Except the human world. Is there really a demon world, a fairy world, a ghost world and so on?

There is no distinction between the underworld, the celestial world and the ghost world. People make up their own imaginary worlds. Since ancient times, people have thought that there is some kind of god at work for unexplained phenomena in nature, so wizards and divination have appeared. With the development of science, people no longer believe in illusory things.