In a parallel universe people born with high affinity can apply magic directly on the material world, you can use magic to harm others at the expanse of risking magical feedback similar to the amplification of sound through microphone. For example, when you hurl a fireball at a subject, there is some uncertainty that the fireball will detonate before leaving your hand and the explosion gets worse when you attempt more potent magical spell. Suppose magic don't care about cause and effect, and it has infinite range then why there is no instant death spell which includes magical feedback despite numerous attempts?

Magical feedback explained: To manipulate magic, one has to siphon the magical energy from the surrounding and usually the amount depends on the user's affinity, then to materialize the magic energy into a hot plasma such as a fireball one need to make a hand sign which serves as a catalyst to strengthen and contain the plasma. But be cautious as there is an uncertainty for catalyst to produce magical feedback without warning, levitation do not requires catalyst so there is no feedback but people still get killed from falling at height also note that catalyst only apply when user is applying magic beyond oneself aka action at a distance ;D

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    $\begingroup$ As written, this is a bit difficult to follow. If spells occasionally backfire, then maybe no one wants to use instant death spell, because there is a chance it will kill the caster? $\endgroup$
    – void_ptr
    Jan 25 at 3:02
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    $\begingroup$ I'm having trouble following this too. The "feedback" principle is somewhat understandable as stated, but I'm not seeing the connection with causality violation. Are you suggesting that a "magician" can shoot a fireball into the past to attack a target at the location they "were" at, but can't do the same with an "instant death" spell? $\endgroup$ Jan 25 at 3:07
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    $\begingroup$ The uncertainty in the feedback principle is slightly clarified, but I'm still not seeing the connection with causality. The cause and effect appear to be quite clear - 1. collect (siphon) magical energy; 2. materialise effect (plasma?) with a gesture (catalyst); 3. stuff happens (uncertainty re whether the stuff is what was intended or not). For causality to be an issue, it would mean that to at least one observer those steps happened out of order - for example, a fireball went off, then a hand gesture was made, then energy was siphoned. $\endgroup$ Jan 25 at 3:48
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    $\begingroup$ because "instant death" is an absolute, and even 0.000001% of "instant death" is "instant death", so every "instant death"-spell ever discovered was an "instant suicide"-spell as well $\endgroup$ Jan 25 at 8:21
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    $\begingroup$ So if your affinity is not that high, you probably prefer casting a suicide spell, since the chance of that backfiring and killing an opponent is higher than it killing you yourself? $\endgroup$
    – Joachim
    Jan 25 at 10:04

6 Answers 6


The spell hits a germ.

If you walk into a phonebox, then you account for less than 0.000001% of the living beings inside the phonebox. There are bacteria in your stomach as part of your digestive system; there are mites living inside your follicles; and various other ittybitties all over the place. That means an instant death spell cast at a person tends to work and kill SOMETHING. But usually it works on a micro-organism with no visible consequence. Modern scholars have no conception of micro-organisms being on every surface, and the Instant Death Paradox has confounded them for centuries.

Note: The question never says what an "Instant Death spell" is. In the answer I consider it to be a spell which kills a living being without any other physical effect like turning the body into mush, chopping off the head or liquefying the brain.

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    $\begingroup$ Although it is only slightly connected with original question, still a brilliant idea! $\endgroup$ Jan 25 at 9:34
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    $\begingroup$ I don't understand the question beyond "spells have a chance to go wrong. Why no instant-death spell?" $\endgroup$
    – Daron
    Jan 25 at 11:22
  • $\begingroup$ Wouldn't this apply to any spell? Like "Freeze", and it seems to fail, but actually something has frozen in the surface of the target. $\endgroup$
    – Seretba
    Jan 25 at 12:17
  • $\begingroup$ @Seretba The difference is you cast Freeze on an area of space that contains the person or thing you want to freeze. If you miss the spell then the area just ends up somewhere different. With the InstaDeath spell however you must target a single living being. So if you miss then you end up killing a different living being. $\endgroup$
    – Daron
    Jan 25 at 12:53

Instant death spells are common, so actual instant death spells are bad

There are plenty of instant death spells. Shooting you in the brain with a bullet kills you instantly. Setting your whole body on fire effectively kills you instantly. Cutting your head cut off kills you instantly. However all of these are relatively low power in relation to what a instant kill spell would be.

An instant kill spell feels like it should kill the person without any exterior effect, unlike a bullet or a fireball. So you need to create a high power, localized spell, that possibly targets individual cells, that applies small amounts of heat and force intelligently. This is extremely potent magic. As a result, the chance of it backfiring is basically 100%.

Because of this, no one uses or attempts this kind of high level magic. It is easier to use a less powerful spell that has a chance of actually going off, instead of using a spell that basically is a suicide spell.


There probably is

After all, mages turn up dead all the time don't they?

The trouble with any spell is that it takes practice to cast it right. And then there's the feedback. If the spell is instant death, then the feedback is likely to be instant death. Since instant death is a binary effect, dead or not dead, there's no way to build up the power gradually like there is with e.g. a fireball.

So while the spell theoretically exists, somewhere in the ether for research mages to discover, anyone attempting it is likely to end up dead themselves before ever successfully casting it.

Does a spell exist if nobody can cast it?

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    $\begingroup$ Rather amusingly suggests the idea of a spell of "Petit Mort".. Which I'm sure is exceptionally popular among student wizards. $\endgroup$
    – Ruadhan
    Jan 25 at 12:49

Misfired Spells Actually Happen a Millisecond Before the Casting is Done:

Magic is inherently unstable, but it must follow its own internally consistent rules. For a spell to happen, there must be a chance that it malfunctions by activating during casting. The magic warps time (but only by the slightest fraction of a second).

Magic disrupts causality, so a fireball that detonates at the hand of the spellcaster actually occurs while the caster is finishing the spell. Therefore, it detonates IN the caster (or at least their hand). But in that tiny increment of time before the fireball blasts the wizard, the spell is still completed.

For a death spell, the spell causing the death of the caster is instantaneous. Therefor, if the spell misfires, the caster dies before he actually finishes casting the spell. At that point, the spell never happens.

If the spell can't misfire, it similarly can't be cast. The paradox of the misfire cancelling itself out precludes the spell being able to function, since there must always be the chance of misfire.


Newton's Third Law

To any action, there is an equal and opposite reaction. A hypothetical 'instant death' spell to directly snuff the life of another out, without a physical mechanism (such as your levitation example), can only be working by directly attacking the soul of the person.

The problem, of course, is feedback. The spell's feedback would affect their own soul, wrecking them. More importantly, it's not possible to complete casting such soul-affecting magic before feedback disrupts the ability to finish whatever you were trying to cast. Anyone trying burns him/herself out.


The spell is successful

People don't understand the spell well enough. They use it to effect, but only kill off one cell of the body.

The difficulty of other spells at a distance

You might see a fireball generated at the location of the enemy as an instant death spell.

Humans rely on their senses to get a feeling if the space. With spells this goes quickly beyond our senses. If you stand outside a house, how can you reliably target a single person somewhere in the house? What about an exact kilometer away from you? Or maybe just beyond the horizon? You'll need to extend your own consciousness to this place magically and then cast the spell. This has the same problem, as you can't just project your consciousness to the right place. So you need to move your consciousness to the place before you can do the spell.

This takes time, requires multiple spells, skill and gives opportunity to disrupt these spells. That is easily a too high requirement.

Humans are too flawed to instant kill at a distance.


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