Dance Partner of the Underworld

There are many strange phenomena in buildings without basements. There will always be sighs or loud footsteps from the ground, a bloody handprint on the door, a dead cat that has been disemboweled, a body that has been dead for six months embedded in the wall, cries for help, and a room with a "legend"... Who lives underground without an entrance or exit? Who is pretending to be mysterious and mysterious? Is it the legendary man in black clothes and a black hat, the gloomy building manager, or... The ghost who was persecuted to death? ? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.