So base of story goes like this....many years ago bodhisatwa kishitigarba vow that he will gain enlightenment on the road of hell(naraka in sanskrit)....and 100 years ago( time from prospective of MC) he really gain enlightenment in the centre of hell and established his bodhisatwa kingdom. ..but now problem occurs, the aura of his enlightenment was so strong that most of the souls and the operators of hell ( emissaries) just can't stand it. As all of them were just creatures of yin, most of the strong and evil souls just went puff. So as emissaries of hell they also can't stand aura so they one by one went to some other or went puff. The one of the strongest emissary the grandma meng who specialises in removing memories of deceased went to mortal world to find someone who can atleast operate hell in lowest settings lol...and she found mc who had eaten an eternal fungus and can live forever. The one who eat that fungus will live forever as both the hell and mortal world oppose his existence. He can't die in mortal world and if he can't die mortal world is like curse for him so as if he can't die hell also despise him. But grandma meng make him emissary cause aura of bodhisatwa can't affect him as he is mortal and he can almost live forever...and now read more details your self.
