People on my planet can use magic in some way. Some can only throw sparks from their fingers and some can cast thunders, the same with fire, water, air and arcane (telekinesis, teleportation etc).

Technology is Earth-like medieval times. People who are gifted with great power are the ones who rule the countries and similar amount of magical power is passed on to offspring, so two poor-gifted ones can't have children with great power. This resembles feudal system - peasants stay peasants, nobles stay nobles, peasants work for nobles.

Magic is used in a battlefield but has not entirely dominated it. The most powerful are known for instanly killing 100 people in the battle with one spell, yet are left tired (like sprinting 200m is for a trained soldier - not exhausting, but still feeling the run). There are units who use only magic, but regular soldiers might use magic of their own during the fight (like swinging the sword with right hand and casting a spell in the other).

One day the planet was attacked from space by an alien species that posses technology similar to ours with some differences like FTL, advanced AI (but not self-aware). Armements are roughly similar to ours (no lasers, no death-rays, slightly upgraded bullet-based guns).

What could be the possible outcome of such a war? Do you think magic world could fend of the attackers, or eventually the aliens would prevail?

More info (includes edits):

  • Medieval soldiers are used to fighting in a battlefield, while the alient species use modern day tactics.
  • Alien species have no idea about magic and see it for the first time.
  • Wizards can combine spells together to make one but more powerful.
  • Alien invaders kill everything that moves, their true motives are unknown (there's an assumption they want to kill significant amount of people and enslave the ones that are left alive)
  • Wizards can create a magical shield, which defends the caster or the place/person caster picks, but it has some durability, just like real shields + it's tiring for the caster to maintain the shield on. Combining these spells could create a city-big shield.
  • Weather conditions can't change magical projectiles's trajectory
  • Magical projectiles will travel any given distance unless encountering an object on it's way
  • Aliens don't use AI robots instead of organic soldiers.
  • Telepathy is a valid form of communication between natives.

EDIT: Let's assume a scenario:

Aliens already attacked the planet, causing some damage. They sent two Star Destroyer-like ships, the rest of the fleet is still on hold in a further orbit (not relevant right now). In one of the countries the most powerful wizards in each major city combined their spells and attacked the ships from the ground completely destroying one of them and dealing some heavy damage to the other one, that it has to retreat. How would aliens possibly react to such a counter attack?

  • 1
    $\begingroup$ What is your question? $\endgroup$
    – fairytale
    Aug 7 '15 at 11:53
  • 1
    $\begingroup$ Depends. What's the goal of the aliens? Human elimination? Planetary colonization? Acquisition of slaves or food source? $\endgroup$
    – Frostfyre
    Aug 7 '15 at 12:29
  • $\begingroup$ @Frostfyre - if they kill anything that moves - according to the OP -, I would say "total annihilation for the sake of acquiring a new planet and hence its natural resources, thus settling a new colony", but I think it's better if this is specified better in the question :P $\endgroup$ Aug 7 '15 at 13:22
  • 1
    $\begingroup$ @theadimar21 is that kind of magic capable of creating city-sized shields which could stand repeated bombing from - let's say - modern AC 130? If not, the outcome would be quite easy to predict - provided that your magically enforced population does not have any efficient anti-aerial counters: in my humble opinion, air supremacy could actually raze the magic driven world without too much effort - not mentioning nukes and so on. Seriously, it all depends on the level of "protection" the magic can provide and for how much time. I could elaborate more in a complete answer... $\endgroup$ Aug 7 '15 at 13:25
  • 1
    $\begingroup$ Wizard can cast shields and can also combine their spells, so creating big-ass shield is possible. $\endgroup$
    – user11471
    Aug 7 '15 at 13:50

In response to my question about the aliens' goals in approaching the planet, you stated that "Alien invaders kill everything that moves." This suggests they're only interested in the planet's resources or they intend to terraform the world for their own purposes. In either case, they don't care about the death toll of the native populations. Since they have FTL capability, there's also a chance that they can't recognize the native populations as intelligent (there's a discussion on identifying intelligent creatures here).

Because these aliens don't care about the body count and they may not recognize the natives as intelligent, there's one plausible outcome to this scenario that exceeds all others: total annihilation. The first order of business is to remove the pesky native populace, since they're in the way, and the best way to do that is with some form of kinetic bombardment (drop a lump of metal from space).

In short, the aliens win when they arrive at the planet, before the natives even know they've been selected for extermination.

  • 2
    $\begingroup$ Yeah, kinetic bombardment would be a good counter to unlimited range of spells. Thank you for your thoughts! $\endgroup$
    – user11471
    Aug 7 '15 at 14:21
  • $\begingroup$ Totally agree. I just don't know if kinetic bombardment would be considered "overpowered" by the OP :P EDIT read now the comment. Okay, totally agree without the "just don't know" part :D $\endgroup$ Aug 7 '15 at 14:23
  • 3
    $\begingroup$ +1. This should be the #1 way any starfaring race deals with less technologically advanced native species. The Na'vi shouldn't have stood a chance against a competent human commander. $\endgroup$
    – March Ho
    Aug 7 '15 at 14:59
  • $\begingroup$ @MarchHo youtube.com/watch?v=kXraSkgssFk $\endgroup$
    – Ajedi32
    Aug 7 '15 at 17:03

I'm gonna take a moment to try and wrestle the problem by redefining and talking through it a little bit.

Also, please forgive my typos, since this is long.

The Attackers:

They have FTL, and comparable armament to us. To get my head around it, I'm thinking BSG, maybe Cylons. They had an extremely similar goal when they attacked the Colonies - kill almost everyone. Even if they want to enslave a portion of the population, they still have a very low regard to the lives of their victims, even outside of the theater of war.

They will start with a nuclear / orbital bombardment, period. Even if they don't have nukes, they will nudge a passing asteroid or few (or hundreds if they have time). They won't kill every person, but they will definitely thin the urban populations and scatter the industry of the planet.

After they feel they have softened their opponent, then they will form an aerial assault. This is will look like the Gulf Wars, Korea, Vietnam, or the Luftwaffe. They will fly around dropping bombs on things that look industrial or important in some way. They may even re-bomb thing they already bombed, simply because it still looked too intact from 35,000 feet. They will probably get there first taste of magic at this point, but most caster will have trouble hitting something moving at super-sonic speeds.

Once everything that looked like a city, town, or fortress was leveled, they would send in the troops. The troops would need to capture more people than kill, if only the get the scoop on where all the other survivors went. The Aliens would start at the major cities, since that's where survivors would be wandering around, and then fan out from "green zone" like base-camps, securing larger and larger chunks of land mass until there was nothing left.

The Defenders:

At first, they may not know why death and destruction are falling from the sky. Maybe they have some seer stones or clairvoyancy that alerts them to the Alien threat. At this point though, they gonna have some hard times doing anything about it. Some cities can get shielded, but there's a ton more asteroids / plutonium available then high-level caster, at least with medieval population densities. Plus, it only takes one guy or shift to mess up, and the whole city becomes a crater, narrowing your talent pool. Eventually the noble class would be driven underground.

The peasant class would own the planet now, although they wont have the same talents, they may still have some hope.

The aerial bombardments would be difficult to defend against, since they will actively hunt and report large bands of survivors. The Aliens will especially target any occurrences of magical resistance, and may even withdrawal to more heavy ordinance on the area if they lose any aerial assets. The peasants would become nomadic. However, like genetics, there's a lot of latent and dormant phenotype stuff (Dammit Jim, I'm an Engineer, not a Biologist!) that could be brought out by the stress of the situation. Even though it is stated that there wont be champions, It is extremely difficult for me to imagine this not being the case. What of all the Jon Snows and bastard babies who don't think they have greatness, right up until they do?

Once the troops land, its gonna get hairy. I think that two star-destroyers compliment of soldiers, while being quite a large force, cannot effectively hold a planets worth of land mass, so we will be a ton of guerrilla warfare and rebel bases spring up and going down in a nomadic fashion.

Captured defenders could easily work from the inside, doing sabotage and telepathically sending information to the resistance. The Aliens would be wise to get some sort of test devised, such that they can execute anyone with magical talent before letting them into the green zones.


Now we have a ground war.

If the defenders win, it is because the noble class effectively survives the initial bombings in enough number to be present and casting during the ground war AND they manage to capture Alien tech. Once they can level the playing field, probably in some Hamburger Hill / Imo Jima type battle, they can start their own aerial bombardment, nuke throwing, and other shenanigans.

If the Aliens are going to win, they will have need to take the casters out before the ground war, AND avoid over-extending their resources such that they can never be overrun by guerrilla fighters in such a way the advanced tech falls into the hands of the defenders.


It could go both ways, since magic can be a powerful equalizer in a ground war.

The Aliens will have to be damn sure they don't make any strategic missteps, because ( magic + being outnumbered ) could cause them to lose Advanced Technology to the defenders, and that instant that happens they will probably lose the war.

  • $\begingroup$ Thank you! This was a really interesting question, and I enjoyed answering it! $\endgroup$ Aug 7 '15 at 18:27

Since there are not so many details on some questions I consider relevant, I will reply considering different scenarios. The question is really vast and difficult to answer, so I will try to reduce my thought in a nutshell:

Range of magical attacks

unlimited range

If the range of the magic is considered unlimited, then the aliens would have a really bad time invading the planet. If your enemies can systematically lightning-strike/set to fire/freeze your battleships while being kilometers away from the battlefield, you would be lost just the moment they enter the atmosphere. In that case, aliens should just switch tactics and go for less armored, faster battleships in order to retaliate effectively while avoiding being targeted like flies.

This scenario is more favourable to magic users, provided they have enough wizards to sustain a continuous attack on the alien menace (and provided that orbital bombing is not allowed or too advanced according to OP).

long but not unlimited range

If magic can be cast with the same range of a modern rocket launcher, the odds should be equal for both factions - since the resources would be almost at the same level. Teleport vs. FTL, spaceships and heavy bombers vs. "rocket launched" fireballs, both infantries could be targeted from "artillery". In case orbital bombing is not allowed, this could be the most equilibrated scenario - provided that wizards can last long enough to endure the battles. The big difference here would be tactics, and whoever has the best tactics would prevail. This means that medieval people should update their thinking and start adopting "smarter" choices in order not to have their soldiers crippled from the enemy artillery.

medium (a.k.a. modern assault rifle) range

In this specific case, the aliens could gain the upper hand quite easily, at least against most of the armies. If the aliens have starship/air support, it's likely that soldiers would be sufficiently weakened by continuous bombing or air raids to be disposed of quite easily from regular alien footsoldiers. Moreover, this scenario would prevent AA spells to work, thus letting the invaders the complete air supremacy and leaving your medieval society at the mercy of carpet bombing and (why not?) nuking. Moreover, since the most powerful existent spell can "only" dispose of 100 men, a nuke killing thousands of people would definitely destroy every hope in the invaded population - much like a psychological effect - after which every king would probably try to negotiate the terms of the defeat.

Following this line, the only remaining tactics could be guerrilla, much like vietcong in Vietnam wars, but I wouldn't expect this to be enough to defeat the aliens.

close range

See above. Even worse than medium range scenario.

Defensive power of magic

If the magic is powerful enough to create city-sized shields (by, for example, unite altogether 100 magicians to keep it active), then carpet bombing would be a lesser problem and there would be chance for a more equilibrated fight.

A nuclear bomb could be however too much to sustain and the psychological effect of having a city completely destroyed by only one bomb despite the shields could completely cripple the fighting will of the population (the same psychological effect which caused Japan to surrender in WWII). If this is not the case, the two factions could have a more equilibrated stand against each other.

Reaction of the aliens to magic / reaction of the magicians to aliens

Okay, aliens have never encountered magic before - fine. But as long magic is not too superior in respect to their technology, they would simply analyze it and rationalize it as a different - yet unknown - technology and consider it no more and no less than an unconventional weapon. Only if magic proves to be far more powerful than their resources, then this would turn the tides - since the aliens would be facing something completely unexpected. Just consider that, from the medieval population's point of view, even aliens would use magic, quoting Arthur C. Clarke, and so they could perceive the aliens as deities using a magic more powerful than theirs. Obviously, even the other way around is possible - but as far as I got from the OP, the first scenario is more likely.

EDIT a new information has been added while I was writing my reply :D I will edit it if there are any relevant comments turning the tide of my answer ;)

  • 1
    $\begingroup$ modern assault rifle range compared to unlimited range is pretty small ;) thanks for your thoughts! $\endgroup$
    – user11471
    Aug 7 '15 at 14:31
  • $\begingroup$ Well, I can rearrange the answer to include some "long-but-not-unlimited-range" like modern rocket launcher ;) $\endgroup$ Aug 7 '15 at 14:41