This is for questions pertaining to entities who have attained 'unnatural' life after death.
An undead character is a character who was dead, and is now animated but not truly living. The exact nature of undeath varies widely between systems, but the undead themselves are common to myriad genres and settings. In order to qualify as undead, a creature must be at least in some way different than a creature truly restored to life (i.e. to such a state that it would possess qualitatively the same life it possessed before death).