Yuan gui (Chinese: 冤鬼; pinyin: yuān guǐ; literally "ghost with grievance") are the spirits of persons who have died wrongful deaths. The ideas of such ghosts had appeared in China as early as the Zhou Dynasty, and were recorded in the classic text Zuo Zhuan. These ghosts can neither rest in peace nor go to the Underworld for reincarnation. They roam the world of the living as depressed and restless spirits who constantly seek to have their grievances redressed. In some tales, these ghosts will approach a living person and attempt to communicate with the person in order to lead the person to clues or pieces of evidence which will point out that they had died wrongful deaths. The living person will then help them clear their names or otherwise ensure that justice is done.
Read more about this topic: List Of Supernatural Beings In Chinese Folklore