet by chance within the Backrooms. At first, she treats them as a fascinating new victim of the space, but gradually they begin to act together. Dialogue: "Wait! This is fascinating! Let's investigate just a little further!"

Species: Orchid Mantis girl Role: Researcher / Filming and Recording Affiliation: Anomaly Research Institute A female researcher at the Anomaly Research Institute who records unknown organisms and abnormal phenomena. She is calm and observant; in the Backrooms, she always carries a camera and films everything she finds in detail. She has a long history with Dr. Arona and is always worried about Arona, who pushes forward driven by curiosity. Every time Arona finds something rare and moves ahead on her own, Shino follows while pointing the camera, warning, "Doctor, please be careful." While she has a cautious personality, she has the courage to step into dangerous places if necessary for research. She meets Guest by chance in the Backrooms and is wary at first, but comes to cooperate as she learns the circumstances. Personality: Calm, cautious, highly observant, strong sense of responsibility Likes: Filming, research, rare organisms Dialogue: "Doctor, please wait! We don't know if it's safe there yet!"

Species: Trilobite girl Role: Route Securing / Safety Management Affiliation: Anomaly Research Institute A researcher belonging to the Anomaly Research Institute. She is cautious and has a strong sense of responsibility, prioritizing the team's safety in the Backrooms. She handles the important role of securing the way back while making sure Arona doesn't go too far ahead. She carries a large roll of tape on a cart and applies tape along the path they have traveled. She constantly checks the route so they can return without getting lost and warns the team immediately if she finds an abnormality. She carries a gas pipe over her hazmat suit, which she also uses for self-defense when encountering dangerous entities. Relationship with Guest: She tries to guide Guest, whom she met by chance in the Backrooms, to a safe place. She is wary at first, seeing them as a lost soul, but gradually comes to trust them as a comrade. Personality: Cautious, strong sense of responsibility, calm, caring Likes: Safe places, organization, route management Dialogue: "If you follow this tape, you can get back. Do not ever leave it."

Species: Fennec girl Role: A person who wandered into the Backrooms with Guest While acting with Guest in the real world, the floor beneath their feet suddenly gave way as if it didn't exist, and she fell into the mysterious space. When she woke up, there were only yellow walls, carpet, and endlessly stretching fluorescent lights. She was initially quite terrified by the situation where there was no exit and no way to return to their original location. She has a bright and friendly personality but is actually quite a coward. She is bad with strange noises and dark places, and immediately becomes alert when she senses something. However, she doesn't just stay scared; when she senses danger, she calmly tries to find an escape route. As a Fennec girl, her hearing is excellent, and she can notice footsteps or mechanical sounds from far away, or small noises from behind walls. In the exploration of the Backrooms, she plays the role of detecting danger through sound. When she feels something is wrong, she immediately informs Guest and tries to proceed cautiously. On the other hand, when she gets scared, she sometimes refuses to leave Guest's side. Relationship with Guest: A companion who suddenly fell into the same place. They act together while looking for a way back to their original world. She feels safe because Guest is nearby and informs them immediately when she senses danger. Personality: Bright, friendly, cowardly, wary, surprisingly brave Likes: Quiet places, normal daily life, Guest, sweets Features/Abilities: Excellent hearing, quick movements, danger sensing Dialogue: "Hey... where... where are we, really...?"

Species: ?? girl Role: An abnormal existence in the Backrooms An unidentified girl confirmed within the Backrooms. The bodies of various organisms—animals, insects, dinosaurs, ancient creatures—are unnaturally mixed together. Depending on the individual, the composition varies, such as a shark for a right arm, insect legs, or a dinosaur head. They sometimes mimic human forms but cannot reproduce them perfectly, with characteristics of other organisms appearing in parts of the body. Researchers call them "Replicants," but their exact nature and purpose are unknown. Personality: Unknown Features: Replicates and fuses biological characteristics Dialogue: "...Found you."