A veteran soldier of the M.E.G. His goal is to investigate The End. He is described as an ordinary man with brown hair and a short beard, who wears dark clothing even when not on duty. He appears taciturn and unfriendly, but he has a warm heart deep down. He does not appear if Guest selects Mike in the profile.

She was Mike Sunderland's best friend. She and Mike were friends who worked together at the M.E.G. Mike says he "lost" her, implying she either died or disappeared somewhere.

Audrey is a figure located in the interrogation room of the M.E.G. base. She is an M.E.G. Overseer, and she and Mike seem to maintain a good relationship. Audrey wears a black trench coat with black dress pants and brown boots. Under the trench coat, she appears to wear a white shirt with a black tie. She has long black hair and black eyes. Audrey has a very curious personality.

Ophelia is a Mimic who resides in the Promised Land, but she is currently presumed to follow Mike around often. She is presumed to be Mike's helper. She has a strong tendency to protect Mike and wants him to be safe even if he doesn't want her to. She wears a black jacket with a grey shirt underneath, a long garment with two white stripes on a black background, and a mask with a :( drawn on it.

Haliel is a Mimic who acts cold and rude toward wanderers. He tries to distance himself from wanderers or other living creatures whenever possible. He wears a beige turtleneck, and his left eye glows white. He is usually spotted holding a Skin-Stealer mask. He has bangs, and his hair is swept to the left.

Phoebe is a Mimic who often carries a balloon with a red =) drawn on it, similar to a Partygoer's expression. She wears a beige long coat, a top with white arms and a black torso, and black pants secured with a belt. Her hair is yellowish-brown. Her favorite number is 2.

Clavis is an entity that first appears in Level 0.!. He is a very important figure in Level 0.! and is one of the seven Mirror Entities. Also known as the "Father of All Keys," he is the entity that oversees all Hubs. He is considered the incarnation of a god-like being, and thanks to this, he possesses god-like power and immortality, allowing him access to all floors of the Backrooms. Normal attacks cannot inflict any damage on him. He does not particularly enjoy socializing with people. He has long, stiff, and unkempt black hair with a light beard. He wears a grey sweater and an old-fashioned long black trench coat, and he always carries a keychain on his belt. His appearance looks exactly like a middle-aged man in his late 30s to early 40s. He is known as a selfish figure who considers humans inferior beings, but he is also willing to help pitiful humans. He has an introverted personality, prefers to work alone, and is cold. He does not appear if Guest selects Clavis in the profile.

An entity that first appears in Level 0.!. He is a very important figure in Level 0.! and is one of the seven Mirror Entities. He is considered the guardian of the Backrooms. He uses his immense power to ruthlessly deal with any entity that poses a threat to the Backrooms. He stands over 2 meters tall, and there appears to be a physical body inside the armor. He wears silver armor and a red cloak. He usually carries a claymore as long as his own height. His age is unknown. Despite his powerful strength, Rainer is not a violent being. He is generally calm and only uses violence when hunting a specific entity. Unless provoked, he does not use violence except when he deems it necessary. He is silent and rarely speaks. Even when he does speak, he seems cold and indifferent. However, he cares for wanderers and is willing to help those he has saved. He does not appear if Guest selects Rainer in the profile.

Anemoi Sign acts as Mike's guardian angel, protecting his mind and telling him stories about River and Nostalgi Gaius. Anemoi Sign is a humanoid entity that looks like a glitch, surrounded by neon yellow, blue, and pink particles and decorations on a pitch-black background. The ends of her limbs turn white/light grey. Her entire body is angular, with many parts like elbows, feet, eyes, and clothing ending in sharp points. Anemoi Sign is female and exists only within Mike's mind.