In my fantasy world, necromancy exists and it is considered "evil". I try to base my world on science, so how would realistic necromancy work? Dead bodies decompose fast, and souls don't exist in my world. Considering that the revived need to remember at least the most important parts of their previous lives, and need to not decompose for a long time (or smell bad), would it be possible? Magic exists, but how would it happen? The revived need to eat and their biology works a lot like it did before dying.

For the best answer, I'll choose something that explains:

  • How would dead bodies be revived?

  • What would be the "expiration" date for reviving someone?

  • What would be the "expiration date" for something revived?

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    $\begingroup$ "How would dead bodies be revived? Magic exists." Well it seems that dead bodies would be revived... By magic. $\endgroup$ – The Square-Cube Law Apr 27 '19 at 14:23
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    $\begingroup$ Important detail: how are your zombies powered? Do they need to eat, drink? Or are their muscle and nerve cells now driven my a magical powersource instead? $\endgroup$ – Starfish Prime Apr 27 '19 at 14:24
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    $\begingroup$ Why shouldn't they decompose, or smell? Why do the revived need to remember parts of their past life? $\endgroup$ – Joachim Apr 27 '19 at 16:37
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    $\begingroup$ This is too story based : you're effectively asking people to invent your system of magic for you. On teh other hand it's perfectly reasonable to answer your bullet points with (1) make up spell, (2) throw dice - use that number and (3) throw dice again and add that to the number from (2). $\endgroup$ – StephenG Apr 27 '19 at 22:56
  • $\begingroup$ Too broad, POB, too story-based, any of these could be used to close this question. Our help center explains that questions must be specific and answerable, must include context, must include restrictions/requirements, and should include research. Basically all of this is missing. We'll help you develop your magic system by answering specific questions about that existing system, but it's off-topic to develop it for you. (Also, SE's model is one-specific-question/one-best-answer. I count 3 questions.) $\endgroup$ – JBH Apr 28 '19 at 5:54

Death is the effect of a vital part of your body failing. It can be a large part, like the heart, or many small parts like the cells of your brain.

Realistic, hard science necromancy would "repair" that damage. That is, you would rebuild damaged cells, using non-decomposed cells (and their DNA) as blueprints. In most parts of the body, exactly replicating the state before death would not be neccessary. You'd simply grow new skin and bones (if your patient had lost an arm), and the result would be a youthful body part without the traces of life such as scars and wrinkles.

But in the brain, you could only repair what was still there, not what was lost. If your patient's brain was complete and undecomposed, that person's memory and personality would still be there after reviving, as both are stored in the form of neuron cells and their connections. But if those neurons or their connections are partly gone, either because the brain was damaged (e.g. in an accident) or has begun to decompose, that part of the person or their memories or abilities would be gone.

Therefore, the longer a person would have been dead, the more of the original person would have been lost and remain lost forever. You could then either revive someone to a state of mental retardation, leaving the lost functioning unrestored, or artificially introduce abilities (such as speech) and knowledge (such as what money is). Artificially introducing abilities and knowledge would result in a functioning human organism with amnesia, that is with only partial or no personal memories. The extent of the amnesia would depend on the extent of the brain damage.

If such a repair were possible, we could not only restore the (recently) dead, but would also have immortality, as the technique could also be applied before death to prevent it.


The limitation on there being no souls puts a stopper on the most of the typical necromancy stories. Most of them rely on there either being a very specific soul that retains the connection after death, or the affinity of a human-shaped body to a human-like spirit.

If your necromancy is something from a Frankenstein story and you need it to sound scientifically plausible, then, as I've read, brain cells retain the ability to react to stimuli 8 hours after death. So, if a necromancer raises the body in this time window, or has a magical ability to preserve the brain longer then that, he can raise the body. If reanimation restarts the electrical activity in the body, then effectively you have a creature with massive whole-body gangrene. I can't say, how long will the resulting zombie be functional, but not for long, unless necromancer has some additional tricks to help (and if he can stop or reverse gangrene, why is he an evil necromancer and not a healer?).

If there are no human souls, but there are some kinds of ethereal creatures, spirits it daemons, they may be coaxed and bound into the human-shaped body - then you effectively may have no limit on reanimation time - a skeleton would serve as well, although it will not have the memories of the original inhabitant of a body (to access the memories you still would need 8-hour limit). In the second case a golem could serve about just as well as a real corpse, though.


To answer your question, i will tell you about my own science-based magic system and how necromancy works in that.

My system treats magical energy as another type of energy, such as thermal or kinetic energy. In order to cast a spell, you convert magical energy into another type (or several types) of energy.

Kinetic Energy

For necromancy, you would convert magical energy into kinetic energy, thusly moving the corpse. In this way, you are not really reviving the corpse in the sense of bringing it back to life, instead you are manipulating it, similar to a puppet master pulling its strings. It is far more accurate to call this reanimation rather than resurrection.

In order to prevent the corpse from decomposing, i use what i call “kinetic barriers”. These are areas of kinetic energy which act like a solid object. Essentially, any force put upon this barrier is resisted as the kinetic barrier pushes against the force put upon it, thusly cancelling it out. In terms of a corpse, the kinetic barrier covers its body and pushes away oxygen and pathogens, preventing the corpse from decomposing. This means that, as long as the spell lasts, the corpse will not decompose and will be able to move.

Electrical Energy

Due to how necromancy works in my world, it means you can’t bring someone back from the dead (unless using the chemical energy method described below). You could control their body but not bring them back to life.

Instead, to somewhat overcome this, i though of using electrical energy much like how a defibrillator is used. In this way, you could ‘revive’ someone by stopping their heart with electricity, allowing it to restart. Whilst this wouldnt work in all cases, it would in the case of a heart attack which could cause someone to ‘die’ (in reality, we know they’re not dead, just suffering from a heart attack. However, medieval people might not realise this and assume the person was brought back to life).

This method allows the revived person to remember most, if not all, of what they did before they ‘died’, prevents them from decomposing and makes sure their biology is exactly the same. However, it isn’t true necromancy, though people may see it as such.

Chemical Energy

This method is a lot harder to perform (and harder to describe accurately). Essentially, healing magic in my world works by converting magical energy into chemical energy and using that to accelerate the body’s natural healing processes.

Applying this to necromancy, you may be able to repair the damaged cells in the deceased’s body using chemical energy. This would cause any internal injuries to be healed and the body to be refilled with blood. In this case, it is perfectly reasonable to call this method resurrection as you are actually bringing someone who died back to life.

There are several issues with this method, though this plays perfectly into your question. Firstly, the body would need resources to repair itself, such as with proteins obtained from food. Second, if i remember correctly from my CPR training, it only takes around 3-5 minutes without oxygen to get brain damage. This would mean your mage needs to be relatively quick if they want to keep the subject’s memories perfectly intact. Otherwise they might have amnesia or partial amnesia. Finally, if the spell works, the person is no longer dead, they are as alive as they were before they died, meaning they still need to eat and breathe and perform every other bodily function the human body does.

Bonus - Where to get the bodies

When most people think of necromancy, they think of necromancers raising the corpses of deceased solider on a battlefield or raiding graveyards and crypts. However, there are so much more interesting things you could do.

For example, executions. A necromancer might go to a prison and ask the guard if there are any prisoners awaiting execution and, if so, may ask to buy the body. Obviously this would not work as well if they were beheaded, though if they were hung or poisoned you could easily reanimate the body. (Also, a guard may say ‘yes’ and execute a prisoner who wasn’t on the list to get a bit of extra money).

An alternative may be to go to a hospital morgue or a holy site, though they might be more reluctant to hand over the deceased. A thieves guild, mercenary guild or an assassins guild may quite readily hand over bodies though. You could also pay grave robbers to bring you bodies, much like what was done in Victorian London where scientists were dissecting human cadavers to find out how they worked, though this was highly illegal.

Another example would be contracts. Local peasantry or the homeless are famously short on money, something an enterprising necromancer may exploit. A necromancer may go to a local peasant and offer to buy their body once they die, paying them in advance. Whilst this might seem ludicrous and you may think no one would ever do this, you have to remember this peasant may have a large, starving family and no way of paying for or making food. This works especially well in times of famine or war or simply when taxes are raised significantly. (An evil necromancer may pay someone, have them sign the contract and kill them, this works best if if looks like an accident and does not happen immediately after they sign the contract. If the local law enforcement come, the necromancer has the contract proving that the victim’s body belongs to them.)

When someone comes along with a bag of coin offering to buy their body, which they wont be using once they die anyway, it may seem a tempting offer. Its a similar idea to how people donate their bodies to science in our modern world. You have even have this on a larger scale with magical academies making these offers and giving the bodies to their necromancy students.

  • $\begingroup$ If necromancy is "evil" as OP supposes, then necromancers are going to have a hard time convincing the city guard not to arrest them, let alone sell them a body. The same goes for many other "reasonable" options. Traditionally contracts are unenforceable if they involve criminal acts, so buying a peasant's body "legitimately" may be a hard sell as well. $\endgroup$ – Kevin Apr 27 '19 at 22:50
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    $\begingroup$ @Kevin True, but selling the corpses to the necromancers could be seen as the lesser of the two evils. Either you offer them a way to legitimately obtain corpses, or you force the necromancers to take them by force. Whilst the city guard may not be happy about selling the corpses to the necromancers or honouring the contracts, their other alternative is to try and kill or detain the necromancer. This would force them into the shadows, killing people in their beds or in the streets, something the city guard, and local the populace, would be far less happy about. $\endgroup$ – Liam Morris Apr 27 '19 at 23:21
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    $\begingroup$ If you want a real world example of this idea of enforcing the law creating more crime (known as a deviance amplification spiral), look at the prohibition. Making the consumption of alcohol illegal did not stop people from drinking it, instead people simply went to underground bars and moonshiners or you had gangsters bribing the police force to let in alcohol and look the other way, sometimes even with alcohol they were meant to confiscate. Removing legitimate opportunities forces people into deviant careers which, in their case, was illegal bars. In ours, it would be increased murder rates. $\endgroup$ – Liam Morris Apr 27 '19 at 23:28
  • $\begingroup$ What prevents peasants from double-spending their corpses to multiple necromancers? Do necromancers network together to ensure their bargains have a standing? This is abound with issues. $\endgroup$ – John Dvorak Apr 28 '19 at 8:55
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    $\begingroup$ @JohnDvorak The contract would be signed and dated, even if both necromancers had signed contracts, if taken to court the one with the earliest dated contract wins ownership. Another way would be for the necromancer to magically brand the peasant. If another necromancer came along, they would see that this peasant had already signed a contract. Much in the same way livestock used to be branded to prove that a farmer owned it, preventing another farmer from stealing it and bringing it to their own farm. You could also check the deceased’s memories and determine which contract was signed first. $\endgroup$ – Liam Morris Apr 28 '19 at 9:58

Necromancers are doctors.

If you have a society that views any medical intervention as "magical" or "unnatural", then doctors are effectively using magic to prolong life unnaturally, especially, if you consider interventions such as life-support.

You could approach this in one of two ways

(1) the doctor is benevolent, saving lives, but as a result of social beliefs, those saved are outcast, and the doctor is viewed by society as an evil necromancer.

(2) the doctor is manipulative, using medicine to control their victims. This is reminiscent of existing theories about haitian zombies being the result of drug cocktails which induce an artificial coma followed by a hallucinogen which would make them very susceptible to the instructions of the person who had administered the cocktail to the zombie. (Wikipedia)

The only caveat here is that the person never died under our definition in the first place. However, the legal/medical definition of death has changed over time. For example, a lack of pulse used to be a standard definition, but with modern medicine, this definition is no longer adequate. Let your society subscribe to an older definition, like pulse, and be suspicious of the apparent re-vivication of those whose hearts had previously stopped.

Your question specifies no smell or decay, but if you wanted the "dead" to decay, consider medical treatments that do not cure disease, but only slow its progression.


The magic has the power to recompose. The more decomposed the body is the more magic it requires to recompose a body. Thus stamina and skill of the necromancer may play a role in how decomposed a body one is able to revive.

If the recomposed body requires constant addition of magic The expiration date is when the necromancer runs out of stamina or for some other reason cannot maintain the spell because of losing concentration, sleeping, dying. Concentration could be maintained while resting in meditation or necromancers could have the skill to not sleep (this would be unhealthy) to allow longer periods of use.

If the revived one is perfectly brought back: The dead did die for a reason. That reason might kill the revived one quite fast.

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    $\begingroup$ I think recompose is the word you’re looking for, it means the same thing as dedecompose but removes the double-negative and is a lot easier to say. It means to make something composed again, which i believe is what you are trying to explain. $\endgroup$ – Liam Morris Apr 27 '19 at 17:05

I've always assumed necromancy to be the (temporary) animation of dead bodies. This would perfectly fit your requirements.

  • A dead body is just a bunch of bones and organs in a skin. Through the use of magic this mass is given a way to 'defy' gravity, to have a certain amount of force, and (if so desired) is animated to resemble former behavioral modes.
    A good illustration of this would be the armature used for rigging 3d models to animate them:

    Rigged right arm in Blender

    Magical bones are added to the dead body, that can change position within (or, more gruesomely, without) the limitations of the body.

  • Considering you seem to want the dead to retain (parts of) their memory, this will be decisive for the period of necromantic reanimation: the longer the magic practitioner waits, the less brain cells will be intact, and that limit is around three minutes:

    The brain, however, appears to accumulate ischemic injury faster than any other organ. Without special treatment after circulation is restarted, full recovery of the brain after more than 3 minutes of clinical death at normal body temperature is rare source, but?!

    How one would tap into those brain functions is ..magic!

  • The expiration date of the animated 'meatbag' would be either that of the physical deteriorating body (slowly falling apart), or, (un)naturally, its deterioration decelerated by magic, shielding the body from external forces and internal detrimental processes.


Resident demon.

Your reanimated dead are reanimated thru placement of a summoned spirit. This spirit moves into the body and maintains it. It will repair what it can. It occupies the brain and can derive some memories and other things from what is left.

The spirit can only do so much. A body might be too far gone with decay, which will piss the spirit off.

If you have substandard corpses, or want to make something better, it is possible to augment the corpse, or fortify it, or combine good pieces from several corpses either before or after the spirit moves in and takes over.


"Realistic" necromancy would be restoring all the basic functions of the body, which would include most organs and tissues found in a living body. So no zombies that don't need to breathe, eat or whose only essential component is the brain. I would argue that the end result would be a mostly normal human being, perhaps one that would rapidly deteriorate without frequent maintenance from the necromancer by way of manually tuning the various organs, maybe because once returned to life the body doesn't really "know" how to properly maintain itself in the long run.

  • $\begingroup$ That kind of necromancy should happen extremely fast. Limbs can keep from six hours to days before reattachment with modern medicine, but I think stomach and intestines will start rotting almost immediately. $\endgroup$ – Cumehtar Apr 27 '19 at 15:48

Given what you said about not having souls and such, the only way Necromancy will work (or at least be evil) is if it's the more gruesome mindless kind.

Let me explain, in a society with absolutely no chance of an after life, there would be a great drive to prolong ones life as long as possible. Even without that, there would be the same drive to preserve ones life in the case of illness or injury. This is only natural behaviour but without the comfort of religions and afterlife gives.

So if your Necromancers can preserve the mind and the body of the dead, they would of course be highly valued by such a society. Which obviously makes them non-evil.

Now however if they cannot preserve the body or the mind, well that's a different story.


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