Undead

Undead are the once-living who have been animated by supernatural forces. They are ageless, unbreathing, undrinking, uneating, creatures. They are immune to paralysis, poison, sleep effects, stunning, and mundane disease. The vast majority of undead creatures operate on animal-level intelligence. It isn't until they are directed by more powerful entities, such as demons, necromancers, vampires, or some other creature capable of psychically controlling them, that they act with any measure of intelligence.

Origins of Undeath
There are several different ways of becoming an undead:

Intentional Renimation
A living creature willingly subjected themselves to undeath. The most common reason for doing this is fear of old age, a thirst for power unobtainable in a mortal lifespan, or some other similarly selfish reason.

Minions
Undead minions are called together by necromancers and other grave-traffickers to act as soldiers, servants, and labor for their own means. These mindless creatures are magically crafted by spellcasters in any number of ways.

Atrocity
A living creature willingly committing an atrocity or especially heinous act can transform the creature into a member of the undead. The scope and intensity of the atrocity is somewhat random, though requires especially horrible acts such as genocide.

Unfinished Business
On the rare occasion, living creatures with strong wills and unfinished business may rise from the grave in an attempt to accomplish whatever deed left unfinished. Once the object of their unfinished business was completed, their soul would finally rest and move onward.

Blood Curse
Vampirism is a form of undead, and turns any creature it infects into a member of the undead. Unlike most other undead, vampires do not lose their mortal or humanoid appearance; mostly appearing as they did before they were turned (bloodline specific).

Death by Undead
Almost all members of the undead can inflict undeath upon others through violence. When an undead kills a living creature, the living creature has a large chance of rising as a member of the undead that struck them down.

Skeletal

 * Liches
 * Lich
 * Demilich
 * Skeletons
 * Skeleton
 * Skeletal Steed
 * Skeletal Harpy

Corporeal

 * Deathlock
 * Dracolich
 * Dessicator
 * Dreadknight
 * Entomber
 * Forsaken
 * Ghast
 * Graven One
 * Ghoul
 * Mummies
 * Mummy
 * Mummy lord
 * Necromental
 * Nightshade
 * Nighthaunt
 * Nightwalker
 * Skin kite
 * Vampires
 * Vampire
 * Vampire spawn
 * Vampire Master
 * Vampire Ancient
 * Vampire Lord
 * Wight
 * Zombies
 * Zombie
 * Ogre zombie
 * Observer zombie
 * Minotaur zombie

Incorporeal

 * Dream vestige
 * Ghost
 * Quell
 * Shadows
 * Shadow
 * Shadow assassin
 * Specters
 * Specter
 * Poltergeist
 * Wraith