What Does It Mean That Everyone Has Ghosts in Their Dreams?

[Main World + Dungeon] [Thriller] [Enjoyment] [Sane] [Props] Xu Ying originally thought that he would wake up normally after surviving the nightmare with the ghosts hidden inside him, but when he opened his eyes, he came to another world where everyone used dreams to "detain" ghosts. "What, you said there are no ghosts in the world?" "Then your dreams at night are all empty?"