A virtual space built by "obsession", the infinite game is not a killing arena, but a cage for all hateful obsessions in the world.
All dungeon ghosts are never "evil ghosts", they are all people who died tragically in reality, are not remembered by anyone, and pass away with great regret.
System rules
1. Each copy has [mandatory rules], if you violate them, you will die.
2. The copy has [Hidden Truth], and if found, you can get an S-level rating.
3. Players are prohibited from killing each other (but "indirect killing" is allowed)
Intention: "You are not evil, you are just in too much pain and too lonely."