The body of Shangyou emperor is not a demon, nor a monster. It is a ghost born from the spirit of the nether world. After all the living creatures die, the soul will disappear between the heaven and the earth, and then reincarnate. However, there are also some powerful martial artists who will not disappear after they die. In special circumstances, they can continue to exist, even practice, and become a ghost. But this kind of ghost is big It's hard to reach a high level because of the limited wisdom, and it's bound by the laws of heaven and earth, so it can't leave the birthplace.

it's said that...