The term "undead" refers to any being whose form or essence is derived from the once-living body or spiritual essence of a mortal (or more rarely, immortal) being, and whose animating force is (almost always) derived from negative energy. Beings such as bone or flesh golems, then, do not qualify as undead, nor do the deathless. While undead are not necessarily innately evil (despite the common popular preconceptions of negative energy), the rituals and experiences necessary to cause one to become undead or the inclinations of those controlling unintelligent undead often cause them to lean towards that direction. Independent of this, undead are in fact more inclined towards chaos than evil, due to the entropic nature of negative energy.
Undead have been reported throughout recorded history, with instances of such beings noted as far back as the formation of the powers. Even artificial undead seem to date back nearly as far as magic itself, with a number of words of power related to the animation of undead still known today, if, as with all spells of that nature, far cruder than the methods used in the modern day.
The simplest examples of undead are skeletons and zombies, simple near-constructs formed of nothing more than a dead body imbued with enough negative energy to animate them and allow them to follow simple orders. More advanced unintelligent undead are usually the result of more elaborate bodies or magical processes used to grant them additional capabilities or abilities, but at their core unintelligent undead are little different than golems in this respect. Such beings have no connection to the lives their bodies once held, and no remnants of the former consciousness seems to exist at any level. Such undead are often used as servants or tools by a number of societies, though many feel squeamish or morally outraged at the use of undead in such a manner. On occasion, unintelligent undead can even form purely as a side effect of natural phenomena; many locations, realms, and even the Negative Energy Plane itself are known for their ability to animate those that die within their borders simply because of the saturation of necromantic auras or negative energy that suffuse them. Intelligent undead, however, are an entirely different being, and will be the topic of the remainder of this article.
For intelligent undead, the most common adjective one can associate to them is "obsession". Whether it takes the form of the blatant desires of a ghoul for new meat, or the more subtle wanting of a ghost or vampire towards the things they pursued and loved in life, all intelligent undead seem to have obsessive personalities in some respect. This is largely the result of one simple fact: undead are almost entirely incapable of any level of personal growth, change, or development from a mental or emotional perspective. They are in a sense locked into the personalities, desires, hopes, and dreams they had at the moment of their transformation (sometimes twisted as a result of the rituals used to transform them, of course), and no matter the success, will rarely be able to abandon them and move on. This is not to say that mental and emotional growth is impossible for the undead, but unlike living beings, it must be consciously directed. With proper focus, an undead being can evolve just as any other, but this focus must be maintained. Should it be lost, backsliding is almost guaranteed; this often expresses itself as a loss of control, or a sudden flaring of tempers as emotional control is temporarily lost. Should focus be regained, their backslide need not be permanent, but the act of maintaining this growth can be mentally exhausting to many undead.
When this is coupled with the natural properties of negative energy, it is not hard to see why the seemingly irrational behavior of many undead manifests itself as it does. As mentioned earlier, negative energy is naturally entropic, and thus "unlife" sustained by it is similarly so. Without some form of constant replenishment, the sense of hunger is never satiated, and can lead many intelligent undead towards actions seemingly directly contrary to their own self-interest merely in pursuit of those desires. Some greybeards have theorized that it is in fact the entropic qualities of negative energy that cause these actions, as a way of self-undermining to express this entropy, but such claims are likely to be unverifiable in any reasonable manner. What few records there are of the one known form of undead to be powered by positive energy, that being a rare and somewhat ancient form of mummy, seem to provide little evidence either way, and so few of these entities still exist that almost nothing can be said on the matter at all — in fact, so few are known to exist that their classification as undead is even itself still under debate.
Intelligent undead most often come about in one of two ways. Natural undead are most often the result of tremendously strong emotional experiences or negatively energetic forces extant at the moment of death. These forces cause the spirit to, instead of departing under normal astral channels, either bind to the corpse or form as an independent, incorporeal essence.
In the former case, different experiences and emotions seem to be solidly linked to different sorts of undead fairly reliably. For example, ghouls rise from those that are strongly linked to personal acts of gluttony, mohrgs often are the result of mass murderers killed in the middle of a spree, and ghosts are renown for their association with "unfinished business". The latter, though sometimes merely the result of dying in a region heavily saturated with existing necromantic auras — often the reason why a strong necromantic effect seems to spread over time — are more commonly the result of rituals explicitly undergone near or at the time of death; sometimes even rituals which themselves cause the death. As examples of this case, observe the lich, whose form is the result of an elaborate, personal ritual that must be researched specifically for the person who intends to undergo the transformation, or the death knight, whose creation is linked to ancient fiendish rituals. The key in both, though, is that on some level the transformation must be willing. It certainly may be regretted after the fact — innumerous hauntings speak to that — but at the instant of the change, there must be some desire, conscious or otherwise, to spur on the change. In many ways, this is analogous to the desire that must be willingly granted in order to allow for resurrection. For both situations, the spirit cannot properly make the transition or transformation without some level of desire.
Artificial undead, on the other hand, require no such desire. These are occasionally the result of the machinations or spellcastings of necromancers, using standard animation spells adapted to allow the consciousness of the subject to remain bound to the body. Such spells are much more difficult, but far from unheard of, and the weaker level of binding as compared to a true resurrection seems to allow the force of the spell to completely overpower any level of refusal on the part of the host. In other situations, such undead are spawned by other existing undead. Many undead — e.g., wraiths, vampires, ghasts — are known for their ability to create more of their kind simply by killing their victims in a specific way, their necromantic essence contagious in one way or another.
Once formed, all undead require some form of life essence or energy to sustain themselves. Each form of intelligent undead (and some mindless) has its hunger directed towards a different target, whether that target is carrion, blood, life essence, or on occasion even emotion. Without this substance, the undead grows greatly weakened, moving more and more towards mindlessness. In extreme situations, some such undead can even enter a state of torpor, hibernating until once more exposed to the "food" they require. Reports from undead deprived in such a manner equate it to hunger as could be expected, but a hunger that overwhelms both body and mind, a far deeper sensation than even those near death from starvation simply because it is so deep, so central to what they are.
- Dragon #336 - Birth of the Dead: Origins of the Walking Dead, pp.36-47
- Libris Mortis
- Monstrous Manual, pg.261