Traditionally the Hmong have been animists or spirit worshippers.  Examples include ancestral spirits, house spirits, nature spirits, and spirits of evil.  Ancestral spirits include any deceased member of the family.  The father's side of the family is believed to have the most powerful spirits.  These spirits are seen as returning to and inhabiting the household altar.  House spirits are thought to inhabit the bedroom, household stove, the central post, doors,  as well as each corner of a Hmong house.  Nature spirits include spirits of mountains, valleys, forests, fields, streams, caves, ponds, and winds. The Hmong believe that spirits can affect every detail of life.  Spirits are believed to be good or bad, evil or merely mischievous.  They can help or harm people, animals or crops.  They can bring on disease or injury, physical or spiritual. Spirits can also possess people, requiring a ceremony to exorcise them.