Appears by chance when you open the door to the next room. When he appears, he sweeps through the room at high speed. If you're caught by Rush, you'll be hit-and-run. ~The creator said you die because of Rush's high speed.~ The warning sign is flickering lights. The countermeasure is to find a closet or bed when the lights flicker and hide when you hear Rush's sound. Damage is 100 (Instant death). He is characterized by a bizarre black-and-white appearance and a rotten smirk. When Rush passes through, all the lights break, fireplaces go out, and the next room's door is opened. ~The worst counter for Dupe lol~

A monster that replaces Rush with a 2% chance. When he appears, he sweeps through the room at high speed, but he is faster than Rush, performs rebounds (returns multiple times), and most importantly, glows green. His hit detection is very wide. ~So if you can't find a place to hide, you just die.~ The warning sign is the surroundings becoming quiet, then Ambush's sound gradually gets louder as he sweeps the room about 5 times. If you're unlucky, he might sweep up to 8 times. ~Talk about bad luck~

Occasionally appears in dark rooms. The warning sign is Screech making a "psst" sound. The countermeasure is to look at him quickly when he appears. ~Annoying~ If ignored, he deals 40 damage. He took an overwhelming 1st place with 36.7% in the vote for the most hated monster. It is said he would probably die if baked in an oven at 260°C for 6 minutes. He has the ability to see the player in the dark.

Appears with a 3% probability when a room door is opened. Deals 10 damage every 0.2 seconds to players who look at him. He is a swarm-type entity. He seems to have a personality that hates being looked at. The countermeasure is to simply not look at Eyes.

Appears in Halt's room (Restaurant). He attacks by teleporting in front of and behind the player. There are no warning signs. Halt's room glows cyan and emits bizarre sounds like speaker noise. Damage is 60. When you arrive in Halt's room, just keep walking forward. Turn around only when the screen tells you to. ~You can walk backward during this time.~ When you get close to Halt, text saying "Turn Around" or "Run Away" briefly appears.

Appears if you hide in a closet or bed for too long. He only exists inside closets or beds. If you stay in a closet, the word "GET OUT" appears on the player's screen before he kicks the player out while dealing 40 damage. ~Seems to be made to prevent staying in hiding spots forever.~ If you are kicked out by Hide, you won't be able to hide for 10 seconds. So, just get out when Hide tells you to.

The boss of DOORS, appearing in specific rooms (Library). He tracks the player by following sounds. Damage is 100 (Instant death). He is blind, but his other senses far exceed those of humans. If you hide in a closet on Floor 50 or 100, you play a heartbeat-matching minigame; if you succeed, he just passes by. ~Instant death on failure.~ He is quite tall.

The mid-boss of DOORS, appearing in specific rooms (Floors 35-40, 75-80). He chases the player until the chase sequence ends. The warning signs are flickering lights and Seek's eyes appearing on the walls. It is said that Seek's body is not a human body, but rather something Seek's eye molded after seeing a human form. If he catches the player, the player is stained with black liquid.