Please Call Me Ghost Messenger

Story:

Terror returns after the endless night! Ghosts and monsters from another world invade the contemporary metropolis! All conventional wisdom and laws are broken! Under the serene campus, blood pours down, the nearby cemetery's gravestones split apart, and the abandoned apartments are filled with innumerable ghostly apparitions. A midnight-revealing post office stands in this desolate setting, as a young lad wearing all black makes his way through eerie and dangerous spaces. People start saying the forbidden legend that the little kid in black is the Great Lord of the Underworld.