If ten percent of humans were changed to various humanoid species, some more monstrous than others, and if ten percent of those changed, so one in a hundred, were to completely lose their minds in the process would it cause the collapse of civilization on the short term? And if, on top of that, a diaspora of humanoids, of the same species as the 'turned', from another dimension, were to invade ours, how much would it accelerate the decline, if there is decline at all?

Assume a portion of the refugees are user of a hard magical system that puts them, at least, on par with earth's military capability (except nukes).

Edit: All ten percent starts they changes at the same time period. The changes happens over 24 hours but, like larvae, they suffer from intense hunger pains a month or so earlier, gaining quite a bit of weight.

Their power levels range from hunter gatherers and farmers to powerful warriors that would require a lot of preparation, bodies and luck to take down.

Dangerous fauna also cross in the process.

There's a variety of species humans change too. Here's some of them:

  • A mix of giants and orcs
  • pallet swapped elves
  • Dragonkin
  • Pink skinned, majin boo look alikes
  • Humans with animal characteristics and devil like appearance.

The change is completely random.

Edit 2: This event is supposed to occur on modern day earth.

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    $\begingroup$ Which civilization? Despite what the critics of globalization say, there is not a single civilization on the whole planet $\endgroup$
    – L.Dutch
    May 29, 2021 at 7:13
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    $\begingroup$ Could you specify how monstrous these new humanoid species and how much destruction on which scale they can cause? Also, is the change random or not: Demographically, geographically, culturally, politically, etc.? Another important point is the speed of change. Do people change overnight or it takes some prolonged time (specify this time)? Do all 10% change at the same time or over some period of time (specify the period)? Please also provide information about the invaders and their capabilities. If they are cute harmless bunnies they won't change much. $\endgroup$
    – Otkin
    May 29, 2021 at 7:19
  • $\begingroup$ @L.Dutch All of them. The changes happens world wide. If there you think that some survive while others don't that's also a valid point to make. $\endgroup$ May 29, 2021 at 7:34
  • $\begingroup$ @Otkin Huh, forgot about rate change. To answer your question, the changes are random, all 10% change at the same time and their capability ranges from farmers and hunter gatherers to powerful enough warriors that would require a lot of preparation, bodies and luck to take down. $\endgroup$ May 29, 2021 at 7:40
  • $\begingroup$ Please edit your answer to include additional information. It is hard to sift through comments in search of details. $\endgroup$
    – Otkin
    May 29, 2021 at 7:42

4 Answers 4


The ancient Romans had the term decimated for the punishment of a military unit for cowardice. It means killing one in ten, e.g. for cowardice in battle. More recently, a military unit that suffered 10% fatalities would be due for rest and restoration, and the slow integration of replacements, if the military situation allowed it. There are plenty of examples where a regiment or division was kept in the line after such a toll, but leaders should realize that the unit was seriously hurt. Civilian society isn't under the same stresses as a combat unit, but as a whole it might also be less resilient.

But this assumes that the 10% affected individuals are effectively "lost" to society as we know it. As a writer or game designer, you have some flexibility here. Assume that a person well integrated into society becomes a Dragonkin. After the initial shock has worn off, will he or she go back to work? Will he or she love spouses and children less? Will they still be willing to live with the Dragonkin? I guess there will be a spike of divorce rates, but that doesn't wreck civilization.

On the other hand, the complete shock and chaos from fear might well wreck civilization. As the saying goes, a modern society is just three square meals away from anarchy.

Many people in Europe (I don't know the numbers from elsewhere) went into a voluntary lockdown when the Corona pandemic started, at least as effective as the mandatory lockdowns later on. There were sudden shortages of storable food and toilet paper, even in places where the supply chain was never closed. If this "transformation plague" strikes worldwide, in 24 hours, with no way to know if and when it will end, then there will be panic. People locking themselves up in their homes instead of going to work. Other people looting the supermarkets.


The major earth religions are fine with aliens.

The catholics are happy with them, muslims would be happy with them, and Hindus and Buddhists have enough aliens in their religious texts that they likely wouldn't have an inherent issue with them.

As such, people being transformed to aliens wouldn't be a big issue. So long as they were friendly and nice the majority of world religions would be fine with them.

The 1/100 insane people would cause massive casualties, but could be handled by most country's police. 3/1000 people are cops, and have access to some degree of military hardware. It would be chaotic, but they could murder most monsters with coordinated gunfire, especially with civilians handling a number of them. The new civilian monsters would help, since they outnumber the mindless 10-1. Military strength is not very useful without military coordination.

The invaders would collapse some societies, but not all.

Some countries are set up with extensive measures of gun control, demilitarization, and pacifism, since war is uncommon. Such countries, including many european countries, would fair poorly as random monster attacks and portals overwhelmed their scarce military resources. Those with fewer police, national guard, and civilians with guns would have severe issues as monsters rampaged. Some would survive, using cars, home made explosives, and local supplies to ward off monsters, but this would be a very difficult thing to survive.

You can cripple a tank with a gun by shooting out the optics, and you can cripple a fighter jet by shooting it so civilians with guns can to some degree handle powerful monsters. It's much harder to survive organized military monsters that use their troops well.

Other countries with more guns and more armed soldiers would do better. The USA, say, would probably do fine in most areas because there's lots of guns and lots of soldiers, except cities with extensive gun control which would be destroyed by ravaging monsters with military level abilities.

There would be short term disruption of a lot of countries, and then you'd see a new world order with Europe and some parts of Asia overwhelmed by monster waves, and the China and the USA as regional hegemons that maintained control and promised safety to their allies.

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    $\begingroup$ I think you may be underestimating the potential of European countries. Switzerland, for example, has more than enough guns per capita to absolutely annihilate a wave of monsters, while the others all have highly capable and organised militaries and disaster response plans (including, believe it or not, zombies) and would be thrust into a state of martial law (with conscription, if required) very quickly. Also: gun control is a plus if the monsters are capable of operating firearms... $\endgroup$
    – Joe Bloggs
    May 29, 2021 at 12:41
  • $\begingroup$ Switzerland has 8 million people who would do fairly well, but they'd face invasion on all sides by less successful nations, and the militaries of other countries haven't faired well in handling insurgencies and hit and run attacks elsewhere, and probably wouldn't do great at home. $\endgroup$
    – Nepene Nep
    May 29, 2021 at 12:42
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    $\begingroup$ I don’t think they would. 9 people can kill a monster with nothing but kitchen knives just as well as they can with handguns. Hell, knives might be safer because there’s less likelihood of collateral damage. As long as the majority of humans don’t immediately die (which is highly unlikely, given the ratios), even countries with strict gun control are more likely to see pitchfork-and-torch wielding mobs of humans than they are total collapse. And that’s without considering internal police or military response. $\endgroup$
    – Joe Bloggs
    May 29, 2021 at 12:49
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    $\begingroup$ No sane unarmed soldier is going to go into a 9v1 fight, and with good reason. Plus: only a portion of those aliens have power that puts them on par with the world’s military. Most of the aliens are just going to get slaughtered if it’s a straight fight, and the ones that won’t have to face off against the actual military and the rest of humanity, and since no modern standing military (including those in nations with gun control) could hope to survive if their own populace suddenly wanted them very dead (logistics and all): my money is still on humans, regardless of gun control. $\endgroup$
    – Joe Bloggs
    May 29, 2021 at 13:20
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    $\begingroup$ The only countries where lax gun control laws would make a difference would be those where the standing military can’t challenge those with the weapons: namely countries where the standing military is so unorganised as to be destroyed by the incursion anyway. $\endgroup$
    – Joe Bloggs
    May 29, 2021 at 13:35

(Very) temporary panic and chaos, but not anywhere near civilisation collapse

If the change were not random and affected the top-10% of the global population (the most powerful people on Earth) there would be a remote possibility of the collapse of the modern civilisation. However, when the change is random the collapse is not possible.

The history of the Black Death shows that regardless of the government's competence (some governments were terrible at handling the epidemic), types of response (there were a lot of bizarre types of responses), levels of organisation (some places lost most of their administration due to the epidemic and it took some time to find suitable people to replace them), and cultural differences (many different cultures were affected and they handled the epidemic differently) the civilisation will not collapse despite the high losses. It is estimated that 30% to 60% of the European population died in 1346–1353.

One can argue that the described change is sudden, more frightening, and affects more people simultaneously compared to the Black Death. This is true, but it does not mean that people will lose their minds and start behaving irrationally en masse. Human response to disasters is rarely panic, chaos, looting, or irrational fear. On the contrary, people display altruism, high levels of energy, and surprising levels of self-organisation. People tend to band together and work toward resolving the crisis. This happens in all human societies and all cultures.

The only cause for mass panic in your scenario would be mass media fueling panic. However, since the change is random and 10% of the population is affected all people will have personal experience with the disaster and its consequences. They will have no choice but to stay rational and think about ways to deal with their situation.

You can expect temporary chaos at all levels while people and governments assess the situation and come up with countermeasures. But it will not last long. Even if the central government is incompetent and cannot come up with a coherent plan of action, you will have local governments and organisations stepping in and dealing with problems.

You also need to consider this:

  • your newly created monsters are disoriented and disorganised unless their physical change also somehow changed their personalities and made them a part of a hive-mind, therefore, they are no match to humans who have police, army, self-defence forces, paramilitary, and all kinds of organisations with contingency plans and training;
  • physical ability to inflict damage is not the same as actual combat prowess, people must be psychologically ready to hurt and kill people in order to use their skills and abilities to the fullest extent (that is why 'good guys with guns subduing bad guys' is nothing more than a myth);
  • some percentage of these new monsters will commit suicide due to inability/lack of desire to deal with the consequences of change;
  • if new monsters retain their human personalities many of them will join the effort to subdue monsters that lost their sanity, thus, the human response will be stronger.

I would not be surprised if within a year most of the changed beings were hunted down and killed (most likely), locked in research facilities (2nd most likely scenario), or subdued in some other way. Once it is done things return to normal. In ten years no one will care about the mysterious change.

What if the changed people got reinforcements from a parallel dimension?

The outcome will depend on the invading forces and their preparations, plans, strategy, firepower, etc. Anything can happen, including the collapse of human civilisation.

P.S. I strongly disagree with the idea that countries with more guns per capita will weather this crisis better. I believe that countries with better organisation, better contingency plans, stronger governments, and higher public trust in their governments will fare better than countries with highly militarized population but weak and low-competence governments. The proposed change affects 10% of the population and requires an organised response.

  • $\begingroup$ Well, it actually depends on technicalities. A nice, well organised gov would face huge problems when those mutants are mixed bag, with huge share of them being possible to save, but big chunk requiring assisted living or even worse posses long time threat. On the other hand if they are on extremes - either not big deal or feral beasts - would be fine. A society that shoots / lynch on sight could avoid some problems with mixed bag mutants. $\endgroup$
    – Shadow1024
    May 31, 2021 at 8:46
  • $\begingroup$ @Shadow1024 The OP specifies that we are talking about the present-day Earth. The only country in the world that has more civilian held guns than people is the USA (120 guns per 100 people). The second most militarized nation in the world is the Falkland Islands with 62 guns per 100 people. Most other countries lag way-way behind. In the USA, gun ownership varies by state: from 8% of households in New Jersey to 66% in Montana. Moreover, almost half of all guns are held by a minuscule minority of gun owners (<5%). $\endgroup$
    – Otkin
    May 31, 2021 at 19:39
  • $\begingroup$ [cont.] There is no society on modern Earth (that I know of) that shoots/lynches on sight or capable of shooting on sight when talking about the civilian population. Military and law enforcement agencies need a law or some other order/directive from above to be able to shoot on sight. A strong, competent government is more likely to issue such a directive in case it is necessary since these governments historically act in a more decisive and timely manner. $\endgroup$
    – Otkin
    May 31, 2021 at 19:44

It Could Very Well Do It

Imagine you're one of these people. After a bad month where yougain a lot of weight, you transform into a devil. Within 24 hours. Maybe you go to bed normal, and wake up with cloven hooves. Maybe it creeps up on you painfully over the course of a day. You are going to FREAK OUT. You may very well think they're cursed by god almighty, even if ypu were a professed atheist. Things wouldn't be much better for people without knowledge of the judeo/christian view of the devil. Because there is ZERO scientific reason for what's happening to them. Or their loved one, or their coworker. They're going to freak out. Some may kill themselves. Or think the world is ending and do "whatever it is they do because the world is ending." Now imagine them somewhere apart from their home. On the highway, and suddenly their feet don't fit their shoes. Or were flying a passenger plane and suddenly their co-pilot starts screaming at them because they've developed horns. Or maybe two soldiers in Russa/US both realize they're turning into monsters. The psychological repercussions would be heinous.

Now imagine 1:10 of these people turn into mindless killers. Do they look different from the other 9? If they do, will anybody stop to think about it long enough to NOT treat the other 9 like the crazy one? At least for the first few days/weeks months? If they don't, how do you tell? Especially in those first crucial days? This isn't like COVID-19, where (at least in europe and the US) there was a steady stream of data coming towards you along with the main wave of the pandemic. It occurs over 24 hours, all over the world. There's no stopping it, and it's strikes at random. People are going to lose their minds. Command and control will break down. Sure the head of the CIA became a mindless killing machine of an ork, but the secretary of state turned into a literal devil (he claims, no fingerprint/photo match obviously so is it really him?) and says he still wants to do his job. Do you let him? What if it happens to a head of state (and it will, to 10% of them)?

And on top of that you have an invasion of people/monster/things that look just like Uncle Bert who turned into the devil and drove his car off a cliff. Or that woman who turned into a giant and slaughtered her way through Santa Monica. THEY are aggressive. Plus they're magic. Maybe they DIDN'T turn 10% of earth's population into monsters. maybe they REPLACED 10% of earth's population with monsters, and the one claiming to be Secretary of State is lying. The world will come apart at the seams for a few weeks, all at once, everywhere. When that happens the first world falls apart, along with most urban areas once the food/power/fuel systems get stretched to the breaking point. Because most of the world simply doesn't have enough to get by for weeks without the complex net of modern logistics. After that you get the standard "everything went to hell" scenario of your choice.

TL/DR: If everyone kept their heads and acted as rationally as possible, it would be ok. But people aren't like that, and things would go to hell in a handbasket.

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