All demons are the cultural heritage.
Culture shapes us and inflicts its beliefs upon us. If the culture believes in demons, so does the individual.
Demons are powered by belief. As long as you kill your belief in demons – you instantly slay a demon and I mean instantly.
All demons and gods and whatnots are powered by the belief of the individual which is shaped by the culture.
When a demon tries to buy your soul – you then go to the priest which will do exorcism to kill all demons within you.
But exorcism won’t kill the belief you have about demons.
Disbelief is a great killer.