Revenant

Revenants are playable undead creatures in 4th edition Dungeons and Dragons meant to serve a purpose dictated by either the Raven Queen or some other divine/magical individual who gave them life in a body based on the corporeal form their soul once inhabited. They are not necessarily bound by the will of the person or deity who resurrected them, though; they have free will and are completely autonomous. A revenant's body's features are mostly similar to the previous life's, but the skin and hair color are ashy shades of gray or white or black and instead of finger/toenails they sometimes gain claws like talons. They don't always have a vulnerability to religion-based or radiant powers and are not inherently evil-aligned undead entities. They're weird and can be interesting characters depending on who's playing them and what the player's concept for the character is.

Revenants in earlier editions were an uncommon undead monster, based upon certain real-world mythologies. They were restless souls whose obsession with something or someone (stereotypically, murdering the bastard(s) who murdered them) was so strong they rose up from their grave, and in some versions could not be killed permanently; they would just come back again and again until their driving obsession was nullified.