The undead are creatures that are dead but are animated and behave as if are were alive. They are common in fantasy and horror role-playing games, occasionally appearing also in science fiction. Undead may be reanimated by magic or other supernatural forces, either by the application of the deceased's own life force or by that of another being (such as a demon).
The undead may be incorporeal (e.g. ghosts) or corporeal (e.g. mummies, vampires and zombies). They may also retain the memories and personalities they had while alive, suffer a form of amnesia on death, or be largely mindless. Mindless creatures are mostly used as monsters in action-adventure games, being a type of creature that can be attacked and killed without any moral ambiguity. However, undead that retain their minds may be more complicated, and can even be player characters in some games (such as several World of Darkness games published by White Wolf Publishing, or others like Morts for Fate Core).
Undead are generally resistant to most mundane weapons and attacks, but vulnerable to divine magic and sometimes other specialised attacks.