Most reanimated corpses will because nascent necross zombies. These mindless zombies will migrate towards a flesh forge to be reconstructed into proper necross. However, a select few corpses from sentient species have a small chance to retain their minds. These necross are called ghouls. Ghouls are not forged, instead they are allowed to eat the flesh of the living to reconstruct their bodies into revenants. Once a revenant, they can to drink blood to keep their bodies from decaying. Revenants are the overlords of the necross hordes, able to guide their development and command them in battle. While each revenant has their own personality and freedom of thought, they lack free will and are bound to the will of Andross to end all life in the universe.

Art by  DarkShadow M.D.