In my fantasy novel, magic is a natural part of the world. It is not some mystical force shrouded in mystery, but rather backed by science (though only I, the author, know it's true workings).

In my world, magic is a force that by its nature changes living cells. It is similar to radiation, but different in the respect that it changes what the cell does, usually in a beneficial way. For example, if the cells of an eye were exposed to magic, the magic might make the eye also see infared light (I don't know if that's biologically possible, but it's an example).

There are those in my world that can control the change worked by the magic. (They can force the magic to make the eye see infared light. They can also use magic to make that same eye go blind.)

Here's my question. Using this magic, what would be the most effective way to kill a normal human? What would be the most effective way to temporarily paralyze/incapacitate one? If possible, the effect has to be near-instantaneous, as this magic would be used in combat.

Other questions, using this magic (the above is the main one, but if you can answer these too, that would be great):

Could something, like a clump of grass or the fur of a wolf, be set on fire, simply by changing what the cells do?

What would be the most efficient way to produce light? (Bioluminesence, fire, etc. A magic user could in theory just alter the cells of his hand to be bioluminescent, right?)

Could skin be made fireproof?

How would healing with this magic work? Could it be instant, faster than natural, or have no effect? Could magic keep the wound clean?

  • 1
    $\begingroup$ If you stop the question before you add all the other questions it would be good, but you asking 8 questions and I think they could be broken down to 3 Stack Exchange questions $\endgroup$
    – bowlturner
    Commented Mar 25, 2015 at 2:11
  • $\begingroup$ I put them all in one because they all use the same magic. If you think asking them individually would be better, I can definitely do that. I thought people might want them all under the same heading. $\endgroup$ Commented Mar 25, 2015 at 3:24

5 Answers 5


Question 1: Infrared/UV sight: Possible. As stated above, there are animals that can see in both spectrums, though snakes actually use a different organ than the eye.

Question 2: Effective ways to kill: Severe nerve connection from the brain. This works well because you are altering very few cells (comparatively) to any other method. And the person stays alive for a bit, meaning if you used magic, you can reverse it

Question 3: Incapacitate Enemies: There are a host of ways to do this. The safest and fastest means would to play havoc with their sense organs (including balance).

Question 4: Igniting biological matter: Oh heck yes. Your body is constantly breaking apart molecules for energy. Thankfully, there are gates on that process, or else we would literally burn to death. Remove the proper safeguards in a fuel-burning cell and watch the fireworks.

Question 5: Efficient light: When oxygen combines with calcium, adenosine triphosphate (ATP) and the chemical luciferin in the presence of luciferase, a bioluminescent enzyme, light is produced. This is how fire flies do it, and they are almost 100% efficient at making light.

Question 6: Fire-Proof Biology: Totally possible. If you think about it, all you need are scales. The problem is that even scales heat up and can burn the flesh underneath, so you would need to build an efficient cooling system under the scales.

Question 7: Healing: Sort of. Increased healing speeds and even regeneration of limbs would be possible, but it would still take a long time and would require massive amounts of food and sleep. Instant healing would never happen with magic that can only affect cell makeup and function.

  • $\begingroup$ Excellent answers! I do have one question: if the nerves to the brain were severed, how long would a person stay alive? If you reversed the process, would there be no neural damage? $\endgroup$ Commented Apr 8, 2015 at 21:53
  • $\begingroup$ If you were careful to hit the correct nerves, it could potentially put the target in a permanent vegetative state. Reversal is simple, but basically the only side effect would be little to no intact memory of the vegetative state time. However, if you hit any of the nerves related to the heart, it will kill in seconds, lungs will kill in minutes $\endgroup$ Commented Apr 9, 2015 at 6:18
  • $\begingroup$ So if I hit the correct nerves to induce a vegetive state, and then reversed it, absolutely everything aside from memory of the state itself would be intact? (memories, for instance) If so, this is great! $\endgroup$ Commented Apr 9, 2015 at 17:13
  • $\begingroup$ Totally, that being said, if the more precise the procedure, the longer it takes, avoid using this in a direct confrontation as it would require extreme precision $\endgroup$ Commented Apr 9, 2015 at 20:05
  • $\begingroup$ Hi, wouldn't the ability to alter someone's brain be a skill that is mastered after [insert a long time] of training? If not, what are the repercussions of hundreds of lvl1s being able to paralyze each other at will? $\endgroup$
    – Traveler
    Commented Apr 19, 2020 at 2:21

The human body is a complicated set of interacting systems, with most of them needed for everyday motions, and especially needed for combat. Interrupt any one of these, and you can take a person out of a fight! Choose one system, alter a process very slightly, and watch the person succumb to their new ailment. This is especially true for the following systems: circulatory, nervous, skeletal-muscle, and respiratory.


You're going to need a good definition for efficiency in killing. Do you mean quick or painless? Do you simply mean the method of killing which expends the least energy? I'm going to an amalgamation of all three. Not to compete with the list which bowlturner started, I will simply add to it:

  • Prevent Neurons from firing. Seal up the chemoreceptors on neurons, or simply deform them, and even your most hard-boiled adversary is reduced to a vegetable or even just mere warm matter.

  • Turn muscle fibers into the cooked version of themselves. This works especially well for the heart.


These are specifically non-lethal, but will still harm individuals.

  • Activate (or disable) the voltage dependent calcium gates in people's cells. This will cause their muscles to tense up, rendering them useless until their calcium gates restore equilibrium. The alternative is just to make their nerves fire randomly or all at once.

  • Change their eyes to be super sensitive to visible light. It effectively gives a flash-bang type effect. Yes, this is technically an enhancement, but few people will be well trained enough to adjust. When people first get glasses, for example, they often have trouble with visual tasks for a day or so until their eyes adjust. (I know I had trouble.)

  • Stiffen the or remove hairs of the inner ear. This denies your opponent their senses of hearing and balance, but can be undone with regeneration. More on that below.

Other Questions

Snakes see in infrared. Bees and birds see in UV. It can be done, and nature does it for different creatures. You just need to add the correct receptors.

Yes, setting things on fire can be done. You simply need to hit ignition temperatures for that thing. Spontaneously and only be modifying current cells? I doubt that. You could increase the surface area of the items to lower the heat needed to burn that thing. I suppose you could force the cells to produce something that burns when in contact with air, but that is super dangerous!

The best way for a creature to non-destructively produce light via modification of an organism is bioluminescence. Of course, if your magic is in the business of modifying eyes, why not just give people tapetum lucida? Their eyes will shine like a cat and can see much better in the dark; certainly much better than if they shine like a beacon.

Can skin be made fireproof? If you could convince the skin to exude a mucus or some other non-flammable substance, this can be done. It should be noted, however, that everything burns, just not at the same temperature. Anyways, a non-flammable mucus can have the benefit of providing a layer of insulation between the skin and the flame. I suppose you could have thick scales on your skin, but then that really isn't skin, is it?

Can magic be used to heal better? I do not know; it is your magic. If this magic can only change people's biology, then yes, it can help heal. For instance, if you increase the number of or stimulate the production of stem cells, regeneration becomes doable. Is it faster than normal healing? No. It still takes a while, but the benefit is that it happens, instead of remaining a dream. The creature regenerating that limb still needs energy to regenerate; it means you would need to eat a lot of food while regrowing a limb.

  • $\begingroup$ Killing: I'm looking for the fastest/easiest method, something that could be done in a second in a fight. Painless doesn't matter. Incapacitate: If the hairs of the inner ear were stiffened, would that damage them, or could they similarly be 'unstiffened' with no lasting effects? Also, how unbalanced would a person be? Would they be able to walk at all? Thanks, these answers are great! $\endgroup$ Commented Mar 25, 2015 at 6:12
  • $\begingroup$ @TommyMyron: No simple temporary change of internal physiology will kill someone under a second. You might stop the heart but it has a good chance of restarting on a small impulse (like falling to the ground). The fastest I can think of which would incapacitate within some 10s, kill in 30 or so, would be fine muscle control: bring wrist to mouth, bite through veins. Of course muscle control can be used for other purposes like the enemy stabbing themselves or jumping at the floor headfirst. $\endgroup$
    – SF.
    Commented Mar 25, 2015 at 6:39
  • $\begingroup$ Hmm... as I understand a heart attack, it happens pretty fast (mind you, all I have to go off of are movies). If you stopped the heart, wouldn't it make them stumble or something (aka, render them helpless), and then kill them under 10 seconds? The magic can alter the cells, it can't control them (so no biting through veins unfortunately). $\endgroup$ Commented Mar 25, 2015 at 17:14
  • $\begingroup$ @TommyMyron I'm not sure. It depends on how long it takes for individual cells to suffocate and run out of oxygen. $\endgroup$
    – PipperChip
    Commented Mar 25, 2015 at 18:54
  • $\begingroup$ Along the lines of the healing question - what if the wound is just a cut, say a deadly gash in the arm in or something. Could the flow of blood be halted just by altering the cells? Could you seal the wound? $\endgroup$ Commented Mar 29, 2015 at 16:56

Flame on!

Can a clump of grass or a wolf be set on fire by changing what the cells do? Absolutely. Using your "magic" one must simply alter the cells to secrete acids or other compounds which result in a violent chemical reaction.

Example: To defend itself, the bombardier beetle produces a spray which is a combination of hydroquinone and hydrogen peroxide. Someone who wields your form of magic may be able to manipulate plant or other cells in this manner.


I'm just going to answer the first part of the question, about using magic in battle for 'efficient' killing.

Making the heart stop would be very fast. Stopping any blood going to the brain, blood vessels constricting. Stopping all electrical signals in the brain(body) Neck muscles contract to the point of breaking the neck. Blood produce a poison/neurotoxin paralyze the diaphragm

Even narrowing down the question I still made a list...

  • $\begingroup$ If the heart were stopped, how long would it be before the individual died? Would they be incapacitated immediately (pain, unconsciousness, etc.). Also, if one were to change blood cells in a small area (say the hand) into some form of deadly poison, how fast could that poison be circulated to a critical area, and what kind of poison/toxin would it have to be to have immediate effects? It doesn't need to kill immediately as long as it incapacitates right away, and kills later. Poison is a great option if it is fast-acting. $\endgroup$ Commented Mar 26, 2015 at 0:04
  • $\begingroup$ @TommyMyron I think if the heart stopped they could be conscious for several minutes but it would likely be terribly painful immediately, unless they were already in the middle of an adrenalin rush, and with out the heart beating, even that would dissipate very quickly. $\endgroup$
    – bowlturner
    Commented Mar 26, 2015 at 1:08
  • $\begingroup$ Sounds great (well, no, it sounds painful, but you get my meaning)! What about the poison though? $\endgroup$ Commented Mar 26, 2015 at 1:28
  • $\begingroup$ @TommyMyron depends on the poison, nerve agents are the fastest acting so that is what you would want, most of them cause paralysis and the others cause extreme pain. $\endgroup$
    – bowlturner
    Commented Mar 26, 2015 at 1:37

The most efficient way to kill someone would simply be to stop every cell in their body from working (just get it to self-destruct). This would kill them more or less instantaneously.

As for incapacitating them, you could (as most people sugggest) mess with thier senses, or get make their body produce an aneasthtic.

Healing? Well, if you remove the limits of homeostasis and raise the metabolism and increase cell division, you could heal massive injuries in a few hours. You may also want to give the injured person the ability to photosynthisise to help meet the energy requirements. Fine control would be needed to avoid cancer (from all the rapid cell division). Also, rasing the metabolism too much will kill the cells.

Combustion? Tricky, but possible. altering cells so they can survive extreme tempuratures, like some micro-organsisms (e.g: water bear), and then increasing the metabolism until the heat causes combustion is one way, but producing flammable compounds might be easier.


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