(This update is specially added for Brother 'Huo is Quite Good'[13/20])
A resentful spirit is, in the traditional sense, a "ghost".
They are tormented by the despair and pain they experienced at the moment of death, unable to rest, yet they yearn for rest.
This conflict in their state of existence makes these resentful spirits hostile to all living beings since their birth, wickedly yearning for new souls to join them in experiencing their pain.
Resentful spirits are tough to deal with.
They don't have physical bodies and are difficult to harm with bullets or swords unless you use spiritual energy or fire. For the more advanced spirits who retain all their wisdom and still hate the living, even fire can be ineffective.
Another threat of resentful spirits is, they never appear on their own.
