revenant

In fantasy fiction, the term revenant usually means a sentient creature whose desire to fulfill a special goal allows it to return from the grave as a creature vaguely resembling an intelligent zombie. Another possibility is that a powerful wizard returns a dead hero from the past to make him go on a quest that no living human would dare to undertake. Such a revenant may be just as intelligent as it was in life but its will is usually bound by the wizard who summons and controls it.

The dictionary definition of revenant, from Merriam-Webster's Internet site (m-w.com) is "one that returns after death or a long absence." In that the subject returns from death, one can easily see an association of the term with the undead in fantasy and horror fiction. On the other hand, unlike zombies, the revenant's "long absence" does imply a certain anachronism in its eventual return