This is a sort of follow-up to my Way to sacrifice a human with little to no physical damage question.

In my fantasy world, there are magic users that have to power to insert their consciousness into another human body. However, the body must be dead in order to do so. When the consciousness, or "soul" as it is in my world, is inserted into the body, the body will have approximately three days to live before it decomposes under the magical influence, however. During this time, however, the bodies will be completely alive, with seemingly no difference (as long as they are killed with minimal damage). Also, this transfer does not require a ritual, it is only necessary for the magician to come in contact with the body, although it does tire them out. The magic user that inserted their soul into the person does not "control" the person or reanimate them into their previous state, but rather the body has the same consciousness as the magician that created them, meaning they would react to things the same way the original would have the same morals, moods, etc. However, these bodies can all communicate together telepathically, but the original magician is the only one to receive the communication, kind of like a human telephone tower, however, the transfer must be manual, but then again it is the magician's mind, so if data needs to be transferred, it will be.

So, with these in mind, what possible uses would this kind of power entail? Remember this is a fantasy world with technology equivalent to that of Imperial China, so they would suffer from regular medieval problems (food, water, shelter, military, entertainment, etc). Also, note that these magicians can train to handle multiple streams of information at once as well as insert the souls more efficiently as to not tire out so quickly.

Leave any question below.

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    $\begingroup$ You basically have what is a physical botnet. $\endgroup$ – A. C. A. C. Nov 10 '17 at 22:08
  • $\begingroup$ @A.C.A.C. Kind of, but they only last for three days. $\endgroup$ – Unhappymarshmellow Nov 10 '17 at 22:09
  • $\begingroup$ Does it have to be a recently dead body? What about the body decomposition? $\endgroup$ – Olga Nov 10 '17 at 23:45
  • $\begingroup$ @Olga It can be anybody, but just remember that these people will probably need to do normal things, so a decomposed body would not be ideal. Also, the more damage done to it means the time before it becomes useless accelerates. $\endgroup$ – Unhappymarshmellow Nov 10 '17 at 23:48
  • $\begingroup$ @Unhappymarshmellow, is there some magical healing of the body if it is damaged or decomposed? Your question states that 'the bodies will be completely alive, with seemingly no difference'. $\endgroup$ – Olga Nov 10 '17 at 23:56

Considering time limitations and obvious scarcity of resources (human bodies), the most likely uses that I can see are espionage/investigation, learning (kudos @akaioi), and dirty jobs that a magician does not want to do with their own body. I am thinking about something similar to clones in the Dark Matter series, except the memory transfer is immediate and the clone does not have a physical resemblance to the magician.


Spying is an obvious use. You just need to obtain a suitable body and you are good to go for three days. However, a magician should be careful not to expose itself, since their personality is different from the original body 'owner'.

Mental cloning will not be possible to use for an extended espionage network. It will also not be possible to use it for long-term projects. Moreover, since a magician has to be in a town or within a short travelling distance from it, it might not be practical to use this magic at all except in extreme circumstances. Any well-organised security group will keep tabs on all magicians known to be capable of mental cloning.

Investigation tasks are akin to espionage, but probably involve lower risk of exposure since a magician does not need to pretend to be someone they are not. Some kind of identification codes can be used to prove to informants that yet another body visiting them is indeed possessed by a specific magician.


One mind is good, but many are better!

All learning will be facilitated and sped up. However, the effects will depend on a type of knowledge a magician is trying to acquire.

Knowledge requiring muscle memory

Skills, such as fencing, dancing, crafting, heavily rely on muscle memory, which can be described as a brain rewiring to increase the efficiency of a neural response. It is a physical process that must happen in the brain of a magician. There is no workaround for it. Observation and understanding of the underlying principles facilitate learning, but in order to acquire a functioning skill, a learner has to practice it. Therefore, do not expect your magicians to become martial arts specialists without actual sparring and training.

Theoretical knowledge

While the acquisition of theoretical knowledge also involves rewiring the brain, a trained magician should be well-prepared for processing and memorization of higher volumes of information. In fact, it must be a part of their training in the first place.

Mental clones will function as 'second (third/fourth/etc) selves' who will collect, process, and dump information into the magician's brain. They also can be used for brainstorming or experimental work. A mental clone will also be an indispensable fact-checker and devil's advocate (if they share memories of the original).

Dangerous/Unpleasant tasks

Clones also can be tasked to do something potentially dangerous. For example, they can be sent to negotiate with criminals, retrieve dangerous substances, or travel to unsafe places.

If a magician can secure a steady supply of bodies, they can implement a division of labour in the house. The specific details are up to a magician. But for example, a clone might be running errands or doing research while thу magician is attending a formal ceremony in the palace or travelling.

Unlikely uses

I do not think there is a potential for

  • armies or anything that involves a lot of dead bodies;
  • long-term projects unless they are done in a close proximity to a magician who also has a good and reliable supply of bodies;
  • long-distance communications or projects that do not involve a magician travelling;
  • anything that relies on special skills that a magician does not possess (assassinations, fighting, hunting, and so on);
  • impersonating someone when they are in their own environment unless it is done for a very short time.
  • $\begingroup$ Another possible use is "parallel computing" - with enough clones you may simultaneously explore all possible solutions to difficult theoretical problems, and just see who comes up with the most successful result. $\endgroup$ – G0BLiN Nov 12 '17 at 12:51
  • $\begingroup$ Also, re:long distance communication - two neighboring kingdoms (2 days travel) can regularly exchange clones, so that each king has a clone that can transmit instant messages to a magician at the other king's palace - as long as they send out a new clone every day, there will always be one ready to serve (and as a bonus, they scout the countryside during transit). This concept can be extended to much longer distances using "relays" - midpoints with magicians sending clones to both side and transferring messages to their neighbors' clones... $\endgroup$ – G0BLiN Nov 12 '17 at 13:02
  • $\begingroup$ @G0BLiN, I think that relays might turn into a broken telephone. But overall it sounds like a good idea. Although, where all the bodies are coming from? $\endgroup$ – Olga Nov 16 '17 at 15:23

With only a 3 day window, I would think that this would be something used to "clean up loose ends." Cleaning up business deals, saying "good bye", and dealing with family matters is about all someone could do in only 3 days. In fact, after a death, it usually takes months for a family to "get back to normal"; which means dealing with funeral arrangements, financials, and possessions are dealt with, not that the emotional stuff is clear.

I would suppose this is expensive, financially, so only royalty and the Really Rich would be able to afford something like this. However, a resurrection could be sponsored, but probably in only rare cases. I can also see someone volunteering to be a spy or assassin, as @AndersSandberg suggested, if it would paid for by the royalty or Really Rich and would set up their family financially for a Long Time.

I would assume that the spirit wouldn't just "hang around" waiting for a body and that it would be time sensitive for the transfer. I would also assume that the spirit wouldn't be able to resume it's own dead body. These conditions would just make it too easy for all kinds of things to take place. If you want easy, though, by all means! I won't judge.

BTW, I used "spirit", since (to me) that's a more generic word than "soul." Soul implies the Christian version of spirit. Making that distinction may mean getting getting or losing non-Christian readers, as they may find it "too religious" for them. It's your story, so it's your choice. I just brought it up as something to think about.

  • $\begingroup$ Note that the resurrected people will not be the person they once were, they will have the consciousness of the magic user, so any after death ordeals would not really make sense. $\endgroup$ – Unhappymarshmellow Nov 10 '17 at 22:55
  • $\begingroup$ Ah, I understood it that the magic user was transferring a recently dead person to another body. Oops... Sorry. $\endgroup$ – computercarguy Nov 10 '17 at 23:45
  • $\begingroup$ It's all good :) $\endgroup$ – Unhappymarshmellow Nov 10 '17 at 23:46

Apart from the assassins and spy rles mentioned earlier, they'd also be useful for communications, they're living shortwave radios in a medieval world. Battlefield comms would be a great use, the body is expendable and replaceable after all.

Secure couriers is another use. A clone is sent from City-A to City-B to deliver info. The magic user is given the info in City-A only when the clone has established contact in City-B. If he gets intercepted before contact is made then he knows nothing to reveal to the enemy.

Basically anything that involves moving data would be a potential use for the clones, long range scouts in your army? Food / poison testers.


Most obviously, you have a fairly expendable body. Perfect for dangerous tasks like firefighting, exploration... or assassination. Or being an army. A temporary army, but potentially very well coordinated.

Also, since the body is somebody else's originally, it is perfect for espionage and cons.

  • $\begingroup$ But remember, people have to die in order to insert the soul inside, so I don't think the populous would be hunky-dory with hundreds of them dying so they can be used as soldiers for three days. But theoretically, yes, this would work just fine. $\endgroup$ – Unhappymarshmellow Nov 10 '17 at 22:22

Have each clone kill 2 people before they die and infect them. After about a month, you will have an army large enough to make you King of the world.

  • $\begingroup$ Only the original could infect them, and then again they only last for three days. And also check out the question I followed up on, just killing simply killing them takes longer if you want it to stay for the three days. $\endgroup$ – Unhappymarshmellow Nov 10 '17 at 22:56

Lots of great answers here! Very practical. However, human nature being what it is, I think we're overlooking some very likely uses of the clones...

  • "Research" into risky sex, drugs, and rock-and-roll scenarios

  • Clone could be sent on risky missions (crimes, assassinations) while the original or another clone provides an alibi

  • Investigation of near-death experiences. At what point does the soul get contacted by [spiritual beings of choice]? What does death "feel" like? And so on

  • Temporary workforce to meet important deadlines. That scroll has to be copied by morning! Similarly, if you need more spellcasting power than is available, you could boost your magic pool by cloning

  • 5-day weekend

  • If a magician is to be executed, he might be wise to send a clone to the actual event


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