A necromancer decided to raise an army of zombies to attack the neighbouring kingdom. It's a relatively small and decentralized kingdom, about the size of Denmark. In this world, zombies cannot infect zombism to living beings. But getting bitten can still inflict other diseases like rage. The only way to create new zombies is with necromancy, a dark form of magic known to only a few.

Assuming the necromancer has access to about 10 000 fresh corpses to start the invasion. Once the invasion is started, he will not be able to create new zombies for a while because it's exhausting and he is busy waging a war. After a while it will become possible the crate new zombies to replace the decayed ones by using the fresh corpses of the countryside.

Zombies are slow and dumb but do not fear danger. Zombies do not suffer and move even if you cut their head off. Limbs that are severed or damaged enough will stop moving. If the body parts become too decayed, they will stop responding to magic. Zombies will continue to move unless all the limbs are dead or if you hack the torso in pieces. I believe the decomposition rate might be faster than on a corpse lying still because the zombies are moving. The magic makes the zombies move but it does not slow the decaying rate.

Considering the decaying rate of the human body, is this kind of invasion even possible? How long will it take before the initial army falls into pieces by itself?

Are there any natural techniques or type of environments that would slow down the decaying process?

  • 1
    $\begingroup$ This one is going to be tough to answer without better understanding the magic that gets them moving in the first place. I mean, even assuming it's possible to reanimate the corpses, how are they going to overcome rigor mortis? $\endgroup$ Sep 22, 2015 at 15:15
  • $\begingroup$ @DaaaahWhoosh rigor mortis is only a problem for a short period of time. $\endgroup$
    – bowlturner
    Sep 22, 2015 at 15:17
  • $\begingroup$ where do you get 10000 fresh corpses in a medieval world? $\endgroup$
    – Oldcat
    Sep 22, 2015 at 17:07
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    $\begingroup$ @oldcat You liquidate a medium-small city. The Great Plague (1666) killed an estimated 100,000 people, almost a quarter of London's population. Or, do two zombie-making rituals; first one (small; say 500) that makes enough to attack a city, second to take the city's corpses as your main army. Probably blown out your magic by then, though (ie: upper limit could be 10K - which means world beats Necromancer by mobilizing, since he has an upper-limit). $\endgroup$
    – user3082
    Sep 22, 2015 at 19:49
  • $\begingroup$ @user3082 The plague did it over a considerable time period, so they would not all be fresh. And without his zombie army, how does the sorcerer kill the people? $\endgroup$
    – Oldcat
    Sep 22, 2015 at 21:38

6 Answers 6



If the body can walk headless and he have a decaying body, we can assume that it is not 'live', but walking only with magic. With this scenario, it is possible to use good old mummification. This will boost your time to use the corpses, but will need someone or something do do the mummification process. If you can use magic on that, would be wonderful. The corpses will still decay, but on a pretty low rate.


A good environment to start the invasion is a very cold one. Your necromancer should wait untill the winter comes, so he can use the bodies on a even slower decayment rate combined with mummification. The downside will be, probably, slower Zombies.


You don't even need the cold environment if you have a good mummification process. With that, your Zombies could live hundreds of years! If your magic need to account for the weight of the body, with less weight they will be faster.


When buried six feet down, without a coffin, in ordinary soil, an unembalmed adult normally takes eight to twelve years to decompose to a skeleton

The reason this happens is that you've cut off access to certain types of insects, namely flies (blowflies and flesh flies)

In the absence of scavengers though, it is the maggots that are responsible for removal of the soft tissues.

When a decomposing body starts to purge, it becomes fully exposed to its surroundings. At this stage, microbial and insect activity reaches its peak, and the cadaveric ecosystem really comes into its own...

...fire ants made little sponges out of dirt and used them to fill in the cut and stop up the fluid.” The ants monopolised the wound for more than a week, and then it rained. “This washed the dirt sponges out. The body began to bloat then it blew up, and at that point the flies could colonise it.”

Depending on the times, circumstances, and other variables - such an invasion is possible. It depends how effective your zombies are in putting down human defenders, and how quickly you can put down the defenders before they start to figure out (evolve) solutions to fighting your zombies.

How long your zombies will take to fall apart ranges from over 58 hours to years, depending on whether you salt them, pickle them, mummify them, put anti-fly poison in them, etc. 58 hours after death, is the earliest time that microbes have been found in all organs of the body. The biggest problem is once the microbes have caused skin slippage and bloating to occur, then the flies really get going (see above).

Denmark's largest distance is 250mi. Average walking rate is 3.1mph. Which means your zombies can walk the longest distance in 80 hours. Ignoring, of course, the numerous islands that are part of Denmark, mountains, etc. Depending on how fast you put down the defenders, your zombies could liquidate (heh) the nation prior to liquefying themselves. :)


Taking your second question first.

Arid and/or cold territory would greatly extend the useable timeframe. So would having access to salt flats where you could send your zombies to cover themselves in salt for a bit of seasoning prior to your campaign.

For your first question.

28 Weeks Later talked about the interval since 28 Days Later, where the majority of infected had died off. Of course their version was super rabies rather than being undead. There would be rot and decay, but there would also be a massive attack by carrion eaters. Vultures and Crows would be constantly circling. Ants and other insects would take a huge toll on the army. If there is something like Army Ants in the region, swarms would quickly decimate slow moving Zombies.


At first I was thinking soak them in rum to kill the bacteria, and while that would work it would also make them an easy torch, a quick match would reduce them to ashes. (though it might explain their wandering gate and unintelligible mumbling!)

So my next one would be to dry them out. Remove all moisture from the bodies, turn them into people jerky. It will slow the decay to almost nothing (look at mummies!) It will also make the body more resistant to cutting attacks! Jerky/leather is much harder to cut than flesh with normal moisture content.

Edt: Oh, instead of rum you could pickle them! That is another preservative that kills off decomposing bacteria! They will all have a very distinctive smell too...

  • $\begingroup$ Mmmm.. Pickled Ladies Fingers, my favourite! ... What do you mean it's not okra? $\endgroup$
    – Joe Bloggs
    Oct 28, 2015 at 10:17
  • $\begingroup$ Actually, the alcohol evaporates in a matter of minutes at room temperature. So no easy burning. Plus, virtually all the rum will simply run off the zombie as soon as it stands up. If the zombies are swathed in rum-soaked mummy wrappings a la the old mummy movies the torch option gets better, but in part the wrappings will protect the zombies. Evaporation of the alcohol will tend to cool the zombie flesh as well. $\endgroup$ Jun 7, 2017 at 0:47

Ok so there are a few factors to consider here

Climate: bodies decompose faster in warm wet weather. If the conditions are right the body can decompose to an unuseable grade in less than a week. Moisture is key. Dry deserts have been known to preserve bodies for decades same with frozen terrain.

Preservation: There are plenty of preservatives that could be applied to a body to desicate and or preserve it. Having your wizard command your zombies to take a bath in an arsenic solution after being risen would be a good way to preserve them longer as well as make them toxic to the enemy. There are plenty of embalming techniques to consider along these lines. A wax arsenic compound has been applied to preserve tissue so far indefinitely to almost lifelike appearance.

Answer: attacking during winter would be ideal (GOT har-har) as that would be a more conducive environment. Your mage could instruct his zombies to preserve themselves which would increase their lifespan. If a natural solution to preservation is absolutely necessary then try a fungus that absorbs the moisture and produces a desiccating and preserving enzyme.

  • $\begingroup$ Your fungus brought me to another idea: Penicilin is produced by a fungus, so purposely infecting your army with this could stop all bacteria-based rotting. (They would then be rotting bc of that fungus, but that could just be surfce-level $\endgroup$
    – Hobbamok
    May 22, 2019 at 11:36

If you didn't preserve them in any way ie. feeding them yoghurt, they would rot in a few days. And they probably wouldn't be that dangerous anyway, because their motor system would rot with the rest of them.


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