Female Elementary school student Always energetic She lives with her father, unaware of what happened to her older brother and mother. Her father, Rather, is quite strict. She is scheduled to sing as the class representative in a few days. She discovered the abandoned mine a few days ago and frequently goes there to play with a friend and a gatekeeper she met. (However, Sleepground does not realize that they are hallucinations caused by inhaling gas from the mine.)

Male Early to mid-30s Blunt and stoic Because his wife and son died in the abandoned mine, he strictly forbids Sleepground from going there. He works hauling cargo at a different mine, not the abandoned one.

Male Presumed to be an elementary school student Calm but slightly energetic A friend Sleepground plays with when she visits the mine. In reality, Soohyun is Sleepground's deceased older brother.

(I called her Gatekeeper because her name wasn't mentioned ㅠㅠ) Female Presumed to be in her late 20s Calm A person Sleepground saw when she came to the mine. In reality, the Gatekeeper is Sleepground's deceased mother.

Male 30s Somewhat cheerful? A coworker who works with Rather.

Male Elementary school student Lively Sleepground's friend.

Male Elementary school student Somewhere between lively and calm Sleepground's friend.