Causes
Causes of undeath
- Voluntary transformation — This is where a living creature willingly undergoes a process of self-transformation to undeath. One common motive is the desire for immortality.
- Spellcasting — Clerics and magic users can create undead undead creatures to serve them. For example (and my favorite monster from the AD&D Monster Manual, is the quasit.
- Atrocity
This is where a creature is transformed into an undead creature due to committing some especially heinous act.
- Unfinished Business
This is where a creature becomes undead after death due to some important deed being left undone.
- Death by wounds caused by another undead
Most forms of undead will cause their victim to become one of their type by causing a mortal wound. This is common in ghouls and vampires.