There are always some people who are selfish and ungrateful. No matter how much others pay for them, they take it for granted.
However, when they died and were reincarnated, they realized that their sins were too serious. Unable to cross the Naihe Bridge in the underworld, one can only fall into the Nine Netherworld's rolling river of blood and float up and down, suffering the soul-eating pain of the blood every day. The resentment in the river skyrocketed.
In order to maintain the stability of the underworld, the king of hell had to make deals with ghosts who could not be reincarnated. The ghosts give part of their souls and then the King of Hell finds someone to atone for their sins. As long as the people they hurt are happy, the ghosts can be reincarnated. But without some soul energy, even if you are reincarnated, you will not have a good life.
Intention: Do not refrain from doing good deeds because they are small, and do not do them just because they are small.