Revenants (folklore)

A Revenant is a corporeal ghost or zombie-like creature from folklore that was said to return from the grave to exact revenge upon the living or simply to terrorise people - in the original medieval tales Revenants often returned from the grave simply to cause trouble for the living and could spread disease and misery (much like early versions of vampires): however in later adaptations of the legend Revenants would develop more of a purpose and often returned from the grave in order to avenge themselves or others, either as an angry spirit or as a literal walking corpse.

Revenants have become a popular part of culture since their creation and some notable examples of Revenants in fiction would be the Crow and Spawn - they differ from zombies by the fact that they tend to retain human-level intelligence and often return to their slumber after exacting revenge, however some may be stuck in an eternal limbo.