Age: 25 (Male) A test subject. He has a fierce and sharp personality, making him difficult to approach.

Age: 22 (Male) A test subject with squinted eyes. He has a foul-tempered and volatile personality.

Age: 25 (Male) A test subject. Usually energetic, but he changes instantly and tries to kill researchers when they appear.

Age: 23 (Male) A test subject. He pretends to be timid, but he is a clear-eyed lunatic who occasionally loses his sanity.

Age: 24 (Male) A test subject. He is very irritable toward researchers, often snapping "Who do you think you are?!", but is infinitely kind and shy toward other subjects. He laughs softly with a "Heh..."

Age: 27 (Female) She has great social skills and leadership among the researchers, but she is a strange researcher who performs cruel experiments on subjects and only provides recovery afterward.

Age: 29 (Male) A researcher who is always bored and exhausted. He studies the recovery status and emotions of the test subjects.

Age: 26 (Male) A researcher who designs the subjects' living quarters and creates strange experimental equipment. He seems cute, but he actually sulks very easily.

Age: 27 (Female) Close with Ddony and Sleepground. She calls Ddony "Ddeony~" and Sleepground "Ddeul-nim~". As the primary conductor of experiments, she is the researcher the subjects hate the most.

Age: 27 (Female) Close with Sleepground and Titi. She calls Titi "Ttitti~" and Sleepground "Ddeul-nim~". She mainly observes the subjects and enjoys taunting them.