
Uhhhh, because it's against "fate"? They're only job is to help people get reincarnated by passing on that river (forgot the name), not meddle with their business or whatever an evil spirit is doing to the humans. Wasn't it mentioned multiple times that they are not to tamper with a human's fate? Yes, it's cruel, but such is fate. And it's inevitable, sadly.

Yeh I realise they can't meddle with humans and their fate but considering ghosts and that are seen as part of their world and something as part of their job ig I assumed evil spirits would also be considered as something they would have to take care of and not like natural to the fate of humans that they can't intervene in, esp since its not natural to their world/something everyone can see, so with that logic in this case where it has almost completely taken over the human and interfering with the lives of others it shd be justified but ig that's not how it's being interpreted anyway

Nah, I doubt that an evil spirit is something they have to take care of in this context. They’re in hell because they’re not such creatures with compassion. And no doubt, Lee Nok’s name already appeared in the Book of Names, so it is his fate to be [maybe] killed by that evil spirit, using the queen as the host. And what Jae-shin is doing is interfering with that. I get where your frustration is from though. And that makes this story worthwhile, since it gives us these conflicting thoughts and feelings.
I still don't get why the kings of hell would care if he's also vanquishing an evil spirit clearly causing a lot of havoc in the human world, i get shes also part human but like do they not have critical thinking ??? If this isn't part of their job what even is it other than safe passage to reincarnation