Ghost: the natural phenomenon of information extinction.
Before the Ming Dynasty in China, ghosts were not considered to harm people, suck human blood essence and eat internal organs. Because China has great respect and worship for his ancestors. In ancient China, the treatment of good and evil depends on his behavior, not that evil is evil, but that immortality is good. It's like having demons and evil monks. Unlike western angels, they are just and vampires are evil.
Ghosts, also known as undead, are legendary souls left behind after death and are usually considered as ghosts of the dead. Ghosts may not exist, after all, no one can prove it, but no one can explain that ghosts don't exist.