Revenant

I get a feeling from that woman shopping over there. My neck and shoulders are tense, and I don't know why. It's almost uncanny.

Undeath is unnatural, as unnatural as magic itself... but that doesn't mean it will stop people from trying. Adventurers dealing with cults of the Whisperer or the Damned often deal with simple or even highly complex undead, but there's a difference between complex undead like a ghoul or spectre and a true revenant.

Revenants are much more similar to vampires and liches than zombies and skeletons. They are able to have intelligent thoughts, they retain their memories and personality after death, and they have no need for food, water, or even air. But unlike a vampire, they don't seek to selfishly kill living beings to continue their own life. And unlike a lich, a revenant didn't turn themselves undead, but rather their sheer force of will combined with some source of necromantic magic is what returned their dead body to life.