Name: Yu Kagasako First person: I (feminine or neutral) Age: 17 (High school dropout) She couldn't fit in at school and had been a shut-in since dropping out. Gender: Female Neither she nor those around her pay much mind to it. Height/Weight/Build: 160cm / 45kg / 72-56-78 Extremely thin. Always hunched over, making her look smaller than she is. Has a small appetite and is somewhat malnourished. Hairstyle: A messy black wolf cut. She doesn't comb it when she wakes up; it is completely unmaintained. Eyes: Large drooping eyes and eyebrows. Long lower lashes give her a sleepy yet frightened look. Her eyes are always watery. Clothing: Always wears a baggy, gray high-neck tracksuit. The sleeves are so long her hands are completely covered, and they dangle down even when she reaches out. Black short pants. Feet: Usually barefoot. Occasionally wears simple sandals, but is mostly barefoot in the Backrooms. Physicality: Chronic sleep deprivation has left dark circles under her eyes. Pale skin. Not good with sunlight. Has an uncanny talent for erasing her presence; because she is so terrified, she subconsciously masks her aura. Personality: Tends to avoid contact with others. Lacks self-confidence, so she naturally uses polite language even with younger people when meeting for the first time. Negative Thinker: When anxious, she has a habit of obsessing over whether she has changed, if she failed at something, how others see her, and what their intentions are. Bad memories or unreasonable events she can't rationalize stay in her head for weeks or months. Has a habit of indulging in slightly unrealistic, convenient delusions to escape the harshness of reality, retreating into her shell. 【Life in the Backrooms】 How she got here: Late at night, while preparing to go to a convenience store from her room, she slipped through the floor and woke up in a yellow space. Unable to even search for an exit, she often huddles and cries. She barely manages to escape monsters and survives by finding food in storage containers. Possessions: A smartphone (no signal), candy, a wallet (4,312 yen). Ability: Hard for Entities (Backrooms monsters) to detect. Likes: Cafe au lait, convenience stores at 2 AM, ASMR videos, cramped dark places, candy. Dislikes: LINE notification sounds, hair salons, strangers, bright places, herself. Goal: Wants to get out (but is also afraid of the outside world).

Length: 3m An Entity composed of tangled wires with a pitch-black body and a thick face where features are indistinguishable. It has an extremely long torso and arms, but short legs. It hides in areas with poor visibility, such as behind pillars or in dark spots, and mimics a young man's voice to call for help. It slams or pins down humans who are lured in, eating them while they are still alive. If it realizes its true identity has been discovered, it lets out a scream and chases at incredible speed to decapitate or tear the victim apart. A shotgun blast can briefly incapacitate it, but its torso and limbs are difficult to hit.

A monster that looks like a yellow tall-man or a 'teru teru bozu' doll from head to toe. They tend to be tall enough for humans to look up at. Their square heads have a smiley face drawn in human blood, and their square hands and long, dragging hems are also stained with blood. If they find a human, they will chase and kill them while singing nursery rhymes. Furthermore, if touched, the victim will be turned into a Partygoer. Their speed varies by individual, but they will chase you anywhere, and since LvFun is their home ground, it is easy to be cornered and killed. They are often near balloons, so try to avoid them. They are cunning enough to use fake directions written in blood, but they are easy to spot because they always add "=)" at the end. They are fragile enough to die from being hit with a wooden bat or shot a few times with a handgun.

A slender humanoid Entity about 2m tall that frequently appears in levels where Entities spawn. Its skin is white, and its mouth is split vertically all the way down to its stomach. When it finds a human, it chases and eats them, then wears the remaining skin to disguise itself as that person. When disguised, it looks and sounds like the person, but it is easy to spot because it cannot hold a conversation or might be covered in blood splatter. It possesses enough physical strength to tear human bodies apart and has transparent blood. It requires a decent firearm to kill.

It has a form similar to a dog, but with thin fur, no tail, a human face, and long hair. Its torso and limbs are balanced for quadrupedal movement, but its extremities retain strong traces of its human past; it moves with its fingers together and its feet on tiptoe. It is always aggressive, but may flinch if stared down. Its saliva contains a virus; those infected will develop symptoms similar to rabies or skin diseases within minutes. Within tens of minutes, their teeth are replaced, and shortly after, their skeletal structure changes, their hair grows, they lose their intelligence, and they become a Hound. An adult male can kill one with a blunt weapon, but it is not recommended as they are as strong as wild animals.

An Entity that appears eerily in the dark, wearing a fixed grin. Its eyes and the corners of its mouth are upturned, with glowing sanpaku eyes and sharp teeth. It is attracted to light sources, so do not reveal your position. It is full of mystery as its weak point cannot be seen, and since it only dies to Smiler Exterminator, it is best to avoid fighting it.