Consider the situation where a subset of the population in modern times has a power that allows them to consume their life to temporarily increase their speed and/or strength. In a fight, what weapons would they use?

Details about the power

The power works by removing time from the end of a person's lifespan equal to the number of copies of them it would take to do the thing, either serially or in parallel multiplied by the length of the activity. For example, if someone with this power is walking at a pace where it takes 20 minutes to go 1 mile and wants it to take 2 minutes instead, it would take 10 of them to cover the mile (the original plus 9 copies). Thus, the lifespan consumed would be 18 minutes (2 minutes per copy times 9 copies). Similarly, if someone can ordinarily lift 50 pounds and wants to lift a small car (~2000 lbs), it would take 400 of them to do so. A minute of walking around carrying a car would consume 399 minutes (399 copies times 1 minute).

Speed and strength increases require separate copies. So picking up a small car and carrying it as far as one could normally carry 50 pounds in 5 minutes in a minute would consume 19999 minutes of lifespan. It takes 20000 people to cover the given distance in a minute with the load, so there are 19999 copies.

The upper limit to the speed and strength increases is the amount of lifespan available. At any speed, the person can still perceive the world around them normally.

If someone attempts to do something and doesn't have enough lifespan left to do so, they die.

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    $\begingroup$ It would be interesting to know how this lifespan is calculated. If someone lives healthily and exercises, eats good food, do they get more lifespan to spend? Will a guy in his twenties die from walking too fast because he's supposed to be hit by a bus tomorrow? $\endgroup$ – Plutian Jul 1 '20 at 17:08
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    $\begingroup$ Plot twist: when they finally die, they have to actually go back and do all of the actions they spent their “life energy” on. Whatever idiot decided to walk around with a car for one minute now has to spend 399 minutes at the end of their life picking up cars. And whoever overuses super-speed is going to be taking a really long hike. $\endgroup$ – Franklin Pezzuti Dyer Jul 1 '20 at 20:50
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    $\begingroup$ Perhaps a more interesting use of this power: can you use it in reverse? So every single time you have to waste time waiting for something (say a youtube video advert, waiting rooms, in transit of public transport most especially plane rides, nice way to avoid/reduce jetlag as well), you slow yourself down and save up that time for later. $\endgroup$ – Demigan Jul 1 '20 at 21:40
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    $\begingroup$ I don't think much would change because if everyone superhuman, the no one is superhuman. $\endgroup$ – DKNguyen Jul 2 '20 at 4:21
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    $\begingroup$ @Aliden Shotput then: as you throw it, you "boost" as much as possible. Doesn't matter if you die partway through, so long as you can accelerate it enough before then that the projectile is moving with sufficient velocity when it hits something. f=ma and v=u+at, so from u=0 and rearranging for a=f/m, we get v=ft/m. Mach 10 is 3430m/s, average shotput throw is around 10m/s, so you only need to handle a multiplier of about 350 for less than a second (6 minutes) to simulate the yield of a small tactical nuclear bomb... $\endgroup$ – Chronocidal Jul 2 '20 at 15:08

10 Answers 10


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You have created the ultimate urban assassin. It is impossible to keep these people out. Even if you build an entire bunker with 50ft walls of electric razor wire, they just have to stand 5 miles away from the bunker, wait until someone opens the door, then run the 5 miles in half a second and they're in.

Note: In your example a person can walk a mile in 20 minutes, or walk it in 1 minute at a cost of 20ish minutes lifespan. Here's the thing: Both cases use up 20 minutes lifespan. The only difference it that without superpowers you have to wait the 20 minutes until you get there. This rule is always true.

In the next half second they run into the centre of the bunker and murderkill the commander and everyone else in the room. At this speed choice of weapon does not matter, since they can stab someone as quickly as they can shoot them.

The main advantage of one weapon compared to another is the ease of concealment.

The far more important questions is How will everything else change in reaction?

Added Later: You could also plant a bomb.

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    $\begingroup$ Assuming, of course, that the door to the bunker can be seen from 5 miles away. But point taken. $\endgroup$ – Aliden Jul 1 '20 at 18:22
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    $\begingroup$ Very useful insight. The lifespan needed to do something ultra-fast is how long it would take to do it at normal speed if everything else was frozen in time. $\endgroup$ – Emilio M Bumachar Jul 1 '20 at 19:32
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    $\begingroup$ What do you do when bunker builders start using sets of two doors, airlock-style, where only one can be open at any point ? You already see that kind of things in some banks and jewelleries. $\endgroup$ – Pierre Cathé Jul 2 '20 at 7:34
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    $\begingroup$ So you see, general, by putting the bunker entrance at the top of this ramp any assassins approaching at 16 km/sec will launch themselves into orbit. $\endgroup$ – mjt Jul 2 '20 at 14:28
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    $\begingroup$ @PierreCathé Or maybe there will be such a high attrition rate that the only people who can stay in power are good people who no one wants to assassinate. That's the dream. $\endgroup$ – Daron Jul 2 '20 at 15:44

Sniper rifle.

That is my choice because I want to conserve all my precious life and I don't like to get blood and guts on my hot weather linen suit, which I also hope to conserve. Maybe I can cash in a few hours of life for super sniping powers for the second or 2 I need them. I probably would have been pretty old for those hours anyway. I hope.

If drones with missiles are available I choose those instead. Also the person who knows how to fly them. I will stand behind him and point excitedly at the screen when I see something he is supposed to shoot at. I might be tempted to use a little extra life to be able to point more emphatically than is usually possible for ordinary people.

  • $\begingroup$ An excellent answer in those cases where you get to choose the battleground and have access to resources beyond the means of normal people. Upvoted. I'm also curious about cases where those extra resources are not available. If you have thoughts on that, feel free to post another answer. $\endgroup$ – Aliden Jul 1 '20 at 17:20
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    $\begingroup$ @Aliden - "Weapons" is pretty broad - I expected you to come back with "I should have specified: this is early medieval Game of Thrones type world and you are fighting in an empty quarry". $\endgroup$ – Willk Jul 1 '20 at 17:53
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    $\begingroup$ @Aliden 'resources beyond the means of normal people' is stretching it in some places. Here in the US I could order any of a number of military grade sniper rifles for maybe 2-3k USD (for perspective, many hunting rifles are less than 1k USD), and easily get acceptable (not AP, but still good enough if I'm only making head shots) ammo without anything but a background check for the gun. Even a good AMR is on the order of maybe 15k USD (though .50 BMG ammo is neither cheap nor readily available like .300 WSSM, or or .338 LM). $\endgroup$ – Austin Hemmelgarn Jul 2 '20 at 17:31
  • $\begingroup$ "I might be tempted to use a little extra life to be able to point more emphatically than is usually possible for ordinary people" Lol :) $\endgroup$ – The Daleks Jul 2 '20 at 19:53
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    $\begingroup$ @Aliden So, step 1 is to use your super-speed to steal a sniper rifle and ammo from a military depot? Getting the drone is probably a mite harder though. $\endgroup$ – Chronocidal Jul 3 '20 at 13:14

Since eveeyone has these powers (I assume) it will refocus people on small-arms combat. Why bring a tank if your opponent can do the act of leaving the hidingplace they are holed up in, sprinting to the tank, placing a big shaped charge on a vulnerable place (say top of engine compartment) and detonate your tank.

People will also refocus on two things: staying undetected and using their powers as little as possible. With the knowledge that the speed upgrades dont take from your lifetime from your perspective people would focus on this power the most to do massively quick surprise attacks. If you are already doing 100km/h (this assumes gravity is multiplied for free to reach these speeds otherwise you would have to jump everywhere) by the time your opponent even notices they might be under attack, you can get close enough to use a pistol or bigger weapon at weakspots like the neck, or spine. Which is why people readying for combat would try to stay unnoticed as much as possible so they can activate first or activate before their opponent finds them. And when engaging in a live area they go in full speed, as activating it after your opponent means you are likely already dead.

This also creates a battle of time stealing. They can force enemies to react to something that might be an attack, or might not be. Each time the enemy is forced to activate just in case and check if they are attacked or not.

In a more civilian setting: bring a pistol. Its easy to hide, and each time you are about to shoot someone you speed up for the duration of the aim and shot, which takes fractions of a second and gives you the time to check if more shots are required before dropping your speed again. This is especially true because not everyone is a marksman or able to get their hands on a sniper, handguns are easier to learn, aquire and bring with you.

  • $\begingroup$ Everyone does not have these powers, but this nicely covers the case where multiple people with these powers are in conflict. I especially like your point about handguns in a civilian setting. $\endgroup$ – Aliden Jul 2 '20 at 12:34
  • $\begingroup$ Regarding sniper rifle vs pistol : IRL, non-sniper rifles are MUCH easier to learn/use efficiently than handguns (actually, sniper rifles are easier too ; it’s just the sniping part (accounting for range, altitude difference, temperature, bullet flight time, etc.) that’s much harder). Illustration with the M1 carbine vs the Colt M1911 it was set up to replace : forgottenweapons.com/1911-vs-m1-carbine-in-a-practical-match Also, rifles are easier to acquire than pistols in many parts of the world. $\endgroup$ – breversa Jul 2 '20 at 14:23

I would assume this power would be used very sparingly, as a life is not something someone throws away lightly. Therefore I would assume regular weapons to be used, but with the added bonus that people would use this power in times of need. Short burts of strength to make sure an axe blow hits true and hard, an extra powerful leap to the side to dodge said blow. Rather than the weaponry, I'd sooner see battle tactics evolve to make the most use of this power in the shortest amount of time. Fighting would be more like chess, or advanced boxing if you will. Focused on the best moment to use your power, how much of it, and what your enemy might do. The speed of battles would evolve, as your main concern would be to use your power to take out your enemy before they have a chance to use theirs.

There would be of course the odd ogre swinging around a club much too heavy for them normally, but they would soon figure out that is a clumsy tactic and very dangerous to themselves. To develop a weapon that can only be used by spending your life means you can only train with it by doing so, after extensive training a master might die in his thirties before ever seeing a battle. I suppose you would see an increase in heavier weapons as they can be used swiftly and with sudden and heavy blows using this power, but that is about it.

On the other end you might also see more suicide troopers. Soldiers knowing they will not survive the fight, and going out in a blaze of glory on the battlefield. Similar to berserkers, they will go on short massive rampages trying to do as much damage as possible in a short amount of time. They might rip entire trees out of the ground and swing them like matchsticks, or throw boulders across battlefield like pebbles. But as I mentioned before, it is unlikely someone so reckless would take the time to extensively train for such a moment.

I should note that I especially aimed this answer at midieval weaponry, and not modern. Modern weaponry will overpower even superpowered humans. On the battlefield, whether you run at 10 mph or 20, a bullet will kill you all the same. You might be harder to hit, but a bullet will always be faster. Even when you swing around a tree, a grenade at your feet, or a well placed mine will blow you up just the same. Similar to how a crossbowman who trained for a week could take out a knight who trained for a lifetime, modern weaponry would render this power mostly obsolete.

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    $\begingroup$ Ah, but these people can make themselves bulletproof. Divide the energy of a bullet by enough copies and it's like getting hit by a gently thrown rock $\endgroup$ – Aliden Jul 1 '20 at 18:17
  • $\begingroup$ @Aliden so is this fighting with non superpower/normal people or against each other? also what their weakness then? if they can withstand bullet? sharp object? suffocation? poison? or they can only die after their lifespan is fully spend up? $\endgroup$ – Li Jun Jul 1 '20 at 18:22
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    $\begingroup$ @Aliden you'd have to see it coming from a mile away though. Bullets are still pretty instantaneous, before you realise you've been hit, the bullet is already halfway through the wall behind you. Unless the power can increase your thinking as well, in which case the whole dynamic of this question changes. $\endgroup$ – Plutian Jul 1 '20 at 18:29
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    $\begingroup$ @Aliden Dodging or tanking bullets is probably a bad idea. But it's also unnecessary when you can zip zap zoop into the gunner's faces' before they see you. $\endgroup$ – Daron Jul 1 '20 at 20:25
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    $\begingroup$ @Blueriver Ahhh, but the life expectancy was shorter in medieval times so what life pool are you drawing from? When you could have died? Or when you would have died? Because if you could live to 100, but something will probably kill you before you're 50, could consume a huge portion of your lifespan and never even know because no one ever lives that long. $\endgroup$ – DKNguyen Jul 2 '20 at 4:24

I'm going to open with the quote from Daron's answer:

Note: In your example a person can walk a mile in 20 minutes, or walk it in 1 minute at a cost of 20ish minutes lifespan. Here's the thing: Both cases use up 20 minutes lifespan. The only difference it that without superpowers you have to wait the 20 minutes until you get there. This rule is always true.

because I think it's way underappreciated what kind of effect this has.

Let's say I want to go to the store, and it's a 20-minute walk. There are a few options:

  1. Drive 5 minutes
  2. Walk 20 minutes
  3. Take 1 minute real-time at 20x speed (costs 20 minutes lifespan)
  4. Take 1 nanosecond real-time at 1,200,000,000,000x speed (costs 20 minutes lifespan).

This holds true for every single action a human would want to perform, as long as it's under their own power.

Without an additional cost or restriction on this power, your world actually consists of two completely disjoint timescales:

  1. The part where non-human-powered actions like driving a car, exploding bombs, or equivalent take place under the laws of physics.
  2. The part where human-powered actions occur instantaneously; everything teleports.

It's a world of blood magic Flash-es where the fundamental question is "do I want to buy the difference between what it takes to perform action X as a human vs using non-human assistance in lifespan, for the price of having it happen infinitely slower?"

Combat in this world is undefined mathematically. Suppose you're in a fight to the death, then you'd be willing to expend the rest of your remaining lifespan's worth of physical effects now. So does your opponent. The result depends completely on how competing uses of the power interact.

The actual form of physical effect is only relevant for efficiency considerations; anything that causes death/undesirable consequences under human power (and/or whatever human-powered escaping of it) is fine. Note that this specifically does not include any sort of firearms!

Supposing it's relatively balanced, then every single fight becomes an all-pay auction in which you bid however much lifespan you want, and the higher bidder wins - both lose the lifespan bid by the loser (read: war).

Presumably a social structure that really strongly discourages this type of fighting (which has zero physical countermeasure) would emerge. Or maybe you get a totalitarian state which breeds expendable, unknowing humans as suicide bomb-enforcers, and economic power is reproductive output.

Note that human-impassable types of defences (steel doors) also fundamentally block the defender. It just segments space into non-interacting regions where only physics works. If you have a steel door, either I teleport enough shaped charges (and you can't do anything about it from the other side), or you need human defenders, and we're back to Flash-on-Flash lifeduels.

This reminds me of a scene in The Library at Mount Char where

Some characters, having speed-up-own-time superpowers, are trying to outrun an explosion. While doing so they find out that the air itself can't get out of the way fast enough, so they're at risk of escaping the bomb but burning to death anyway from friction.



How are these powers activated? wouldn't children be the most powerful then? If you could induce a child to activate a power and do something for your benefit, an evil overlord would simply focus on that tactic, rather than using own powers.

Could you use it persuade people ? If I focus on improving my persuasion skill and then use the required time to convince somebody to use the power on my behalf? Isn't that more fruitful? So I would bet the most powerful weapon would be other people, as they have all their lifespans available to them.

You could get people who are skilled at something and then make them use their abilities, as essentially any skill improvement leads to reducing your time multiplier required to use it to a super human level.

Since this ability is a multiplier of your innate abilities, it makes sense to improve innate abilities and get better powered abilities from them. An individual is weak, but a group working towards a cause would only be stopped by a similarly committed group.

Human psychology is bad with future costs, so it would also result in people overestimating the costs, and suddenly die with no cause. I love the concept though. See runelords for a similar idea.


Thrown weapons.

Let's consider the ultimate thrown weapon: Project Thor, a.k.a. "The Rod From God", or "hypervelocity rod bundles". Basically, if you throw something fast enough, then it hits with the equivalent of a small nuclear warhead. How fast? Well, the US Air Force estimated that Mach 10 would be a good number - albeit, for projectiles massing about 1000kg. This would roughly equivalent to an M29 Davy Crockett.

This is, of course, completely overkill - so, let's scale it down (slightly). Instead of a 1000kg tungsten rod, let's use a 7.26kg Shot Put. For the sake of simplicity, let's round it up to 10kg instead, too.

Now, Kinetic Energy obeys the following calculation:


This means that we will "only" be delivering the equivalent of 0.1 tons of TNT to the target. But, how much will we need to "boost" by to manage this?

Well, $F=ma$, and $v=u+at$. We will assume that we start from rest ($u=0$), and rearrange to get Acceleration in terms of Force and Mass ($a=\frac{F}{m}$), and plug it together:


(You can, if you want, take this a step further, to get $E_k=\frac{F^2t^2}{2m}$)

Mach 10 is 3430ms-1, and the average Shot Put speed for a professional athlete is around 10ms-1. This means, we only need a multiplier of 343, during the about-a-second it takes to make the throw. If we call this 360 for 1 second, that's only burning about 6 minutes of life.

So, what if we want the full Nuke experience?

Well, Kinetic Energy scales with the Square of Velocity. To "correct" for the factor of 100 that we have dropped in Mass, we need to increase velocity by √100, or 10 - and we can deliver the equivalent of the world's smallest nuke for an hour of life.

Now, if we're delivering nukes at point-blank range, we might not survive anyway. So, how far can we push it? Little Boy, the warhead dropped on Hiroshima, had a yield of 15kT - that's 1500 times more than the Davey Crocket. So, scale it up by √1500, and that's just short of 39 hours.

What if we went all the way to the top? Russia's Tsar Bomba is the most powerful nuclear warhead ever detonated. It had a yield of 50,000kT - so about 5,000,000 times our 1-hour blast. Plug the numbers in: √5000000 = 2236 hours, a.k.a. 93 days, or about 3 months of life.

How about every nuke ever detonated? That's about 550,000kT of material, and √55,000,000 = 7416 hours, or 309 days.

That's right. For the low-low price of 1 year (and the rest of your life), you could - briefly - become the Ultimate Nuclear Power.

Now, let's scale it right back. A throwing dart, for playing darts, weighs about 20 grams. That's 500 times less than our Shot Put, so it delivers 500 times less power. This means it delivers an energy on impact roughly equivalent to its own mass in TNT.

Now, some people might complain about the sonic boom. To which, all I can really say is: a Busemann biplane could make for an interesting projectile shape...

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    $\begingroup$ An hour to throw the mini nuke, and a day to run away :) $\endgroup$ – Mirror318 Jul 2 '20 at 21:20

AI and automated weapon systems

Let's face it: soldiers' lives are a dime a dozen, at the very least when you're at war. Sacrifice ten people and an aircraft to take out the enemy leadership? Someone will take that deal. Even worse, the degree by which a 20-something attacker could speed up for a suicide attack (1000x seems feasible if we assume that physics don't allow for unlimited speedup), at the attacking side's whim, makes for such a force multiplier that defense, even for another group of super-soldiers, becomes a hopeless endeavour.

If you're human, that is. AI controlled systems can realistically match the reaction time of a sped up person, and unlike your super soldiers, an automated turret does not keel over from exhaustion five minutes into the battle.

In addition, while dodging or deflecting one bullet is probably doable for a skilled user of your ability, it still has a cost. Being pelted from different angles will quickly deplete your life force.


Where automated weapon and security systems aren't cost effective, you'll have to rely on subterfuge. It's likely that the political and cultural elite of your world are effectively anonymous - with elaborate, but thoroughly artificial public personas that bear no resemblance to their biological form. In a nutshell, Death Note if the Shinigami were all bored out of their minds and decided to share their powers more... liberally.

Your supers should take all this up to 11

As stated above, the superpower makes for one hell of a force multiplier, not just in combat. I would expect people with this ability - at least those not sacrificed in five-minute wars - to excel at whetever career they choose. Which makes them both a priceless resource and a juicy target.

The wealthy and famous among them will have the means to afford the best protection that the market can provide. Those less fortunate will have a sponsor or employer who does the same for them. No nation or company would want to risk losing these people, and considering that even a successful defense would cost them dearly, using the power in self defense should be a last resort.

Instead, expect them to have airtight security, secret identities and a network of support personnel.

Super soldiers need super weapons

Outside of covert operations (that might well be the norm), even those that (were) volunteered for combat duty will not have to charge in with knives or cheap guns. Yes, they'd do a lot of damage, but so do cruise missiles and artillery, except at greater ranges and, depending on how many people have this ability, arguably a lower cost.

It is far more cost effective to give them the tools to fight without constantly depleting their life force. They'll have vehicles for protection and drones and other automated weapons to extend their influence over as much of the battlefield as possible, taking direct control only in key moments and areas of the conflict. They'll still have to use their powers in extremely intense bursts (anything less makes you a huge target on this battlefield), but at its core the ability is a force multiplier and should be used on as much of your force as you can.

  • $\begingroup$ This doesn't answer the question as asked. The question asks what weapons the people with the superpowers would use, not what weapons would be used against them. Unless you're asserting that they would be the ones using the AI systems? $\endgroup$ – Aliden Jul 3 '20 at 2:11
  • $\begingroup$ @Aliden Everyone would (have to). I'll expand on that. $\endgroup$ – Ruther Rendommeleigh Jul 3 '20 at 7:09

They would use the same weapons as everyone else, but boosted by their ability to aim and fire and move from cover more rapidly.


Forget a tactical nuclear warhead: one decade of their life is enough to let the average person exceed the speed of light with a punch.

Baseline: 1 m/s. Given that the fastest professional boxer clocks in at a bit over 11 m/s this seems fairly reasonable, and it makes the math come out nicely; also, I did it just now, sitting down, without any particular effort.

60 seconds/minute * 60 minutes/hour * 24 hours/day * 365.25 days/year * 10 years = 315,576,000 (3.16E8) … while c≈3.00E8 m/s

For a fun breakdown of the effects, I refer you to the very first XKCD "What-If?".

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    $\begingroup$ Note that the XKCD is for something moving 0.9*c; once you reach it (much less go past it), all bets are off. $\endgroup$ – Joel Aelwyn Jul 6 '20 at 20:01

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