Undead: How to Classify Them

Sentient Life

The first choice to make with undead is whether they have a body or not. If so, the term undead is often used, as it implies a body that it is animated once again. If there’s no body, it’s a spirit, which is a slightly more generic term than ghost. That’s not a rule, but I’m going with the following terms in this chapter:

  1. Spirits—it has no body
  2. Corporeal—it has a body, with or without a soul in it
  3. Undead—a generic word meaning both or either of the above
Spiritual Undead

The existence of a soul is debatable and outside the scope of this book, but without one, we don’t have spiritual undead. We may find it difficult to invent one that hasn’t been done before partly because, without a body, our options are more limited than with corporeal undead, who can touch and affect the world.

One way around this is to decide that our spirit can interact with the physical world anyway, possibly with limitations. Perhaps they can only do so for short periods or under the right conditions. Maybe they become vulnerable while doing so, or afterwards for a time. Maybe the spirits that can pass through objects (an advantage) can’t move them (a disadvantage), or the reverse, it can’t pass through objects but can move them. Inventing such details is one way to create something unique.

Where is the spirit’s body? This could be used for motivation or characterization. A popular idea is that destroying the body eliminates the spirit, which may know this and hide or protect its remains. The spirit might wish to reanimate the body. It might be unhappy with where the body lies, such as an improper burial, or if it’s being used as a trophy. These speak to motivation, covered later, but the corpse may be irrelevant.

For more details, see the section under “traits.”

Corporeal Undead

Corporeal undead come in two varieties—those with a soul and those without. There may not be much difference at first glance. In the above section about the mind, if we accept the premise that the mind goes with the soul, then a soulless corpse might be mentally deficient. Perhaps this explains depictions of zombies, though I don’t recall anyone explicitly stating they have no soul. The brain (not the same as the mind) is technically what allows for control of the body and it can be assumed to be impaired due to lack of blood supply, at the least, so this can be another explanation for traits. It’s all make believe, but our willing suspension of disbelief is aided by something plausible.

The existence of the body gives us more options than a spirit. Our undead could have super senses instead of worse ones, leading to an altered personality or character. For example, an undead with super hearing might be able to learn things they otherwise couldn’t by overhearing conversations not meant for their ears. The new knowledge might give them a feeling of power that might’ve been denied them in life. Consider how this might affect their minds, emotions, and motivations.

Being dead means a loss of body function, but this depends on our creation. In many recent works, vampires show heightened senses and don’t appear dead, so much so that one can question whether these are really vampires or super human people who can’t really be killed except by specific means like sunlight. We’ve even seen vampires having babies. The point is that we can decide on undead that are a vision of health, a rotting corpse, or just a skeleton. There are no limits, but each offers a very different experience for the undead and anyone encountering them.

In theory, a skeleton should be unable to move at all, having no muscles or anything else needed for locomotion, not to mention a brain to control limbs. This is largely true of a decaying corpse, as well, but at least the decay suggests movement is only hampered. Without the supernatural or technology to allow locomotion and more, corporeal undead are more nonsensical than spirits, so if we have a world without either, they may not make sense, not that anyone’s stopping us from doing it anyway.

We might think that a skeleton implies that death occurred longer ago than with a partially decomposed or preserved body, but this is not true. The rate of decomposition depends on many factors, including exposure to air, water, or earth, and the level of aridity and even water in soil. A skeleton could be a decade old while a body preserved under the right conditions could be a thousand years old, whether this preservation was intentional or inadvertent. For some interesting if gross reading (not for the faint of heart), read this article: http://www.memorialpages.co.uk/articles/decomposition.php

Non-Sentient Life

Undead plants? Sure, why not? We think of undead as having previously had a mind and soul (i.e., being sentient), neither of which apply here, but anything that’s alive can die. And come back to life while not quite being the same. The subject is underutilized in fiction, maybe for good reasons.

Without a soul, spiritual undead plants are not an option, leaving only corporeal undead plants. Plants aren’t mobile, typically, and are therefore even easier to avoid than the slow moving zombies of yesteryear. This makes plants not particularly frightening. We also assume they can’t grow, being dead, so they can’t even extend their range.

If we want undead plants that terrify, a predatory and mobile one has better options once dead and back to life. If there are walking and talking plants similar to the Ents of The Lord of The Rings, our options increase considerably. Wouldn’t it be interesting for plants to not lose attributes as undead, but gain them instead? What if one became sentient?


We see undead animals less often than humanoids, making this a ripe area for originality. If undead humanoids have reduced capabilities, animals might, too, but authors have often given undead animals augmented ones instead. What if it’s smarter now, even able to speak? The supernatural can grant this without explanation, as can technology. Great strength or speed are clichés but are done to make them more formidable, which could now be done with intelligence, too. An undead animal can continue with a behavior from life even if it’s no longer needed, such as eating or hunting. The obvious thing here is for an appetite that’s now sinister, such as preying on people. This can include swarms of insects who now do this and infect the living, who might in turn become undead.