# What kind of spells would magicians cast in combat if the fuel to magic is very expensive

In the story I’m working on, there is a strict ruleset on how magic works, one of the main points being it needs a “fuel” to work, and that “fuel” is VERY expensive. That being, most magicians use their skills while saving the most fuel possible. Against ordinary foes, without any magical abilities, they usually use it to create a burst of wind that destabilizes the opponent and simply finish them off with a dagger to the heart, much like Andrzej Sapwoski’s witchers use their “Aard” Sign (more of a distraction than a weapon). But, against other magicians, things are a little different. There are big coliseum styled magical fights, those being more entertainment oriented, so they’re usually big flashy combats with fireballs and lightning flying everywhere. But that’s when I got cornered. In actual magical military combat, saving magic fuel would be a primary concern as well, and magicians would probably favor extremely lethal and economic spells over big fiery blasts. Please consider the following:

• ”Magic” is the ability to control forces of nature (wind, water, flames, lightning) and inanimate objects.

• One ****insert fuel unit here**** is enough to cast 100 wind blasts powerful enough to stun or knock out an adult male, or 10 fireballs the size of an orange;

• Magic cannot create, only manipulate what already exists. You cannot shoot fire from your hands, you have to actually set something ablaze and control the flames;

• Magic does not affect living beings (people, animals, plants), in the sense of altering their living bodies. There is no polymorph, mind control or magical enhancements to strength or speed. You can’t just vaporize your enemies. That extends to the natural elements inside the human body (water, electricity, iron...) There are, however, ways to affect armor and clothing.

• The range is how far the magician can see. Sight augmentation apparel can extend the range.

• They can control whatever they can see. There are no microscopes yet, so they cannot control individual atoms or molecules.

• A single magician power is limited by his knowledge, amount of fuel, and psychological endurance. Casting large spells have a heavy toll in one's mind, and trying to cast a spell too big to a single person would effectively kill the mage. With that in mind, big spells are usually cast by groups of mages holding hands, so they can share the stress and fuel expenditure of such grandiose acts.

• There are no permanent spells or "curses". A spell exists as long as someone is casting it. If the caster is incapacitated or killed while casting, the control over that specific element is lost and it will simply follow physics from that moment on.

Based on those rules, what probably would magicians cast in a mage fight? What force of nature is easiest to control and deadliest? Would they just walk around with a pocket full of knives and hurl them with lethal precision at their magician foes? Would they ignore magic and sword fight each other until there is an opening for a wind blast? Please note that I’m not asking about the magic system, which force of nature ACTUALLY is the strongest or that kind of thing, I’m asking about military combat tactics that for some reason include magic.

UPDATE: I was blown away by the amount and quality of the answers here. Almost every single one has inspired me in some way, but as we now have a two days old question I must choose one to be the solution.

Since warfare tactics are pretty much covered, I'll choose the solution based on the duel aspect of the answer (or not necessarily duel, small fights between mages may fit as well). I won't choose one of the existing ones about duels mostly because they miss some points:

• Mages are human. Could you think about bullet-proofing your clothes, blow away projectiles with wind and turn the ground below your opponent into mud at the same time? They can't, either.
• You probably wouldn't want to save fuel while fighting for your life, only enough to not be unarmed.
• No, you can't mess with your opponent internals. No pressure, air pockets in the brain or that kind of thing. The physical space that the body of a person occupies is completely immune to any kind of direct manipulation by magic.
• Obviously, a fight between an expert mage against a non-mage or a novice mage will be a slaughter. Think even power levels.
• The world is big and there are many countries that practice magic. There are many styles of magic and many functions to a mage. Maybe illusionists have a common prejudice against elementalists because "they make too much of a mess".

Thank you!

• Comments are not for extended discussion; this conversation has been moved to chat. Jan 19 '17 at 15:48
• How difficult is to become a mage? Can you train conscripts into basic battle wizards in 6 months, or do you require years of study? Jan 19 '17 at 19:19
• I'm reminded of the series where magic was in the form of song but attempting to affect anything living took a heavy toll on your lifeforce and could easily kill you; but inanimate objects and substances were fair game. Jan 19 '17 at 21:04
• Are magicians necessarily male? The question and some answers seem to assume this. Jan 19 '17 at 23:48
• Could a magician create a 60°c of the size of a bullet in the head of an enemy? What is the accuracy of this heat point? How many concentration and mana consumption of this ? Can i just kill some one at less than 100 meter in less that a 1sec just by picturing that they are dead ? If heat is too hard to handle may I torn their brain in 2 it s really basial magic... Jan 20 '17 at 8:51

Snipers

Given the rule that magicians can control what they can see the most effective place for a mage would appear to be as a magical sniper, special forces or artillery. It's also probable the most efficient option in terms of energy.

You probably don't want your highly valuable "fuel" falling into enemy hands so it's best to keep mages behind your lines.

You don't want to waste fuel on flashy flames and lights unless it's for the sake of shock and awe.

An exception would be arson. A few small fireballs or levitated balls of flaming oil in your enemies supply caches can do wonders or magical artillery launching flaming oil.

In a battle between 2 armies, both with mage support it becomes a game of seeing without being seen. If a mage sees you he has pretty good odds that he can throw a small poisoned dagger and plant it in you at high speed.

Taking out key figures would be a priority, the war is practically over if someone puts a nail through the neck of the enemy general.

If a mage sees another mage without being seen you get a similar outcome.

Mage spies and special forces would also be powerful. If the king is foolish enough to strut around in front of crowds without protection then he's liable to get a dagger through the eye.

Mages might even routinely hide their identity so that they can hide in a crowd. Battles become more a matter of figuring out who the other mage is first in a spy vs spy urban environment.

What can non mages do to defend themselves?

Smoke, fog, darkness. All would be allies to those without magic. If a mage can't see you he can't kill you easily. If you can cover the battlefield in enough smoke your men can get in close where they have the advantage of numbers.

Mages meanwhile might try to clear smoke with bursts of wind and light up the dark with bright magical flares and follow up with long range projectiles.

• Nice answer! Any thoughts on duels to death between mages? Jan 18 '17 at 13:08
• @resch In case of magic snipers, you should watch the movie "Enemy at the gates" about a Russian and a German sniper in WWII Jan 18 '17 at 13:09
• @resch lots of cloak and dagger. Secrecy would be a great weapon. Mages might even routinely hide their identity so that they can hide in a crowd. Like a sniper battle where it's harder to miss if they're both in uniform on a battlefield. More a matter of figuring out who the other mage is in a spy vs spy urban environment. Jan 18 '17 at 13:19
• You may find that many mages are proficient in armed or unarmed combat to a greater or lesser degree.
– Paul
Jan 18 '17 at 13:40
• @SnoringFrog Poisoning someone like that is much harder than it sounds. Humans are incredibly resistant to poisoning - too little poision, and the target just gets ill for a while. Too much, and he'll expel the poison (e.g. vomit). You need a very precise dose, which must be tailor-fit to the individual you're tring to poison. And even if you did have a workable poison that magically worked like this (the fearsome "Hollywood poison"!), the important people would just use a shroud of some kind to prevent contact with the poision. Jan 19 '17 at 12:44

### Support and Engineering

With the cost of fuel so high, a primary concern is having that fuel fall into enemy hands. So you're probably not gonna want trucks of the stuff on the front lines. We see this in real life with real fuel and assets. They are stored "away" from the battle and moved in when needed, at FOBs (Forward Operating Base).

Also, you probably don't want you mages getting captured and turned. Again we have real life examples of this with code breakers, code talkers, and high end equipment (among others). For example, a jet is to be destroyed if left behind enemy lines.

So the best place to use a mage is to give your normal army an advantage. It doesn't take much. History is filled with examples of armies winning amazing victories for no more reason then they have the high ground. To that end, how about have them be engineers instead of combatants. They can use their abilities to do simple things like making a land bridge, destroying current bridges, enhancing natural cover, mildly affecting weather.

Take a look at the "Battle of The Bulge" during WWII. At its core, the 101st defended Bastongne with very little support, while the German army's plans hinged on the ability of their army to rush across the Meuse River in just a few days. The Germans would have had a much easier time if somehow a "mage" was able to clear the woods with fire. Also, the 101st was able to hold the area, in part because they had superior air power. The Germans had to wait until the weather grounded the US air forces. Field Marshal Von Rundstedt is on record saying "Weather was a weapon the German army used with success". If the weather could have been kept clear, the 101st may have had an easier time. If the Germans could have helped the bad weather along, they may have won.

Finally, the Germans initial plans called for a bunch of fuel for their tanks that never reached the area. Bad weather, poor roads, and other logistics problems kept the fuel from getting there, at the same time the US forces burned gas to keep it from falling into their hands. Here again a single mage, with little "effort" could make a huge difference. An allied mage, screwing with the supply lines by washing out bridges, thawing ice along the planned route, setting fires in fuel depots may have ended the battle sooner. On the other side, mages securing the normal fuel supply could have caused the destruction of the 101st.

Mages in support and engineering roles could have a huge impact with little "fuel usage". It doesn't take much to swing a battle in your side's favor. If fuel is that rare and expensive, then you don't put it in range of the bad guys. You keep it safe far away.

### Propaganda

Part of support in my mind, but looking at WWII again, the US (especially west coast and New York) had a very high level of fear. Nukes were a new thing of course, so that wasn't really a "real" concern, but Japan was making good strides in Naval warfare, and NY was just a natural target. In both cases things like Subs (German subs especially) caused fear. Like they would pop up in the middle of Manhattan harbor and start launching missiles. On the west coast, Perl Harbor had "just" been destroyed. What's to stop Japan from doing the same with L.A.? Totally "civilian" worries as the military had it under control. But without the civilian support, especially the US military crumbles.

Remember the US was dangerous in WWII because, largely, because it was not in the war. It was an untapped pool of manpower and raw materials. With Pearl Harbor, the civilian population now had a reason. And unlike Britain and others that were holding on, and fighting for every inch, the US was able to enter the war, with largely untapped resources. For example, people in London were being bombed nightly. There was rationing of food and materials because they had no choice. In contrast, the US civilian population now had a reason to "ration", but unlike many of the allies, the US could devote the extra materials to the war. There are stories of women giving up metal hairpins, and wool metal scrubbing pads to make munitions etc. All that raw material and manpower entering a war where everyone else had already expanded large parts of their reserves made a huge difference.

A mage or two heightening the fear factor along the coastal areas, or a mage or two making the civilian population feel more secure in those areas could drastically have changed the US presence in the war.

So in summary, mages would play largely support roles. Places where a little magic fuel can make a HUGE difference. Take a look at the Army core of engineers. A block of C4 to blow a bridge to stop the enemy advance has a larger effect then 1,000s of blocks of C4 to stop the tanks individually after they cross the bridge. Because of that mage fights would largely be a non-thing. If two mages see each other they just wave and go on about their business. The normal soldiers, that would be defending the mage, would do all the fighting.

In fact, mages may model more after real world non-combatants then you think. With provisions in the Geneva conventions and all. An agreement between mage "guilds" that no mage may participate in direct combat during wartime. And that the protection similar to that of non-combatants as POWs today would likely evolve. Especially with fuel being so rare.

• Nice answer! Two points I must clarify: warfare evolved alongside magic, since the times tactics weren't such a great thing. Mage fights are deeply rooted in this people culture, so they are common after all, because they basically replace weapons engineering in the story. The second one is that the "fuel" is expensive, not rare, because of monopoly. Only one city-state has the means to extract it and they heavily militarized the extraction fields, so they sell it to others at whatever price they want. But overall great answer! Jan 18 '17 at 17:54
• I think this stands. If 1 bullet is $5 but 1 magic rock bullet is$10 then you arm your people with bullets. Jan 18 '17 at 20:33
• The SE parser didn't like that one, but I hope you get the point. Jan 18 '17 at 20:34
• @coteyr -- The MathJax parser treats anything (within a single paragraph) between two \$ signs as a variable name. An entire comment is treated as a single paragraph, even if its markup code contains line breaks. Jan 18 '17 at 22:20
• +1 for examples of actual battles and how mages would've shifted the results of them Jan 19 '17 at 14:43

# Counterspell

Spells are expensive and take concentration. A wizard that's good at multitasking can repeatedly wreck the enemy's concentration on a more powerful spell with simple low-cost tricks like blowing air into their eyes, and then run up to them and shank them in the neck.

• Mercedes Lackey had a fire mage who had great aim and range, and very limited power. He would set the hem of an enemy mage's robe on fire at well-timed moments. (Don't remember which book, probably one of the Valdemar precursor series.)
– arp
Apr 18 '18 at 11:39

You have two conflicting uses for the fuel here. The first is for showy gladiatorial fights and the second is military power. I don't see them as totally mutually exclusive, but more like branches from a common art.

In some of the very old martial arts, there is a calcification with the old traditional forms and movements that were based on techniques that were effective once upon a time. Tae Kwon Do seems to have been developed for dealing with enemies on horseback when you look at the high, powerful kicks. Those kicks are devastating to an opponent when they hit, but against another person on foot, they are relatively easy to dodge. This is the path I see the gladiatorial magic to follow. Flashy fireballs and ice and windstorms might have been effective in a military sense once upon a time but as tactics evolve they would become less and less useful.

The modern military mage is going to understand that power brought to a point is far more effective than any amount of flashy fireballs. Military actions are won more by efficient application of resources. This means things like mages augmenting the flight of arrows, acting as snipers, and of course, spying. It doesn't take a huge amount of energy, properly focused, to break a generals neck or blow a blood vessel. Magic could be used as triggers for traps.Even magic being utilized to catalyze a poison in the enemies water supply. Subtle is better than flashy, lest an opposing mage try to break your neck for your troubles. These kind of subtle techniques would be more efficient in terms of fuel. No flash and sizzle, but no less lethal for it.

• So far as I know the Tae Kwon Do horseback thing is an urban myth with little or no supporting evidence. Do you have any evidence to back it up? Jan 19 '17 at 7:47
• Frankly my source was a sparring partner from many, many years ago. I do know from first hand experience that the big, flashy kicks are absolutely devastating if they land, but aren't terribly difficult to counter with good footwork. They do leave the practitioner exposed, to small, precise movements. The horseback thing was plausible to me because of the origins of many wooden weapons like Tonfa, Kama, and other things. Jan 19 '17 at 14:42
• Yeah, the idea is certainly circulating among the people who practice the art but there's very little actual evidence to support it so far as I know. (Although I make no claim to be an expert). Jan 19 '17 at 15:47
• Part of the problem is that most of the information is anecdotal and passed along in ways that would be called "oral history" by historians. The stories sure are fun though. I like the idea the board breaking started because the Japanese wore laquered wood armor and that a lot of the wooden weapons were created because Steel weapons were only allowed to the nobility. It's fun! Jan 19 '17 at 16:33

### Siege Weapon

”Magic” is the ability to control forces of nature (wind, water, flames, lightning) and inanimate objects.

Since the mage can manipulate inanimate objects that would include walls surrounding castles, fortifications, and cities. A mage or small group of them could pull down part of a wall and create a ramp thus breaching the defenses. This would dramatically speed up sieges. The city being sieged would likely have their own mages working to keeping the walls up, but because of the siege they likely have limited sources of fuel for their magic, and would eventually give out to the side conducting the siege.

### Magic Powered Rifles and Other Military Hardware

This goes hand in hand with the idea of using mages as snipers, but can be applied in a more general sense. A mage can use their magic with existing weaponry to enhance its effects and make it more deadly in combat. By leveraging existing military hardware this would reduce the burden on the fuel for the magic and help it last longer.

Alderamin on the Sky has an example of this with their air rifle. Each rifleman had a wind spirit for a partner that acted as a power source for their rifles. The air rifle shot a projectile, but instead of using combustion to propel it the wind spirits built up air pressure in a chamber in the rifle which rifleman released to fire the bullet. They also had air powered mortars and artillery which worked similarly but on a larger scale.

Another way to combine magic with existing hardware is with catapults. If mages can create a more powerful version of a flaming jar containing pitch/tar/resin they could use the catapult to throw it rather than having to spend mana to throw it.

### Enhance or Create Hazards

A group of mages could spend a sizable amount of mana to summon a lightning strike on their foes, but what if it is already raining and there is already some rumbling in the clouds? Instead of creating a lightning bolt from scratch take what nature gives you and spend a little bit of mana to direct it (and possibly scatter it) so that it lands in the middle of the enemies forces.

Rain itself could be turned into a nasty weapon. Rain is already falling at terminal velocity, so freeze it into small spikes and speed it up some more, thus creating some nasty hail. This would not be deadly, but it would hamper the enemy.

### Logistics

War is also not only fought on the front lines. There are other aspects to war that mages can help out with that can turn the tide of battle. Mages can use their magic to help create bridges over difficult to cross rivers and also destroy enemy controlled bridges. Small things like this can benefit your supply and troop movements and/or negatively impact enemy logistics.

If the enemy has a key road they use to move their supplies (like a mountain pass), sneak a mage back there and have them remodel the road with a huge mound of rocks (triggering a rock slide) or create a giant hole. This would create delays in the enemy troop movements that can decide battles before they even start.

• Good ideas about sieges, +1. Jan 19 '17 at 0:29
• Do you have any idea how deadly hail can be? Hail the size of baseballs can be lethal to animals that can't find shelter, and if the hail is aerodynamic due to being pointy, it'll fall faster and deal more damage. Trust me, it's not just going to hamper the enemy. Jan 13 '21 at 22:20

Fireballs might very well be "cheap" in your fuel, depending on how exactly your magical system works. The main idea is that all of the energy doesn't necessarily come from the fuel - it's a reaction of the fuel with something else.

A piece of coal burning consumes carbon from the fuel, true. But to do this, it reacts the carbon with ambient oxygen - if you shut off the oxygen access, the fire dies. For perfect burning, you convert carbon and oxygen to carbon dioxide - the mass ratio is 6 fuel to 16 oxidizer (for free from the environment). This means that for a fire of this kind, you only need to supply 25% of the required matter.

A high explosive works differently - pretty much by definition, it cannot rely on getting the oxidizer from its environment, so it needs to be internal. So you need to supply all the matter. Obviously, this is a gross over-simplification, but we're looking for patterns here, not precision (after all, your magic might work somewhat differently from our physics).

So the difference between a "flashy" fireball and a high explosive might be a fourfold increase in fuel costs - you need to affect a lot more mass. And yet, against a medieval army, the firewall will likely be far more effective - you want spread; there's no heavy structures you need to penetrate with a concentrated energy release. Not to mention that you don't need to develop any specialised explosives - a piece of coal or charcoal would work wonders, just throw it at the enemy, crush it and provide the initial energy impulse, and you get a beautiful (and relatively cheap) explosion. Anything that readily oxidizes will work well. Of course, concussive explosions aren't great for killing directly, but they will disrupt formations and morale quite handily. And against wooden ships, your magicians are going to do wonders :)

For raw energy efficiency, it's hard to get anything better than telekinesis - but you already have that in archers and catapults and similar. The magician doesn't give you any measurable benefit, and given the cost of "mage fuel", it will likely be a net loss. So you need to do something efficient that isn't done better by a bunch of guys with bows.

Fire actually works very well. It's not so obvious today with modern firestarters and petrochemicals, but the use of fire in warfare was almost impossible in medieval times (the earlier "Greek fire" probably was petrochemical, and largely forgotten - though undeniably effective). Forget volleys of fire arrows instantly setting the village on fire - that's just Hollywood. On the other hand, your magician could do something like that easily - he only needs a tiny burst of concentrated energy to start huge fires, and a thin spread of fire over an enemy formation will likely be quite devastating, especially for morale (which was always extremely important in warfare).

This is especially handy if your magicians can prevent the enemy magicians from doing the same - even if you don't use magic offensively, you need your own mages for defense. And setting the enemy commander's clothes on fire from afar would likely be very easy while also being quite effective. In the long run, this will of course force important units to avoid flammable clothing, but this is actually a massive detriment to their combat performance, so it's still a win.

But that's still fights where the magician is just a part of an army. How does this apply to a duel? Well... not well. Just stab that guy, seriously. Magic isn't going to make it any easier, other than providing a distraction - and since you're fighting another magic user, that's likely as much a problem for him as for you. You'll battle a bit, prepare an opening, blast a bit of dirt in his eyes and just stab him. Or conjure a gush of wind, and stab him. Or conjure a bright light, and stab him. Given your constraints, there's really no way for a magician to just kill the enemy outright, or even substantially inconvenience him. You want to do a tiny, cheap action, and finish with a dagger/sword/whatever. At longer range, you'd just toss stones at each other, probably while increasing their power and precision with your telekinesis. But not really more than a typical slinger would - "muscle fuel" is much cheaper than "magic fuel". Indeed, dagger+buckler and sling might be the perfect armament for a magician in your world.

Of course, if you're obviously well over your head, you might very well choose to use a powerful spell regardless of the cost. But that's probably not a typical scenario - presumably, most fights would be between rather evenly matched opponents; and quite possibly, not to the death either. Especially if any mage can deal a killing blow in desperation, expending all his strength and fuel reserves.

# Cost effective ones

Individual targets are assigned a value. Officers by rank most likely, enemy mages would also high be high value. Officers would be wearing the same uniforms as the men, a change that happened slightly behind the invention of accurate sniping, so spotting them is going to be hard. Senior officers might not even be on the field, relying on relayed communication for commands and intelligence.

Other high value targets of opportunity

• The drummer - a key to battlefield communication
• The bugler - also a key communicator in a battle
• Messengers - Can you see where I'm going with this?

Fuel has a value by availability and projected duration of combat. If you have a lot of fuel and a small number of enemies, it could be worth just wiping them out. Though it may just be a feint to get you to burn fuel casually ahead of the main attack.

Defence spells are also very high value. One of the biggest here will be to bring down a fog, localised (or whole battlefield if it's not working out) over something that needs to be protected from mages. Maintaining a continuous fog over the command tents so officers can come and go safely for example. Can't be seen, can't be directly targeted. You can also take that the other way and stick a fog over their mages so they can't see anything. A smoke screen would do if they can't handle fog, but it's just wind and water.

I'd seriously consider dedicating my mages to sniping and fogging enemy mages and fogging the top of my command chain. With only one or two, depending on numbers, sniping their commanders and messengers. Find the paper for their rocks, the scissors for their paper.

As for the battlefield use, you could take a look at the game Dominions 4. It's a strategy game where proper use of magic is vital to win the game, and there's so much more than the good ol' fireball.
A thing that does not cover however is mage saboteurs targeting stuff like supply depots, which is a pretty good use.

But you seem to be more interested in mage duels. With your constraints, it starts like a gun duel and then as an arme blanche duel.
Let's assume a chance encounter of two mages, there is no ambush and no feasible way of disengage or retreat.

First round: Shields up! (or dive to cover)

In a duel of any kind, the objective is not killing the other, it's surviving. A double kill is as bad as an outcome as just getting killed, so the sensible first action is protecting oneself. That means getting behind cover or raising a small tornado around to deflect accelerated projectiles and counter gusts.

Second plus rounds: Getting around the defences

With your constraints, unless the environment is a building on fire, or in sea/lake/river/very heavy storm, there isn't enough material for fire and water magic to be useful. So it's air and earth time.
From there, depends on the level of the mages and amount of fuel in their bags.
It would go from a nail and stone shootout (from any angle!) to dropping walls, floor breaking and finally lightning bolts and raising stone pikes under the enemy with impaling intentions. With plenty of countergusting, running and wrangling control of the environment (specially with earth magic).

And well... A dramatic dagger melee once there is too much dust raised to see is also an option.

Maybe they could throw a bunch of caltrops in the air and try to control them with powerful wind.

Fire could be used to ignite some sort of arrow and again use you wind so that they find their target.

Normally they will probably try to keep their distance and prefer swift attacks. The faster the better. If they can concentrate the air they could try to "stab" the enemy with a powerful concentrated gust of air to the enemies heart.

Other than that I cannot help but think about the series Avatar where they control the elements.

• With the limitations I proposed one single last airbender styled fight would consume all the fuel the mage can carry. For entertainment it would be awesome as I pointed, but for actual combat it's just too wasteful. Jan 18 '17 at 12:50
• Piling mixed caltrops and rocks into a trebuchet would be a better idea.
– Paul
Jan 18 '17 at 13:41
• I keep thinking about the old saw"Use the right tool for the job" and Magic, as proposed, is just another tool. Think of a kitchen, you can break out the potato rotator, fiddle with it, drop bits and finally end up with a peeled potato, or you can grab the 97 cent potato peeler that your grandma used and have the same spud peeled in the the same amount of time. Jan 19 '17 at 15:02

I would use a few non-magical alchemists and have them create poisonous gas, then use my mages' ability to control the winds to ensure the gas goes towards my enemies' army and doesn't disperse too much.

Should be a total massacre.

The benefit here is that depending on the natural wind condition, you need less and less magic the more the wind is already in your favor.

Note that this is of course a large-scale tactic that takes a bit of time and doesn't really answer what a mage would do in case of immediate danger.

I would thing about combining powers different way - have archers shoot a lot of arrows on enemy army, the take telescope and on long distace you can easily see individual arrow - select one from the cloud and just little bend its rear wings to hit king with extreme acuracy. Energy needed from mage is like bend feather. Eventually accelerate the arrow in its final approach to get more devastating and piercing effect - but only if you see, you will hit the target, so no energy spend on near miss.

Let catapult throw a barrel of oil to air above enemy army, balista to shoot burning arrow to the same area, just litlle manipulate wings of the arrow to meet its target and at the right time untie the rope fixing barel together, so the barel would break to parts, oil is spread over area and burning arrow (with momentary enhanced fire maybe) fly thru the cloud = instant fire rain / mass explosion.

Basicaly have physical way to get something heavy, fast harmfull near to enemy, then use minimal energy to slightly alter something on it to hit with unnatural precision and the just right time. Provide as much energy/material as possible with conventional means and manipulate it magically only when it is in nearly good position (which is not so hard to acquire) to have it hit excelent at the best possible point.

Use telescopes as much as possible and use them in periscope form, to have the mage out of sight. And use magic as small and short enhancement in final phase of attack, so it does not spend much fueal and is hard to detect, less to prevent. If you see, that there is effective countermeasure on target, just save it for next time - it would force defender to burn a lot of fuel to protect against mundane threads, which are not so effective, but could be, if the magic would be used on the last moment.

(I suppose, that the fuel is really expensive, so it pays of to spend a lot of mundane weapons/force to cover which one will be magically enhanced, if any and that the magicans are rare, so it pays of to send (and maybe sacrifice) squad of peons to prepare way for perfect attack).

Also using some "cheats" as create temporary inversion (fata morgana) on sky to see over hill enought to magically hit something out of LineOfSight would became common tactic. (Or shooting mirrors/polished plates to air, where it will be magically alligned to enable mage with telescope hit target behind corner/hill/other obstacle.

On the other hand a bit of magic used to little move some wood would enable to build really fast bridges over rivers/chasm and such, but throwing a lot of poles there in air (balista/catapult like style) and then magically alling them to make and arch, which would stand long enough to sappers climb it and fix it better with more ropes/nails and bouild the massive bridge over this small newly created - as the big problem of supporting first path would be magically moved away.

• yeah good idea about augmenting vision with mirrors/inversion Jan 20 '17 at 11:04

I would guess most mages would focus on air, as this is the most available element. they could create gusts of wind to change the trajectory of arrows, which would not require alot of energy. if more energy was available they could create tornado's above the enemies army, and in a duel or if there was an immense amount of energy available, they could try and remove the air from the enemies lungs or their surroundings, effectively choking them.

after reading all the other answers here i think a mage on mage fight would have a few stages.

1. be faster; kill your enemy in some way before they can react, e.g. really fast bullet/stone, or plain striking before your target is aware of you.
2. be smarter; outwit your opponent so you can kill them without them knowing what did the killing, or have them expend all their fuel on illusory attacks.
3. have more fuel; if you haven't killed your opponent with speed or wits you must be equally matched in these areas and thus overpowering is your only remaining, purely magical option.
4. be a better swordsman. if the above 3 steps have not worked it's time for your backup weapon.

Note that stage 1 through 3 might be over very quickly as neither side is going to be willing to expend all their fuel early on in the fight, and you end up with more of a witcher style duel, where quick spells are used to augment the melee combat.

the specific spells used are probably going to depend on individual preference, and the specifics of your rules for fuel expenses. it's not possible for me to say what takes more fuel, making a fireball out of a candle, or accelerating a few grams of (potential poison laced) iron to supersonic speeds.

The world you describe would use modern warfare with very accurate guns.

You state:

• "Magic" is the ability to control forces of nature (wind, water, flames, lightning) and inanimate objects.

• The range is how far the magician can see. Sight augmentation apparel can extend the range.

• They can control whatever they can see.There are no microscopes yet, so they cannot control individual atoms or molecules.

We've already acquired the first point in modern society. We can manipulate wind, water, flames, electricity, inanimate objects, etc. at the expense of energy (similar to your magical units). The only issue is that some manipulations cost more energy than others. Turns out moving projectiles is the cheapest (energy-wise) and most effective way to hurt someone.

The amount of energy you describe actually doesn't sound all that scarce. The amount of wind it would take to blow over a person is an estimated 70 mph, having that kind of energy 100 times over is not trivial.

We've also acquired the second point. Modern weapons can attack as far as they can see, and sight augmentation improves the effective range.

The third point is where I think the weapons become "very accurate". Not only can you apply force exactly where you want it, but from anywhere you can see. Now the mages don't need to carry weapons, because the world is their weapon. Most likely rocks.

Rocks are ideal because they're abundant and hurt when landing at high speed. Their abundence would generally mean the mage would not need to carry anything (except the magic source). Rocks can even be made and shaped from the ground through magic to accommodate environments and make them more deadly. Rocks aren't accurate at long ranges, but you don't need to fire the rock a long way to have a long range weapon.

Hit the target with a rock at their feet

So long as you can see a rock/solid object near your target you can hit them with it at little energy cost. Firing projectiles at long range would mean increased energy cost (to send it further) and decreased accuracy (once the projectile is moving too fast for you to see you can't control it anymore). Even if there were an energy cost associated with distance it provides your target little time to react or defend. A single costly projectile would be cheaper than many cheap projectiles, as well as increase survival chance.

# What Would a Duel Look Like?

There's actually historic examples to go off of.

A Western Duel

Both parties carry an extremely lethal weapon against the other. Since the ground itself can be turned into a weapon there's essentially no defense. Here the only defense is a good offense, dead people don't attack you.

Duels would be focused on how quick you can "draw", just like in the wild west.

This may not be very flashy or spectacualr, but if they are able to control physical objects, why not have them accelerate very small objects to high speeds (like bullets)? It would require comparably little energy and would be extremely lethal. That's why humans have always used kinetic energy to kill with.The more accurately you can steer your projectiles, the deadlier you are. Think of Yondu in Guardians of the Galaxy. Every Mage could just carry around pouches of whatever objects suit their potential requirements.

To make things more interesting they could also charge these small objects with something like heat, electricity(you said they can shoot lightning), etc.

Expensive fuel means that the tactics need to be above all else efficient. Assassins and snipers have been mentioned multiple times, this works well because the mage is attacking someone who does not know they are there, and therefor, will not resist. If you need to stop an attack than you are wasting fuel that does not damage the enemy. Of course you do want you enemy to waste their fuel, so at times it may be a tactic to simply throw wasteful attacks to ensure they run out of fuel if you think you have a major advantage and want to ensure annihilation.

Planning and preparation can be vital, traps are the best option

If the battlefield is known before hand, then creating traps could be highly efficient, using the nature of the trap to provide as much of the energy as possible. This can be as complicated as rerouting a river upstream using most of your mages, and using gravity to allow the water to build up the momentum to flush the opposing army away, or as simple as preplacing pebbles where you think the enemy will be so you have less distance to move them (bonus, using a pebble not from you location does not give out your location). Anytime you can put in a small amount of energy to spring or guide an attack and then let the laws of nature provide the bulk of the force, the energy required to block or deflect can be made greater than the original input.

A magician with precise enough control could be lethal with only small amounts of either water or electricity.

If they can create AC current, only 30mA applied through the chest for a fraction of a second is required to cause fibrillation, which in the modern world is almost certainly fatal without a defibrillator handy. If they can precisely target the heart somehow, the required current drops to about 1mA.

For water, keep in mind that the total lung capacity of an adult human male is about 6 liters. If you can fill a majority of that space with water, they will drown. A mage with a wagon full of water (1000 l, for example) could then kill 200 enemy soldiers, if they have the precision to shoot it at their mouths and force it down their trachea.

• Note that I was curious about fighting other mages. A skilled enough mage would just redirect the water away from his/her mouth. And the amount of concentration to force water into one's mouth would probably leave you vulnerable in the battlefield. Jan 18 '17 at 12:48

So I've given this a little thought and here is the most directly lethal thing I can come up with on short notice. (note that this answer assumes that your fourth rule does not extend to controlling the elements inside another person)

You said that magic includes the manipulation of lightning, I'm assuming this extends to electricity in general. Given that neurological impulses are just very small electrical signals a mage might kill someone just by making their brain go haywire, or even stopping all neurological messages, making the brain just grey meat.

Alternatively, a mage could control the water in another persons body, manipulate spinal fluid to sever the spinal column, or create a hole in the heart of an opponent by forcing the water inside it out, incapacitate or internal exsanguination would soon follow.

in essence mage combat becomes a case of "what can the mage control specifically" and "where in the human body can that do the most damage". which naturally leads to "how to i destroy or interrupt the functioning of the brain heart or spine".

• No, they can't control the elements inside one's body. They could make lethal elements enter some places of the body, but again, in a full blown battle I really doubt someone would stop and concentrate enough to do so. Remember his mage foe is very interested in killing him too. Jan 18 '17 at 13:03
• in that case it becomes the question of what costs more energy, acceleration of a bullet sized object to bullet like speeds, not giving the opponent time to react, thus making a human shaped gun. or creating enough distractions for the enemy to not accurately ascertain what to defend from. Jan 18 '17 at 13:16

Depending on the importance and size of the battle, it would probably be better to get the mages to cast one huge spell together and rely on AOE to do all the work than a single spell killing a few at a time.

A combination of wind and fire to create massive explosions(Assuming fireballs can be thrown else they aren't fireballs). Combining water and lighting to electrocute the enemy.

For smaller battles it wouldn't be worth using mages as the cost of normal troops would be much less than the cost of magical fuel.

## Self-enhancement

The best resource on the battlefield is the magician himself. He already has full control without having to expend fuel.

In an arena-style duel, augmenting one's own actions can be very successful whilst combat will be done via enhanced hand-to-hand with physical weapons. Large-scale spells will be a huge waste of fuel and complete overkill in a duel between two mages.

Speed-boosts can provide evasive manoeuvres and aggressive re-positioning. They can also accelerate hits to deliver quick, unforeseeable blows with immense force whilst minimising fuel spent. The magician can likely win a battle in seconds whilst conserving fuel if decisive enough with his actions whilst equipped with the right weapons.

Armour and clothing can be modified to be able to withstand large shock, useful for gloves to allow the magician to throw enhanced punches without damaging his own hands on impact.

• I specifically said there is no way to affect living bodies, including the mage's own body. Self-enhancing as you put it seems a lot like messing with metabolism and strenght in my understanding. Please clarify if I'm wrong. Jan 18 '17 at 16:19
• Not really. You can reinforce him with an exo-skeleton as a wearable that you can modify to be extremely strong but lightweight and then manipulate that. What I meant by self-enhancement is simply enhancing hand-to-hand combat, the quickest most direct way to incapacitate someone else, not physically modifying the body. Jan 18 '17 at 16:42
• well that would need a lot of multitasking according to the "no permanent spells" limitation. A spell only exists if someone is actively casting it. I see what you propose working if someone else is casting the enhancement. Jan 18 '17 at 16:47
• The spell can then only need to be active whenever he needs it to be active. It might require multitasking but what novice mage would engage in these kinds of fights? I'd expect the most skilled, those skilled enough to multitask their spells. Jan 18 '17 at 16:51

I like thinking about the energy requirement to use magic as the same amount of energy required to physically move an object, and the fuel as the available energy in a wizard's body. So, if a wizard wants to use magic to throw a rock, it tires him to the same degree as if he had picked it up and thrown it with the same restrictions. Therefore, a wizard could throw a molotov cocktail with his magic to throw it further than he could physically and it wouldn't tire him much, but if he wanted to pick up a boulder he may be able to do so, but would be physically exhausted by the effort and unable to do any significant magic until he rested. If he wanted to manipulate a smoke cloud that would require very little energy. One aspect of thinking of magic in this way is that it cannot be stolen (but possibly transferred if the mage wishes to give some physical energy to another). It would be possible that if the mage attempted to do something beyond his physical means he would die. So, could a party of 10 mages tear down a mountain? No way. Could a couple dozen mages working in unison push over a tree? Probably.

• Magic actually causes mental wear, but the "physical" fuel that is expensive is essential to the storyline. Jan 19 '17 at 11:58

sounds like mixed unit tactics would work best, knocking a squad down is not all that destructive, knocking them down just as they get ready to stop a cavalry charge would be lethal. One mage with 100 wind spells combined with cavalry would be a meat grinder.

Knock arrows out of the sky now only your side has archers. Or combine them with fire throwers and create a wildfire.

Turn solid ground to mud under your enemies feet to break up formations and charges.

Fight during a storm so your mage can turn lighting against your enemy.

Mages that can bend light would make terrific scouts.

Mages would be a nightmare during siege they could collapse walls by breaking keystones or cornerstones.

Being able to change the wind during naval battles would all but guarantee victory.

How much energy would making the enemy commander's helmet shirt and crush his skull take?

Mages would also be instant targets so having them protected by other troops would be important.

As for duels a good trick might be creating a invisible bubble around your opponents head that lets no new air move in, they would feel fatigued and wozzy and would eventually kill them, even if they did figure it out a gasping disoriented fighter is easy to kill. Or just pull the air away from their head and watch the vacuum effect knock them unconscious or collapse their lungs. Or for a more direct approach combine force of mind with force of body, add your mental power to a sword swing on top of muscle power,

I use a similar magical system and have discovered that telekinesis is fairly OP. It depends on how you balance resource usage (e.g. the relative cost of fireballs to levitation). Part of what allows the different mages to be relatively balanced, in my system, is that they are restricted in terms of what magic they can use, but the geomancers are particularly nasty.

They generally carry pockets of flechettes.

Aerodynamic, sharp, and they weigh practically nothing, so the magical cost to fling them is very low. You can put a marble or an arrowhead through a human body with relatively low amounts of energy, or spray a handful of them into a room like shrapnel, for the same 'energy' cost as tossing a baseball. I also have limits on AoE spells, but if thats not a limit, things like gas attacks are an excellent choice.

# Duel Scenario

IF wizards are much stronger than non-magic users..

The goal of a duel scenario between two (or more) wizards is to either escape, or kill the opponent wizard.

A wizard that is assigned to a squad of non-magic users likely has one or two assignments: i) Protect lives of the whole squad inc. from enemy wizards. ii) Play a pivitol role in the completion of some objective.

We could expect an enemy wizard to be able to kill off the entire non-wizard members of the squad. In which case things will degenerate into a wizard duel.

I also envisage that a duel between two equal & very powerful wizards, face to face, with no clear advantage at the start, would be over very quickly.

Each wizard has a number of offensive options which far exceed the range of defensive options available to each, thus leaving them with an impossible choice for pure defence.

However, each sort of action has a tell. Before you physically move, the corresponding muscles need to contract/relax.

• A keen eyed Wizard can infer what their opponent is about to do.
• A disciplined wizard can use unusual muscles to disguise their intentions.
• A wiley wizard can deceive with their muscle movements.
• Pretty much every wizard wears opaque and long flowing robes that give nothing away.

Some actions can be both defensive & offensive e.g a gust of wind would put distance between you and the enemy; Even if the opponent was able to resist being pushed, the equal and opposite reaction of the gust would push the caster away.

In general, the meta for wizard duels will never be static.

EDIT: I want to elaborate - A long time ago on late night TV (no chance I'll remember what program) there was a demonstration between two katana wielding swordsmen. Swordsman A, ostensibly, had a trick where they could shift their weight without tensing particular muscles in their foot. Swordsman B was therefore at a disadvantage because they couldn't move without broadcasting their intentions. The other idea between these sorts of duels (though I'm not sure whether only for practice, or if duels like this really existed) is that they were typically finished in 1 or 2 moves.

In a battle between two wizards then, you want to act swiftly to incapacitate or unbalance your opponent. Killing with magic isn't absolutely essential.

On the subject of fuel conservation.. I think it depends on the lethality of your magic. I would advise that it never makes sense to conserve fuel against another powerful wizard because the opponent could just use more fuel and kill you off (and maybe take your fuel).

So, on meeting another wizard your objective is no longer to conserve fuel and keeping on top form. The objective becomes kill the other wizard, save your own life, try to save your allies, and take whatever fuel is remaining. Then, go home and recharge.

On the other hand, if magic isn't especially lethal, then you should think about conserving your energy. Something along the lines of wing-chun, perhaps: https://en.wikipedia.org/wiki/Wing_Chun#Relaxation .