I don't remember the chapter but we see it when Nok was remembering his childhood with his mother alive.
He was playing and got sick with a flu and fever, he wasn't meant to die but some new messengers from the underworld took him by mistake and just before they made him to cross the river they realize their mistake.
Jaeshin was passing by. Nok woke up able to see ghosts. Also it seems little Nok remembes Jaeshin and his kindness, projecting him in his friendship with that traitor. Of course he forgot him when he grew up
Yeah. But I mean how can you mistakenly bring people to the underworld like it's an everyday problem if we want to be serious here, the messengers are the main cause of the issue (assuming that they suck at doing their job)
Jaeshin wouldn't have known and want to cause Nok his condition. It's truly an unfortunate that their fate entertwined like this and it wasn't even his fault. Jaeshin truly have come a long way in understanding what love is. Need to understand first why Nok crossover that river if he isn't dead yet. If I understand correctly it is like Nok is constantly between life and death. Like is he meant to die earlier or was forcefully sent to underworld without dying