Before the end of the 19th century, the Greeks believed that the corpses of werewolves, if not destroyed, would return to life in the form of wolves or hyenas which prowled battlefields, drinking the blood of dying soldiers. In the same vein, in some rural areas of Germany, Poland and Northern France, it was once believed that people who died in mortal sin came back to life as blood-drinking wolves.
These "undead" werewolves would return to their human corpse form at daylight. They were dealt with by decapitation with a spade and exorcism by the parish priest. The head would then be thrown into a stream, where the weight of its sins was thought to weigh it down. Sometimes, the same methods used to dispose of ordinary vampires would be used. The vampire was also linked to the werewolf in East European countries, particularly Bulgaria, Serbia and Slovenia. In Serbia, the werewolf and vampire are known collectively as vulkodlak.
In folklore, a revenant is a visible ghost or animated corpse that is believed to have revived from death to haunt the living. The word revenant is derived from the Old French word, revenant, the "returning" (see also the related French verb revenir, meaning "to come back"). Revenants are part of the legend of various cultures, including Old Irish Celtic and Norse mythology, and stories of supposed revenant visitations were documented by English historians in the Middle Ages. The terms "vampire", "ghost", and "revenant" have been used interchangeably by folklorists, while some maintain that vampires derive from Eastern European folkore while revenants derive from Western European folklore, many assert that revenant is a generic term for the undead.
Augustin Calmet conducted extensive research on the topic in his work titled Traité sur les apparitions des esprits et sur les vampires ou les revenans de Hongrie, de Moravie, &c. (1751) in which he relates the rumors of men at the time: Calmet compares the ideas of the Greek and Egyptian ancients and notes an old belief that magic could not only cause death but also evoke the souls of the deceased as well. Calmet ascribed revenants to sorcerers who sucked the blood of victims, and compares instances of revenants mentioned in the twelfth century in England and Denmark as similar to those of Hungary, but "in no history do we read anything so usual or so pronounced, as what is related to us of the vampires of Poland, Hungary, and Moravia."
A possible precursor of the revenant legend appears in Norse mythology, called the draugr or aptrgangr, literally "again-walker", meaning one who walks after death. Stories involving the aptrgangr often involve confrontations with the creature. The aptrgangr resists intruders to its burial mound and is often immune to conventional weapons, which renders the destruction of its body a dangerous affair to be undertaken by individual heroes.
In the folklore and ghost stories of Eastern Scandinavia, Finnish "dead-child beings" are described as revenants animated by restless spirits that could be laid to rest by performing baptism or other religious rites.
References to revenant-like beings in Caribbean lore are often referred to as "The soucouyant" or "soucriant" in Dominica, Trinidadian and Guadeloupean folklore, also known as Ole-Higue or Loup-garou elsewhere in the Caribbean.
