A Demon or daemon (from Koine Greek δαιμόνιον meaning "goodlike power, fate, god") is a supernatural, often malevolent, being prevalent in religion, occultism, literature, fiction, mythology and folklore. The original Greek word daimon does not carry the negative connotation initially understood by implementation of the Koine δαιμόνιον (daimonion), and later ascribed to any cognate words sharing the root.
In WGN Salem a demon is a supernatural creature that by means of witchcraft may obtain a physical body. The primary demons that are present on the show are the Familiars, lesser demons in the guise of animals and that act as witches' servants. Even the Devil can be considered in some aspects a demon, although better fits the Deity description.