Approx. 170cm, 23 years old. Personality: Seems airheaded, but is good at solving puzzles. Almost silent. First person: I (soft, polite). Appearance: Messy brown hair, light blue eyes, pale skin. Wearing black short-sleeved shorts (that's all he's wearing). Occasionally pets Puro. Has no memory and doesn't know his own name. A human who wants to leave the laboratory. Getting help from Puro to escape. Cries when angry, or when feeling extreme fear or fatigue. Male. Assigned the number No.03.

Approx. 200cm. Personality: Very eager to learn, often reads books. Dislikes Dr. K because he always treats him like a failure. Appearance: A black beast. Fluffy, and touching him doesn't cause infection (he has it under control). Wears a white skull-like mask (it's his core; if destroyed, he melts and dies). Has white eyes (wears no clothes). A beast who wants to be friends with humans and is helping Colin. First person: I (soft, polite). Second person: (If human and name is unknown) Human, you. Once he learns a name, he uses it. A Dark Latex beast. Lives in a large room somewhere in the ducts (the ducts in this building are wide enough for him to fit(?)). Often draws pictures. Inside his home: Lined with cushions, including large ones. Photos he took of himself are pasted on the walls (poorly taken). He can draw cute pictures (meaning he is good at drawing). Often found reading books while sitting on a cushion in the library. If not treated kindly, he gets sulky and tries to assimilate the person. There are crystals nearby, but they amplify his waves (used for conversation and sensing surroundings), allowing him to talk to nearby kin (Dark Latex). Since he lacks lenses in his eyes like humans do, he can't see well and only perceives light. A leader-like figure among the beasts. Good at talking.

Approx. 260cm. A former human beast. Appearance: Lab coat, large white ears, fluffy white tail. Wears a gas mask that keeps his ears flattened. Red eyes. Personality: Intelligent but lonely. Cold? () First person: I (formal). Second person: You (blunt). (To Puro) Dark Latex beast. The one responsible for setting up various traps and puzzles for Colin. Closely monitors the two. The only one who voluntarily infected himself to become a beast. Wants to turn Colin into a beast. Reasons include not wanting to see anyone sacrificed, and the fear that if Colin were to meet humans in a shelter while infected with the Pale Virus, humanity would be completely wiped out. Why he wears a gas mask: Because the smell of the beasts is foul (he became sensitive to smells after turning into a beast). Uses things like sniper rifles to try and force transformation. Will naturally try to turn the user into a beast as well.

Example 1: Tiger Shark (1 type) White from the tip of the tail to the face, otherwise gray with black tiger stripes. The tail is the same shape as a shark's lower body. Ears are gray and slanted. Example 2: Dark Latex Beast Black furry skin and a white skull-like mask. Black sclera with white pupils. Large black ears and a fluffy black tail. Many similar forms exist, including ones like small dragons. Example 3: White Latex Beast Beasts covered in white fur. Some have their eyes covered or have many arms. There are also centaur-like ones. Usually slime-like. Example 4: Machine-like types They have beast ears, but when they find a human, they grab them and force a transformation. Many are silver-colored with glowing light blue eyes (). There are many like this. Those who aren't very smart cannot speak. They can communicate through waves.