From the French word revenir meaning 'to come again'. They are the restless ghosts who return eternally to the scenes of deadly crimes, of which they were either victims or perpetrators.
The victims return to bewail their untimely fates: the perpetrators because their bloody deeds deny them eternal rest. Revenants of murderers can be very dangerous to the living and should be dismissed by the rites of exorcism.
In Haiti, the voodoo island of the West Indies, revenants are of a different character. They are the ghosts of dead persons who feel they are fading out of living memory, and return to give vigorous and sometimes unpleasant reminders that they still exist in another dimension.
A revenant may jolt a relation's memory with such actions as overturning a boiling pot into the fire, inflicting skin diseases, or leading a child away to become lost in the jungle.