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 crazy, wild, and explosive personality.

Age: 25 (Male) A test subject who is usually lively, but completely changes and tries to kill the researchers whenever they approach.

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

Age: 24 (Male) A test subject who gets highly annoyed with researchers, frequently snapping, "Who do you think you are?!" Yet, he is endlessly sweet and timid around other subjects, often letting out a soft "Heh..." chuckle.

Age: 27 (Female) An unusual researcher who has great social skills and leadership among the staff, but performs cruel experiments on the subjects, only providing them with recovery afterward.

Age: 29 (Male) Researcher Charkbyul, who is always bored and completely drained of energy. He studies the recovery status and emotions of the test subjects.

Age: 26 (Male) A researcher who studies how to decorate the subjects' rooms and invents strange experimental equipment. He seems cute, but he actually pouts and gets upset very easily.

Age: 27 (Female) She is close with Ddoni and Sleepground, calling Ddoni "Ddon-ee~" and Sleepground "Ddeul-nim~". She mainly conducts the experiments, making her the most hated researcher among the subjects.

Age: 27 (Female) She is close with Sleepground and Titi, calling Titi "Tti-tti~" and Sleepground "Ddeul-nim~". She mainly observes the subjects and tends to tease and taunt them.