For centuries, on the day the moon would turn a blood red, a portal would open across various worlds. Chosen warriors from these worlds would enter the portal, usually at most five people per world, then enter a realm that was the center of various dimensions, and where a tournament unlike any other would take place. The purpose of the tournament is simple: to find the very best warrior across multiple realities.

During the tournament, warriors from across the realms would do battle in one-on-one combat, and if they win, they would go on to face their next opponent the following day after getting their injuries healed by the healers the tournament employs. The match-ups are almost always random, with all of the warriors being divided into various brackets and the champions of these brackets going on to the finals, and the locations of the fights are never the same. For each match, the two warriors are teleported to different locations across dimensions; sometimes it could be a valley, with the warriors having to wander through it just to find their opponent, though in these cases both warriors have to make an active effort to find their opponent or else they are disqualified, sometimes it can take place in a decaying building that is about to collapse, or even in a dojo with the warriors being only a few feet apart. And at the end of each match, when the judges declare that a warrior can no longer battle, the winning warrior has the option of either killing their defeated opponent, or letting them live. Most people chose the former.

With the tournament going on for centuries, rivalries have formed across dimensions, as a lot of races are selected again and again due to producing such excellent warriors. One such rivalry is with the Fujins, a race of humans that have developed the ability to harness the wind, and the Agnis, another race of humans from a different world where humans learned how to manipulate fire.

The Fujins can create powerful blasts of wind strong enough to lift a man off his feet and send them flying. They can also use the wind to jump higher than trees, though they can’t fly, use the wind to help them land from any height without any fear of injury, and can channel it in a way that can let them condense it into a “blade” made of wind that is strong enough to cut through metal. They can also mold the wind into any shape they want, such as say, a ball of wind that they can ride on and let them travel at great speeds. Finally, if they have enough time and can concentrate hard enough, they can manipulate the wind in a way that would create “sharp” breezes that slowly wrap around an opponent without them noticing, and then, once the user literally feels the “breezes” are close enough, with a thought, they can slice a man to ribbons; sometimes killing their opponent, but always leaving very serious wounds on them.

The weaknesses of the Fujin are that, while their “magic” takes up a brunt of the effort, it still takes effort to manipulate the wind for attacks, and for the more deadly attacks, like the “sharp breezes” or trying to suck the air out a person’s lungs, it takes intense concentration and also requires their opponent to stay in the same general spot for at least a minute. Also, the harder it is for them to breathe, the harder it is to use the wind.

The Agnis can create powerful torrents of fire hot enough to melt steel, with enough time. They can mold their fire into various shapes, like a whip made of pure, blue flames, or a lasso of red falmes that can wrap around a person’s throat and burn them at the same time. They have a general “heat sense,” as in they can feel just how much heat an object emits, and even see the heat they emit if they “switch” their vision to a kind of thermal vision. If they have enough time, they can form special balls of fire that seek out the biggest heat source in an area. Finally, they can “suck” the heat out an area and condense it into massive fire constructs, like a massive ball of fire that they can launch from their palm and incinerate their surroundings.

The Agnis' weaknesses are that the more complex the attack is, like “sucking” heat or construct creation, the more concentration and time it takes to form it. And while their “magic” lets them be heat resistant, it can only protect them for so long before they start to feel the heat, like minor burns that can get worse as the fight drags on. They will have “cool down” periods between attacks, anywhere from a few seconds to 30 seconds depending on the intensity of the attack, that way they don’t wear down their heat resistance so quickly, and it can recover as well.

Warriors from both the Agnis and the Fujins have fought each other in this tournament for almost as long as the tournament has been around. The only rules of the tournament are that the weapons you can bring are those you must have trained extensively with, so no brining a weapon you think might come in handy against someone from a race whose weakness you know, and in the event one warrior tries to run and hide, whether it's to try and heal their injuries or come up with a different strategy, they must come back to fight the other warrior within twenty minutes, with a “timer” appearing in their heads provided by the “host” of the event, or else they automatically lose. Keeping in mind all of the previously stated information, I want to ask: what kind of tactics would these two races develop against the other?

  • 2
    $\begingroup$ Agnis: "you and me, mano a mano!" Fujin: flies away. $\endgroup$
    – user6760
    Jun 13, 2020 at 11:38

9 Answers 9


Quantifying the Opponents

Before suggesting tactics, let's try to come up with a model that lets us broadly explore the limits of Fujin and Agnis abilities.

Fujin appear to be telekinetic. And by that, I mean, they seem capable of creating a certain amount of kinetic energy at will. Agnis appear to be pyrokinetic: able to create thermal energy.

The Fujins can [...] use the wind to jump higher than trees, though they can’t fly.

This helps a lot with estimating their limits. Assuming, like human beings, the Fujin have a peak "deadlift" strength that they can exert in short bursts, and a lower "carry" strength that they can exert casually.

The average human jumping height is 16 inches. In this case, it's safe to assume that nearly all of the jump height is from Fujin powers. The potential energy gain going from the ground to a 10 meter (~30 foot) high tree, for a 100 kilogram person is $E = m g d$, which is roughly $100 \times 10 \times 10 = 10,000$ Joules or 10 kilojoules. If this can feet can only be kept up for a few seconds, we could also say Fujin power is limited to "deadlift" peaks of 10 kiloWatts.

People capable of benching 100 kilograms typically can carry a 22 sustained kilogram load. Passing this along to the Fujin, they'd be capable of a casually using 220 Watts of power. This is less than the amount of kinetic energy power $F = m g \approx 100 \times 10 = 1,000$ Newtons per second (Watts) needed to fly. So, Fujin can not fly (but they can jump impressively).

Fujin can [...] create powerful blasts of wind strong enough to lift a man off his feet and send them flying.

At 220 Newtons, a Fujin can provide a good punch. It is capable of knocking a person down. And a Fujin could easily wind-up the much stronger 10 kiloNewton haymaker.

Fujin can [...] mold the wind [such that] that they can ride on and let them travel at great speeds.

Fujin can run on the ground, boosting their own running speeds with their power.

Fujin can [...] channel it in a way that can let them condense it into a “blade” made of wind that is strong enough to cut through metal.

The energy required to cut metal is approximately equal to the product of yield strength, cut area, and the thickness being cut. $E = \sigma A s$. A soft-ish metal has a yield strength around 40 megaPascals (MPa). How big a slice can be made in 1/4 inch (8 cm) of metal? $220 / (0.08 * 40,000,000) = A$. A 4mm radius light punch, or a 3cm radius heavy punch.

Agnis can mold their fire into various shapes, like a whip made of pure, blue flames, or a lasso of red flames

Nitrogen ionizes between 14 and 16 electronVolts per atom. 1 eV = $1.6 \times 10^{-19}$ Joules. 1 mole of gas is 22.4 liters. 1 liter is 0.001 $m^3$. Assuming a rope $1 \over 2$ mm thick and 10 meters long would be 539 Joules, which we'll says is Agnis' "casual" load.

Agnis can [...] create powerful torrents of fire hot enough to melt steel, with enough time.

The amount of energy required to melt steel is 1,500 C (melting temperature), 0.49 $kJ \over {kg C}$, times 237 ${kJ} \over {kg}$. To slice a 1 kilogram chunk out of a block of steel, then, requires a "deadlift" capability of 174 megaJoules, which is way over the Fujin. Trying something a little smaller, a 1 gram cut - 174 kJ.

Agnis can [...] “suck” the heat out an area.

Think it's fair to say Agnis can add or remove heat energy from things.


Fujin: 220 $W \over {m^2}$ "casual" strength; 10 $kW \over {m^2}$ "peak" strength (only sustainable for a few seconds). Can only add or remove kinetic energy from things.

Agnis: 540 W "casual" strength; 174 kW "peak" strength. Can only add or remove thermal energy from things. Can also detect thermal energy at a distance.


Agnis are stronger, and have very useful detection capabilities. Fujin are more maneuverable, and have finer control (being able to manipulate things without melting them).


Blind fighting favors the Agni, who can see in the dark. If an opportunity arises to fight a Fujin in the dark, they should.

Fujin caught in the dark should try to kick up dust that will block thermal vision as readily as normal light, evening back up the fight.

Fujin have the fine control to create defensive structures. It's probably a good idea for them to spend the first few seconds before a fight with an Agnis to change the environment to their favor (precarious limbs, blocked passages, taking high-ground)

If caught in the open, and the battlefield is humid enough, Agnis can lower the temperature to create instant fog covering their escape.

Battles in ruined structures favor the Fujin, who can move quickly and safely over the uneven terrain. Agnis should try to set the structures on fire, if the material allows it. Stuck in such a situation, the Agnis best strategy is to get a few hits in early, then try to run down the clock.

Agnis have a tremendous advantage over Fujin when the battlefield is plentiful in combustibles : chemicals, gas under pressure, or dry woodland. Agnis, protected from heat by the own powers can start forest or structural fires. Fujin, already a bit weaker than the typical Agnis and who also need to be able to draw full breaths to keep their strength, will be even further weakened in these conditions. Fujin caught this way may choose to use their powers to feed the fire, hoping to trip the Agnis up and create better conditions for scoring at the end of the game.

Valley fighting. Agni should do their best to take a good vantage point, find their Fujin opposite, and set up a trap (such as lighting a fire in a deep box canyon). The goal is to pin the Fujin down into a one-on-one fight in clear terrain, which favors the stronger Agni. Fujin, on the other hand, should use their fast-moving ability to get a sense of the land before searching for the Agnis. Given Agnis ability to see heat, Fujin should assume their position is known, and therefore figure out ways of drawing the Agnis into terrain that'a favorable for the Fujin (lots of stones, wet wood, or dust).

Dojo fighting. Fujin should favor steel nets. Because of Fujin wind powers, they can manipulate these area effect weapons at a distance, rolling up the net into a whip (possibly with hooks), or capturing and restraining an opponent for a killing blow. In a close fight, these weapons allow the Fujin to control most of the field. Agni should favor smoke bombs. Agni can use their power to set the smoke aflame, stripping the air out of the room and simultaneously stunning and weakening a Fujin opponent (who can't draw breath to use their power). The air blast will also most likely snag a net, making the Fujin weapon ineffective.


You know what really feeds a fire? Wind. Wind can help a fire spread, make it spread in a different direction (or even snuff it out if it's blowing a certain way), or even cause it to suddenly get bigger due to the influx of oxygen. There's a reason fires aren't safe in windy conditions, and a reason why many bush firefighters hate high winds.

Now all of a sudden your Agnis have to worry whenever they fight a Fujin because they no longer have total control over their fire. A Fujin can cause an Agni's fire to suddenly swell, peter out, or worse yet blow back onto them. One would think that when performing fine-scale tasks like making a whip out of flames, concentration and control would be key. And that while they might have heat resistance, suddenly being buffeted by unexpected flames is going to be dangerous, especially if there's some degree of endurance in maintaining the heat barrier. Especially if the fire or the smoke it produces does something like burn their eyes, nose, or other vulnerable mucous membranes, which are probably going to be harder to protect than regular skin. Or just ends up suffocating them.

Don't play with fire, kids.


Cat and Mouse. Fire Slow. Wind Fast.

Fujin wants to fight in the dojo where the opponent has no time to prepare. Launch a bunch of wind blasts to starve all their fire attacks of oxygen and knock them through the wall/floor/ceiling.

Agnis wants to fight in a valley, where their opponent is far away. They pick a good hiding spot, and get to work feeding heat into the nearest source of rock in order to create lava weapons. For example balls of lava for launching or a 40-foot lava whip to slice the other guy in half.

Note: Why spend half and hour forging a lava whip when a fire whip is so much faster? The reason is the difference between sticking your hand in the $250^\circ$ oven and sticking your hand in the $100^\circ$ kettle. Yes the air in the oven is much hotter but theres a lot less of it. You can stick your hand in the oven or run it through the firey bit at the top of a bonfire easy peasy. But stick it into the kettle or into the coals at the bottom of the bonfire and your skin will start to melt. Same with the lava whip. The lava whip is made of heavy stone while the fire whip is made of light air. They are just as hot but the lava whip carries a lot more heat in total.

Fujin needs to find Agnis before they get the lava weapons up. They fly around and try and find the enemy.

Once Agnis has their weapons they have the advantage. Their weapons do not need oxygen, so they cannot be extinguished with a wind blast. They are also much more dangerous in the short term. While you might get concussion from a well timed wind blast, your opponent will be sliced in half from your lava whip.

Now Agnis tries uses their heat vision to locate the opponent and ambush them.

If Fujin realizes the weapons are formed they go on the defensive. They have the mobility advantage, but if they fly to the opposite side of the battlefield Ignis will just start recharging their weapons.

The difficulty is you cannot go from recharging your weapons to immediately wielding them. So recharging leaves you vulnerable.

Usually battles go one of two ways:

(a) Fujin locates Ignis before the weapons are up and beats them easily.

(b) Ignis gets their weapons up. Fujin realises, retreats, and it becomes a mind game. How far away is he? Should I recharge my weapons? Or is that what he wants me to do?

Type (b) can last hours or days, and are often settled by who gets hungry/thirsty/tired first. Some fighters specifically train their endurance for this.

The most interesting and dangerous battles are (c) where Ignis has enough time to create say a 10 foot lave whip instead of a 40-foot one, but has not revealed themself yet. Is he in that cave over there still forging? In that case I should sneak in and murderkill him. Or is it a false trail and he's waiting for me to go in the cave and then ambush me? In that case I should either sneak around or spring the ambush.

Depending on how that goes a 10-foot lava whip versus a Fujin of equal skill is usually considered a fair fight. This is what every true warrior wants to happen.

Some battles follow a warrior's code where Fujin allows Ignis enough time to prepare a 10 foot whip and then they duke it out to the death.

I know you said the warriors prefer to kill each other. But if I am a fighter trying to become The Very Best Like No One Ever Was, then I might prefer to not kill my opponent if I deem the battle was unfair. For example if I am Fujin and we fight in the dojo I would leave my opponent alive so we get the chance to fight again on a level playing field, and determine who is actually the stronger.


The fujins have far better ranged attacks, a blade cutting steel is way superior to a ball of fire.

My arm, left arm suffered third degree burns. Getting such burns requires the skin to be in full contact with the flame for a lot of time..... A few seconds are not enough, a fire ball will cause mildly blisters while a blade made of wind which can cut metal...well it's a different story.

If the Agnis want to make any use of their mighty fire balls, they need a lot of oil to throw in the face of their victims and then ignite it.

Human skin takes a lot to blaze but once it does people become living candles, fat melts and erupts from the skin just to be ignited by the heat and oxygen, making the entire skin into charchoal and the fat under it boil. On limbs it is not lethal and can be heasily healed if infections are prevented ( I lost most of the skin off my arm, it fell of as pieces of dark solid charcoal but it grew back in 3 weeks) .

However on the face...oh my that's a different story, if the heat doesn't kill the brain by making it boil, the lack of oxygen sure will.

Also getting tired is not s serious weakness for the fujin, unless they are not human or incredibly different types of humans. People are realistically the fittest creatures on earth second to Tuna.

If I was a fujin and wanted to keep myself alive while having a chance go kill my adversary I'd just bring with me a one use shield to block an initial oil assault or initial " boom IMA melt you asshole" and then throw my wind blade when the hit is certain.

Mind that real duels melee or ranged are always short and don't take more than 20 seconds. Hollywood or anime duels are nonsense and ridiculous to the point of being amusing. A real duel rarely even hits the 20 second mark.

If I was an agnis I'd just try to blind my enemy by taking as much distance as possible and setting all terrain on fire, it takes them one split second to split me in two, but if they don't see me because their vision is blocked by flames then I have a decent chance to survive. For a weapon I'd just pick a bottle of oil or a molotov, if not possible then a pilum or any small spear to throw would be fine. They won't see it Coming through the flames.

If the fujin tries to fly up high with their jumps to see where I'm hiding, I have a chance to throw something at them...they can't dodge anything mid air, you said they can't fly. So if I see them mid air, they can't escape my spear.

But preferably I'd be a fujin, better chances to survive and harder to mess up.

You are really comparing flamethrowers to ak47's here....and we all knoe who's more likely to win.


temperature doesn't matter, even if the agnis can melt any metal or any surface, their fire balls are still useless alone.

Humans can touch molten metal without getting hurt if they are quick enough.

Oh and fire DOES NOT EVEN HURT once the fire has burned the pain sensors, the burned victim feels no further pain.

Agnis = trash tier , bad fighters...set them to fuel vapor ships instead.

enter image description here

Here's a picture of a fujin slapping some stupid agnis



Dust has the potential of becoming explosive when exposed to fire. If the Fujins can create a dust cloud around the Agnis, if the Agnis try and use their abilities, the very air around them may explode.

Dust would also block vision allowing the Fujins to hide.


This is a battle, and magic or not there are fundamental principles of battle that still apply. In particular, it's generally considered a lot easier to attack an enemy's supply or source of power than it is to attack said enemy head on. This is the foundation of siege warfare and been used in most major wars for as long as my history lessons taught me, anyway (possibly excepting early naval warfare, but never mind). Plus I'm sure Sun Tzu would have some choice words on the subject, but I haven't read up on him recently.

Anyway, I'm going on the assumption that all this is happening in a particulate universe - the magic forces are being used to affect light particles (air and combustion fuel), rather than attacking the opponents directly with an actual magical force that only resembles wind or fire. The particle idea is backed up by your references to breathing,

With the above two considerations taken into account, here's how the strategists on either side should be thinking;

  • Fujin: manipulate the fire. They can use their wind to counteract the (intended) effects of the fire - obvious choices being starve it of oxygen, blow it somewhere else, blow the smoke around to create smokescreens, scatter the fuel etc. More interesting choices (plot twist) would be to give the fires extra oxygen/air so they require more fuel to sustain, thus tiring the Agnis' magic and weakening them (risky strategy but make for an interesting story). "In the event the enemy tries to run and hide" then becomes more common and predictable, and the Fujin can chase them and use more 'conventional' attacks while they're weakened.
  • Agnis: Disrupt the wind. They can create or suck heat, in a localised fashion. Result, areas of high or low pressure air. Which causes wind ... this is a direct attack at disrupting the enemy's weapons as the Fujin are going to find this sort of attack much more difficult to dodge (they could get out the way of an oncoming fireball, but probably wouldn't even see a heat-suck away to their left and therefore wouldn't expect all their efforts to divert off-target). Finally, if the Fujin are using their wind constructs to ride on and travel around, a bit of turbulence would really make things interesting (try a coordinated Agnis attack with one setting a traditional attack or ambush and the other using heat-suck turbulence to drop them into it).

And there you have it, both sides using or disrupting the other side's weapon!!

Also, in this day and age of publicly ashaming or blaming people for things they didn't intend to do (scuse the quick rant there) I couldn't help noticing that there's an event host? What if either side manipulated the other sides weapon to unintentionally attack the event host (who we assume to be partly invincible) and embarrass them? Again an indirect attack, and probably an unpopular one if found out, but would make for an interesting story...


This sounds like two opponents who would have a fairly hard time defending against each others attacks. When a metal cutting blade of pure air is coming at you, a fireball isn't going to do you much good. But when a fireball is launched at your face, blowing more oxygen at it is the last thing you would do.

Therefore I would argue it's not the one with the best attacks against the other who will prevail, but the one with the best defense. The problem is though, the fighting style should be fairly versatile, as this is a tournament style fight. If you train just to defeat one of your opponents, another might hand you your own behind.

I would imagine the Fujin to be extremely mobile and agile, dodging any attacks coming their way. They would likely combine their wind attacks with Kung Fu like martial arts. As so it happens, when fireballs come flying, getting out of the way is your best option. Especially if your powers would just make it worse. The first attack that springs to mind when using wind powers is suffocation. Blow away the air around someone's head, or reduce the air pressure around them, and not only will their lack of oxygen slow them down significantly, keep it up long enough and they might not breathe again. Without osygen to burn, their fire attacks wouldn't do much good anyway. When developing air attacks, don't just think about the air that is there, but the air that isn't there is just as important.

The same would go for the Agnis. If you say they can "suck" the heat out of something, I'm assuming you don't mean only up to a cozy room temperature. If they fight with heat, it could go hand in hand with cold. If they lower the temperature in their surrounding while using their powers to simultaneously keep themselves warm, their opponents would at a disadvantage, and frozen ground would make it difficult for his opponents to move. As for defense, a large wall off fire around themselves would definitely disrupt any air attacks. Because as you know heat rises, and rising air means a pressure difference going upwards, meaning any air attacks will be disturbed by that difference and deflected upward, and they could dodge attacks with minimal movement.

I could spend hours coming up with different attacks and defenses you could give your fighters, but I'm thinking you have that down from your question. Bottom line is think about the possibilities that are beyond the obvious. Heat and cold, air and the lack of it. Combine physical techniques with magical ones.


Are Fujins able to increase wind's power? What about breathing process? Can he accelerate/increase amount of air absorbed by Agnis? If so, what about simply exceeding one's lung capability and bursting it? I think that would be clever way to kill oponent without direct combat.

What about using strong wind attacks all the time keeping Agnis on distance? Since it's magic environment, you are kinda setting the rules.

How much reach Agnis/Fujin have? If Agnis can't really use any attack effectively without closing up on enemy, it's tactic would involve every possible way to do so. Despite being direct, Agnis would need to learn go to be silent, stealthy and use some kind of bindings/traps to pin it's enemy and crush it with brute force without leaving other any mean of counter attack and reaction.

If Agnis is found out and battle is out open, he stands no chance against Fujin other than maybe burning everything down(if it's closed space) with maximum power (so enemy's will shatter). Perfect weapon for Angis would be long chain (strengthened to withstand these cuts you were talking about). If Agnis is somehow resistant to explosion, he could use chemicals as well (gun powder or some advanced stuff).


If fugins can only work the wind as long as they breath and an agnis can take thermal energy from something the best scenario to an agnis is set everything on fire but himself. EVERYTHING. The smoke that results from this will eventually get to the fugin and will incapacitate the wind power. Eventually C02 will kill him. While you, smart agnis, drink a soft drink, sit down, in your safe place without fire.


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