A species genetically engineered/corrupted/bred for warfare is a staple of fantasy. Lord of the Rings' orcs and Wheel of Time's Trollocs come to mind, for example. Creatures created by the bad guys to conquer the world- but at the end of the day, how effective are these creatures in waging war?

If you were creating a species specifically designed to serve as soldiers in your medieval wars of conquest, what biological traits would improve their effectiveness? Would they be mammals, insectoids, reptiles or crustaceans? A way to control and replenish these creatures would also be required.

Note: I know the society of these creatures would have a very important role in their effectiveness as soldiers, but at the moment I am focusing on purely biological traits.

My appreciation and thanks to anyone that considers and answers this question- I look forward to seeing what you come up with.

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    $\begingroup$ Another great example: the Krogans in the Mass Effect universe. $\endgroup$
    – Joachim
    Commented Jan 14, 2022 at 14:26
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    $\begingroup$ Medieval wars...where? The steppe nomads had vastly different tactics and mode of warfare to western European armies due to the different factors in each location. $\endgroup$
    – VLAZ
    Commented Jan 14, 2022 at 15:00
  • $\begingroup$ IS this fantasy-tech, using magic instead of genetic engineering? I would go dual-function. Normally small and innocuous, but when appropriately stimulated, the transform like locusts, growing big as they eat everything, then sprout claws, horns, etc. $\endgroup$
    – DWKraus
    Commented Jan 14, 2022 at 15:11
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    $\begingroup$ I assume that these soldiers need to be humanoid and semi-sentient? Otherwise I would go for ant colonies designed to eat foodstuffs that are nearby X but avoid it nearby Y. The X is something of an army, like a certain amount of metal in the air and Y is something you put near your own food so it doesnt get eaten. If that doesnt work I would go for something like militant honey badgers, hippo's or Grizzly bears. As a herd animal under your control hippo's would be ludicrously dangerous, HoneyBadgers reproduce and are tough and Grizzlies are tough and dangerous. $\endgroup$
    – Demigan
    Commented Jan 14, 2022 at 18:48
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    $\begingroup$ What are you conquering? There are different requirements for different types of warfare. Soldiers that are effective in big battles in wide-open spaces are not as effective in a jungle or siege. Also, what are the goals of the conquest? Do you need to assimilate the population of the conquered territories or do you plan to wipe them out completely? $\endgroup$
    – Otkin
    Commented Jan 14, 2022 at 18:50

20 Answers 20


You're asking after biological traits, specifically?
In no particular order:

  • Rapid reproduction.
    Whether natural or artificial, you want to be able to quickly create individuals. A species that naturally procreates swiftly, with relatively short gestation, is preferable.

  • Naturally aggressive.
    Some species have an inborn tendency to react purposefully and violently to anything they might perceive as dangerous.

  • Survival instinct.
    You'll want your warmongering creatures to fight until their last breath, and to ideally have an overproduction of adrenaline for that extra edge.

  • Intelligent enough to use weaponry or other material.

  • Dumb enough to not question their nature/instinct/orders.
    You don't want philosophers or other stinking dissidents amongst their ranks.

  • Natural armour would be nice: scales, thick leathery skin, shells. Alternatively, spines or similarly deflective coverings. If not armour, than the species should be able to rely on speed and agility.

  • Last but not least: strength, endurance, and willpower would perfect these creatures. Strength and endurance are evident. Willpower is related to survival instinct and aggression, but pertains more to awareness, and a conscious choice to keep going.

I'm not sure if you're also already looking for something that meets these traits, but I'll be on the lookout.

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    $\begingroup$ "Naturally aggressive" needs to be tempered with something like a pack mentality or some other hierarchical instinct or they will be uncontrollable by their handlers. $\endgroup$ Commented Jan 14, 2022 at 18:28

Coordinated & Fearless.

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We know from the Roman period that coordination and tactics are far more important than physical attributes of a warrior. We also know that in general medieval battles end long before one army wipes out the other -- rather they end when the front line gets demoralized and flees.

Your soldier race is blindly obedient and hence very coordinated. On top of this they have excellent senses to listen to orders in the middle of a noisy battle. I suggest infra-sound as it attenuates less than the human range.

Hence you can easily call a platoon of 1000 back from the front and replace them with a fresh 1000 as the fight goes on. You can even do this without practice or rehearsing, so you are free to control your army like an RTS game rather than like shouting into a crowd of thousands of dying men.

They are also immune to morale and fight to the death if ordered. Hence If 100 of these guys go up against 10,000 mundane troops they often trigger a rout. The 100 guys don't have to fight all 10,000 at once. They only have to form a circle and then fight however many enemy soldiers fit along the length of the circle. All the while they are rotating their tired troops from the edge of the circle to rest on the inside.

Note to Self: Add a relax command to make the soldiers rest and catch their breath, even in the middle of a battle.

The carnage on the edge of the circle is enough to make the nearby mundane troops flee in terror. This triggers the rest of the enemy army, who cannot see what is going on -- and only see their comrades drop their weapons and run for their lives -- to flee with them.

On top of this I suggest the Roman method of short and/or thrusting weapons. This means you can have five of your soldiers armed with short weapons comfortable engage each enemy soldier wielding a long weapon. That turns the 100 vs 10,000 battle into 20 duels of 5 vs 1.

Then add all the normal extras like thick hide, bad smell, strong body, extra endurance, lower food requirement, fast healing, disease-resistant, redundant organs, natural weapons, scary face, poisonous blood, fast reflexes, endurance to heat and cold, fast breeding and growing, and short life span.

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    $\begingroup$ Downvote boo! Boo! $\endgroup$
    – Daron
    Commented Jan 16, 2022 at 19:36

If you just want melee fighters, I'd go with armored (like armadillos) 8-legged spider-like creatures. Not necessarily insects; but similar looking.

The legs end in a hard hoof, but that is like the heel of a hand; they have retractable opposing grasping digits there (like a cat's claws are retractable) that let them wield weaponry, climb, etc. These can be tipped with claws that can be used for fighting directly.

Like spiders, they can disconnect damaged legs and regrow new ones. The body part can carry weaponry. The eyes are arranged for 360 degree vision in the horizontal plane, and nearly that in the vertical plane. They have infrared and ultraviolet vision. You can't sneak up on them.

Hearing like a bat, with echo-location -- Echo location in a bat is so much like vision they can fly through a pitch-dark room with lengths of string hanging from the ceiling, and not touch any of them.

Pinpoint throwing accuracy of knives, rocks, grenades or anything else over a 100 yards are so. If a quarterback can do it, they can do it better.

They can stand and fight on any three legs, two in a pinch.

The can spew poison or disabling liquids, like skunks and bombardier beetles, perhaps lethal poison like snakes, many insects, and even plants.

They have reflexes as fast as the fastest animal on Earth, whatever that is. That lets them wield a shield or buckler (small shield) with extreme accuracy against arrows, spears, knives, or thrown rocks.

They are smart enough to don steel armor if needed.

Needless to say, extremely strong for their weight; I'm not sure which mammal holds the record, but like that.

Perhaps they have tough thick hair all over their bone armor like a lion's mane; the volume of it protects the lion's neck from bites. On this animal, it can cushion the blow of projectiles and such.

I would ground your genetic engineering in Earth reality and genetically proven evolved battle adaptations, for both offense (like predators) and defense (like prey).


I'm going to assume that you want a biped-capable humanoid form. With that said:

Modified Grizzly Bears.

If I have to choose between 10.000 Uruk Hai or 100 intelligent Grizzlies, I would choose Grizzlies. Especially with some armor and some redesigned weapons the Grizzlies would be closer to armored vehicles than infantry. Outside of magically enhanced fantasy creatures (say a regenerating Troll) I see little that can beat the Grizzly bear.


  • While not true for Grizzlies specifically, some bears can carry several cubs per litter. We'll go with the average of 2 to 3 cubs per litter for Grizzlies rather than modify it and risk health problems.
  • For some bears (again, not Grizzlies), the male bears will actively kill all cubs they come across that do not smell like they carry their DNA. If they succeed the mother bear will immediately be able to become pregnant again, allowing the male bear to get more cubs with his DNA. --> we'll modify the male bear to simply try to get any bear pregnant that does not nurse cubs of his own DNA. Female bears will be modified to be able to become pregnant as soon as the previous litter is out (and a small regeneration period has passed). This feature will last until a certain population density is reached or a certain food is given by their owners.
  • Grizzlies grow to maturity in about 8 to 10 years, far faster than you can grow and train humans. It might not be the "spawn them in a couple of days/weeks" like the Uruk Hai but if we allow such techniques for spawning then then I dont see a reason why the Grizzlies couldnt be spawned the same way.

Food and resources:

  • like most bears Grizzlies are omnivores, from grasses to nuts to roots to fish to meat etc. This makes them relatively easy to feed.
  • armies march on their stomach, a small army of Grizzlies even more. Fortunately your bears have a hack: hybernation. --> modify the Grizzlies to hibernate on command after reaching a minimum amount of food. They wake on a command (say a certain smell) or when their foodsupply is low. During hybernation the bear will even re-use a portion of their "waste". They also do not pee or poop during hybernation for several months.
  • Grizzlies are excellent foragers.


  • Grizzlies are essentially 300 to 700kg Honey badgers. Their thick fur and thick loose skin make them immensely tough. They can handle the biteforce and clawed punches of their own species with relatively low damage. Edged weapons like swords and axes have trouble piercing it when handled by humans, blunt weapons are almost useless and until rifles are introduced the Grizzly is pretty much only defeatable through manpower by impaling it with a bunch of spears. A better way would be to bring small siege weapons and hope you can kill them before they get into range.
  • Grizzlies are immesely strong, there are movies of a Grizzly flipping a 300+ kg garbage bin several times with ease. With some metal armor over the vitals they would be medieval tanks.


  • Grizzlies are well able to sneak up and ambush their enemies, including intelligent humans.
  • even unarmed a Grizzly can beat the most fit armored and armed soldier. If these Grizzlies go bipedal with weapons and armor (and quadruped when running). When running on all 4 paws they can reach almost 60km/h.
  • Grizzlies are excellent at climbing
  • Grizzlies are excellent at digging.


  • some modifications to intelligence are necessary to make them more useful. This does mean a larger head or less skull to protect the brains. Although Grizzlies are already fairly intelligent.
  • $\begingroup$ Like the Panserbjørn from Dark Materials, but with a different ursine base? Nice idea. $\endgroup$
    – Corey
    Commented Jan 17, 2022 at 5:37

Assuming you have some way to control them how about flying bullet ants. You release an army of them on the opposing humans and watch them scream in pain.

  • $\begingroup$ That's really more of a comment. Expand on the virtues of the ants. I'd say this is a frame-shift saying other non-intelligent organisms would be the best to evolve for war. $\endgroup$
    – DWKraus
    Commented Jan 14, 2022 at 15:07

Thank you SO much for asking. I've always wanted an army of soldiers to do my bidding, but never really thought about what they'd be like, but then you mentioned crustaceans and genetic mutation.

I'm now making an unstoppable army of crab soldiers. Small ones to slip in, damage equipment, and attack sleeping troops in their baaracks. Human sized ones to engage the enemy directly on the battlefield, and crabs as big as a modest home to deal with any obstacles that get in the way of my smaller crabby soldiers.

Hopefully, this will be enough. If not, I'll unleash tiny fast-breeding crabs into the trousers of opposing troops. If my victory doesn't come soon enough, megacrabs will smash the cities of my opponents.

The crab army is unstoppable. Surrender now or face their claws.


If you need a reason for an army that's worth the investment of all the genetic engineering, decades of housing and feeding, etcetera; start by considering the deficiencies of the alternative: a human army.


And where exactly humans fall short depends primarily on the specific circumstances of the war. Are all your peasants suffering from heat stroke when fighting the desert uprising? Then maybe make the dromedaries into your thralls. Are they clumsy on the seas? Engineer some mermen! We put our human soldiers in different outfits for different climates and expect them to function just as well, but that's only because humans are our only source of manpower. If we can create our own species, then there's no reason to do it only once. Have different armies for each terrain! Have mermaids in the seas, pumas on land, eaglefolk in the air, and as many other variations as you have the imagination to think up and the means to support.

Similarly, do you want your soldiers to be ugly and terrifying? Or rather sneaky and deceptive? We expect humans to play both the part of monster and spy; why not have different species specialised to do it?

Balance of power

But maybe do not make them too good. More empires have been overthrown by their own uppity generals than have ever been conquered from the outside; a government and a monarch have the official monopoly on violence, but that only holds when they actually control all it.

That means that you must keep your new breed of super-soldiers from usurping you. There's generally two approaches;

  • Make them deficient in some way to their human counterparts. For example, limit their intelligence to sub-human levels. Go for numbers instead. Maybe take inspiration from a fast-breeding species like insects for that approach.

    You can also make them unable to breed on their own. That requires you to produce every generation from anew, but it makes them fundamentally dependent on you. It also solves the issue of having the army be a constant tax on your finances during extended peacetime - just let them die when you don't need them.

  • The other is to treat them as citizens. Release them into your civilisation when you are done; let them have families, grow rich, live their own lives. The advantage is that your army will feed and support itself; the downside is that they are reduced in effectiveness because they expect pay, and to return to their farms and houses when all is said and done.

Those considerations mean that your species cannot just become superior to humanity in every single way. There's always a cost.


Finally, many details about the species end up being less important than they might seem. When you have the magic or tech to engineer both insects and crustaceans into your very capable pawns, then their biological differences start to matter less as you adapt them to your template of a soldier. Will a camel still only need a thimbleful of water daily, after you have engineered him to be bipedal, fast as a leopard and strong as a gorilla? No way to tell until you zone in on a specific creature, but I think that the differences start to blend away the more you meld the base species to your liking.

That also means that there is much room for creativity for you as the author of the story, or for the evil lord as the author of the species. Maybe a freak accident left the wizard with a mechanical claw for a hand, and that's why he prefers crabs? If he can make the crabs giant and obedient, then maybe there's no more reason not to pick that species. You can have your type of soldiers not just be 'optimal', but make their appearance serve the plot too!


The Dogs of War:

I am assuming that you are talking fantasy-tech, where it's basically medieval with magical "high" tech engineering. So my logic is based on such a setting. You can argue the competitive advantages of various designs ALL DAY, and every species needs to adapt to the specific conditions they encounter. I think most war races are impractical, since they would inevitably burn themselves out of usefulness unless they were in small numbers and thus of limited usefulness. They would perpetually be a potential threat to whatever species created them.

So I propose that the biggest hurdle for such a species is that wars end and a warrior society must constantly be fed resources it cannot produce on it's own. They must follow one of two main paths. They must enslave the societies around them and be perpetual conquerors/rulers, or they must have a relatively harmless function in society when there isn't a war to minimize their impact.

  • Rulers: A society that conquers others must fundamentally be compatible with those they conquer if they are dependent of those conquered for survival. This means they would need to be social, able to be peaceable with them, and regulate their consumption carefully to prevent them from destroying the systems they need to survive (eating or starving all the peasants). 99% of the time they would be sitting around on guard duty or patrols, not fighting. They need to be competent governors and be in charge since inevitably a non-soldier ruler at some point will come to fear or resent their soldiers consuming vast resources and contributing nothing. So these rulers are likely to be augmented humans or a similar species that can relate to the species ruled well and function in their cultures.

Most species are unwilling to create species that will enslave them, so this isn't ideal. But a war-race might be created to win the war without regards to the consequences.

  • Pets: At the other extreme, I would suggest a military species that degenerates into something small and harmless when there are no wars. I imagine dogs where the females are relatively unintelligent breeders, and the males are like tiny lap dogs - usually. The dogs are treated well and kept as adored pets. When war breaks out, they are induced (somehow) like locusts to transform into warriors of rapidly growing size and intelligence. Loyalty is due to genetics and them being raised by and dependent on the master-species (assumedly humans). In non-war times, a handful are kept as warriors/guards and these would be the reproductive males. The females don't go to war, and as long as a handful of males are available, they can be regenerated by the master species as needed. Warriors left after war are relatively short-lived to minimize long-term drains on resources.

The traits that you would require for a genetically/magically engineered soldier are the most important factor, from which you could then design the ideal creature. In fact, the origin of such a creature is of little importance, so long as it has or can be given the required traits.

So, the traits required would be:

  1. Selective: This creature must be able to tell friend from foe, and be able to distinguish between individuals.

  2. Loyal: The creature must accept orders from those in its chain of command, and must not accept orders from other persons.

  3. Intelligent: The creature should be able to interpret its orders intelligently, be able to improvise around its orders and goals, and know when its orders cannot be carried out. It should have a good memory for details.

  4. Fast: The creature should have the quickest possible reaction time, minimizing the duration of their observation-decision-reaction loop. Preferably it should be able to out-react a human by a very considerable margin. It should also be able to move quickly.

  5. Self-sacrificing: The creature should be willing to sacrifice its life if necessary to carry out its orders, but should do so only if such self-sacrifice was likely to lead to the successful execution of its orders.

  6. Perceptive: The creature should have good senses so as to be better able to foil ambushes or locate hidden objectives.

  7. Stealthy: The creature should be able to hide and sneak effectively in multiple environments. Being able to pass for human would be a great advantage. Being able to be easily underestimated based on its appearance would also be advantageous.

  8. Easily replaced: These creatures should be able to be produced in large numbers and become an effective fighting unit in as short a time as possible, with a minimum of training and a minimal growth time. Being produced with built-in skills and knowledge is highly desirable.

  9. Tough: The creature should be robust and difficult to injure, highly able to continue functioning while injured, and should heal quickly. It should not be afraid of pain, and should be able to act despite its injuries when necessary.

  10. Storeable: These creatures may not always be needed, so they should be able to be ordered to enter a state similar to hibernation or torpor in which they consume a minimum of energy and resources. They should be able to be roused from this state at short notice.

  11. Unambitious: The creature should act for the good of its society, not for its own benefit. It should have no desires or expectations for itself or its offspring (if capable of reproducing at all) beyond its loyalty to its society and its orders.

  12. Strong: Being physically capable increases both the combat and non-combat utility of the creature. It need not be physically particularly large in order to be strong. It should be physically strong enough to overpower the strongest humans.

  13. Self-sufficient: These creatures should become useful after their birth/creation with a minimum of other resources, and the resources required should be as commonly available as possible. The resources required to produce them should be similarly simple and common.

  14. Dangerous: Having a variety of natural weapons built into its body would mean that these creatures could not easily be disarmed. Toxins should be available to it,including soporific, paralytic and lethal options. It should also be able to employ manufactured weapons, operate crew-served weapons and make use of any available human transport.

  15. Mobile: Being able to swim, run and fly well would be highly advantageous.

So... what sort of creature would meet all these requirements?

I'd personally go with something that was a chimera of a human and an insect. At first glance, it'd appear to be an average-sized, harmless-looking pretty young woman in a hooded cloak, capable of interacting with humans in a civil and civilised manner. However, beneath the cloak - which is part of its body - would be four arms, four dragonfly-like wings and an apparently armoured body and limbs that is actually its armoured exoskeleton. It would be able to extend sharp, toxic appendages with which it could fight, or could use human weapons with greater skill, strength and speed than any human.

Despite their appearance, these creatures would be sexless, and incapable of reproducing themselves. Their only genetic imperatives would be loyalty to their society, and as they are non-reproducing soldier-caste types, that could include self-sacrifice. It'd have all the traits enumerated above.

These creatures would be produced by a breeder caste, which would be kept and protected by the human society that makes use of them. There would be numerous members of each gender of these breeders so that they wouldn't be vulnerable to having a single 'queen' breeder assassinated. The soldiers would be hatched from eggs, would grow rapidly before pupating, and would be fully capable after metamorphosis into their final form. The mothers would be educated as they matured, and would pass their skills and knowledge to their offspring - both breeder and soldier - after they became old enough to be breeders.

Soldiers would be able to be born and mature enough to be fully capable combatants within a year. A single pair of male and female breeders would be able to produce thousands of eggs per year. A major limiting factor to their reproduction would be supplying the necessary food. However, given that the soldiers can hibernate, they can be produced ahead of time and stored at a minimal cost, waking periodically for nutrition before returning to hibernation.

  • $\begingroup$ Looking at this list I actually think the OP is going about this wrong. Many of these traits are essentially mutually exclusive. A dangerous, tough and stealthy animal (for humans) must be complex, and the more complex the creature the harder it gets to reproduce and heal fast. Its one of my pet peeves for supersoldiers who are ludicrously complex but still able to heal in hours to days what should take months. So you would need some kind of weight system to signal which traits are superior to the one's they negate. $\endgroup$
    – Demigan
    Commented Jan 15, 2022 at 14:19
  • $\begingroup$ @Demigan My list is more or less in priority order. Additionally, by transmitting skills and knowledge from mother to soldier, we don't need to slow growth in order to achieve social maturity. A soldier could be mature within a year or less since it already knows everything that its mother took a decade or more to learn. Many large mammals are mature within a year or less, so it's not impossible. $\endgroup$
    – Monty Wild
    Commented Jan 15, 2022 at 14:24
  • $\begingroup$ I've been thinking, your "reproduction" comes before tough and strong. That means you would go for a Zergling style army. But would that not be worse in many cases? For example with equal resources if two countries start a fight then the country who focussed its resources on maintaining a tough and strong army would win the initial engagements against the faster reproducing but less complex creatures its facing. You'd need to use different stages perhaps: a pupal stage where they grow quickly and can be put to use quickly, an adult stage where they get strong and tough for the best of both. $\endgroup$
    – Demigan
    Commented Jan 17, 2022 at 16:51

I have a slight addition to what others have suggested here, because I believe there are two main issues that need to be resolved:

  1. As you raise the species members' intelligence, aggressiveness, and combat ability, the potential for them to go rogue grows exponentially. You might up with an army of super soldiers, but there's no telling that even a small number won't turn on you or your people.
  2. Militaries require hierarchies, which rely on a difference in power or strength. This is especially true if the species which is acting as the commanders of another species is weaker (imagine a human being assigned to monitor a squadron of 9 foot genius mutants designed to kill humans).

To solve this, the species that you rely on as an army could be a Bee-like Species, in that it has a dictatorial Queen with superior abilities, the majority of the species is biologically job-specific, and they have undying loyalty to the Queen or her successors.

Rather than trying to control the hierarchy of power at every level (assigning squadron leaders and so on), it is far easier to have a "Queen" of sorts that you keep happy, who in turn can naturally guide her mindless drones to attack your enemies. The Queen's superior intelligence means that she acts as a "translator" between you and the army you wish to use.

I purposefully left the method that you make the Queen "happy" blank because it could range from providing her with apples to paying large sums of gold. This means that there is a tradeoff between this idea and some of the others: While you don't have to worry about controlling each individual soldier, you now have to make sure you keep the "mercenary leader" satisfied.


This species would need to be physically strong, fit with enhanced health and immune system and also they would need to have far denser bones than the ordinary person. And also their regenerstion skills should be superhuman like Logan from X Men.

Also genetic engineering on the brain would be needed bevause your soldier species would need to kill a lot being very cold without feeling remorse like a serial killer do.


I think the closest living being to a permanent warfare species are viruses (though I know it's still debated if viruses fit the description of life): while wolves or lions, just to cite an example, will not hunt unless they are hungry, a virus will pursue infecting available cells and hack them into producing copies of the virus, without stopping until either defeated by the host's immune system or by the host's death.


Loyalty and Logistics

If your creature isn’t loyal and able to tell friend from foe; you’ve created a future enemy.

If the creature requires an inordinate amount of resources to survive, you’ve made something that won’t be cost effective and given you have a medieval society you can’t sustain things that require heavy and continuous resource investment.

Therefore you need a creature to be fundamentally loyal to its creator (imprinting, pheromones etc) and able to subsist on easily foraged resources. For instance it would be better for your warrior species to have a very broad diet as an omnivore, preferably one that can eat very common plants and insects to survive


You definitely do not want a biped: any of the joints in either leg become a weak point that cripple them. So, six or eight legs. As a bonus, they can be their own pack mules.

Then, they should have tough but fairly light shells, not so heavy they can’t swim. They should be able to fight with their claws, with their heads protected, or also hold tools, missile weapons or spears (particularly against cavalry). Of they need to reach up, they should be able to rear up on their hind legs. Open with a high-speed spear or saber charge, then skirmish. And some fast-acting poison would be just the icing on the cake.

So, I think you want something like a crab or perhaps a scorpion. It doesn’t need to be too large—it might want to avoid being too easy to bring an axe down on, but having to attack the lower body or the horse someone is riding while being hard to reach is an overall advantage.


Aside from the traits mentioned in other people’s answers, I would also recommend some sort of built in natural weapons, such as extremely sharp claws, spikes, or bladed appendages. Maybe a spiked tail like some sorts of dinosaurs/dragons. Actually, maybe some form of dragons or dragon-like creature would be pretty close to the perfect war creature.

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    $\begingroup$ Think Grendel of Beowulf… $\endgroup$
    – Kal Madda
    Commented Jan 15, 2022 at 22:16

Intelligent people are loyal for a passion or sentiment

If you create your perfect warrior race/species such as that described in your answer, then some day it may not remains under your control. If they are intelligent, dangerous and self-sufficient, then they will think more of their own benefit than yours and forget loyalty.

To sacrifice one's own life by an intelligent being needs a very strong passion or sentiment. In humans, it is country, king, religion, freedom etc. What is the passion or sentiment for your race. Money is an attraction for mercenaries, but then they are not very brave. People with a passion are always more brave.

Your warrior race/species should be either very dumb (not intelligent and passionless) or must have a strong passion. Otherwise they will become something like Gunslinger in 1973 movie Westworld.

What if the enemy also develops similar race

If enemy or many other nations also develop similar races then the whole world will be a big battlefield with almost never ending wars or until all the resources are depleted. This could cause a great damage to people and resources.


Creatures created by the bad guys to conquer the world- but at the end of the day, how effective are these creatures in waging war?

Now that's an interesting question.

In many cases - including the ones you mentioned - the answer is: just effective enough. What they lack in perfect suitability they make up for in numbers and savagery. With enough orcs or trollocs - and they have many of them - any force of conventional fighters can be overwhelmed. At least until someone brings sufficient force to bear - as Amalisa Jagad did in the WoT TV series - to eliminate sufficient of the enemies to swing the tide of battle.

If you were creating a species specifically designed to serve as soldiers in your medieval wars of conquest, what biological traits would improve their effectiveness?

The rest of the answers are heavy on details for this, but let me give you a slightly less... moral answer than most.

Were I to build an army to rival the forces of Man, Elf and Dwarf, I'd be focused on the following points:

  • Durable
  • Vicious
  • Capable (fast and strong)
  • Plentiful
  • Fanatical

I'd start with the nastiest, toughest critter I can find. Something like the Honey Badger perhaps, or mongoose. Using vile magics I'd twist the base stock into a larger, more upright form while increasing the potency of their existing features: coarser, denser hair for protection, denser bones and muscles, sharper claws and teeth. As part of the process the brains would be modified to increase their native intelligence and their neurochemistry altered to break down if not supplied with particular chemicals - which we'll revisit later.

That covers the first few points. Now for the last two...

Once the desired state is achieved in a few individuals I'd have them disassembled at the smallest possible level - individual cells by preference - and use the parts as 'seeds' in a huge ritual, feeding living (or near-living) beings to the ritual to create hundreds of thousands of troops. Of course the process would corrupt some percentage of the resulting units, but as long as we get a reasonable success rate we're golden. We'll keep a couple of the best examples around for the next round of creations.

And finally, the fanaticism. This one is pretty easy in comparison to the process of creating the troops in the first place. During the creation ritual a powerful set of compulsions will be overlaid on the minds of the 'clone' troops, forcing them to follow the orders of my commanders while subverting their desires to protect themselves. If we left any of their instincts intact then we'll hook into whatever protection instincts they have left - probably the instinctual protection of their own young that most species have.

And that chemical they're addicted to? Adrenal stearate. Given just enough - in tiny doses - it stabilizes their neurochemistry. But when dosed with it at the start of battle it turns them into berserkers, super-charging their aggressiveness and combat ability. I'll let you investigate how a supply of adrenal stearate could be acquired.


As a species, they should hot blood as it allows for better operationality. One may say that I am lacking Imagination, but I would pick human and modify them.

Why human? Physically They are good all rounded, can adapt to environment and have extreme endurance.

They also are outstanding in terms of intelligence and decision-making plus are naturally social and are exceptional for group cooperation.

In terms of reproduction human are slow to growth but nevertheless you can make billions of them in a century. Humanity went from 1 billions in 1927 to almost 8 billions now.

What I would change ?

I have to say that in my opinion all the following is unethical and that I do not endorse it.

First slight tweaking physically with genetic engineering not much but better senses (smell vision hearing), no more cramp, better physics overall, reflexe strength.

Better immune and digestive system.

Also you may want to increase the proportion of sociopathic people in this population as they can have normal social relationship but have less emotion and experience regrets differently.

It might be tempting to make super soldier, but you want an army not special forces. Keep In mind that you will need to feed them and that logistic is a limiting factor, so I won't increase physics and size yo much because of this.

Better food absorption and starvation resistance genes.

Selective breeding in addition.

If you can also increase the loyalty and stubbornness. Do not reduce pain, as it is important for self-preservation.

Education and culture are essential here: You want to make fanatics dedicated to your cause. But they have to be soldier, adapt to the battlefield, have competent officer. So, a solution is to organize them in an all militaristic society where service and death for the creator war is paramount honor. With indoctrination and training from childhood and selection of the smarter/strongest/wisest for NCO and officer.

Furthermore, an army need a multiple of role, by not making clone and letting them as a society select and organize they will the pick the best individuals for the job.

Lastly, Individuals that are deemed unworthy of service can always be use as worker.

  • Either fast reproduction or regeneration. They accomplish the same effect of keeping your army full after a battle, but the regeneration make it so that your soldiers don't die often rather that replacing them with fresh troops. Personally I would go with regeneration since battle-hardened veterans are better than new troops and you get them in a few weeks rather than years to grow and train new recruits. Both would be too much to handle.

  • Superior immune system and hygiene. More soldier die from diseases and infections than from the actual battles. Diseases spread like crazy when there are lots of people in close contact and in less than optimal health standards (aka an army). You want to minimize your overall losses.

  • Cost effectiveness. If you have a supersoldier that can defeat 20x more enemies than your regular troops, but he also eat for 30 regular troops, you are better off with your regulars. In an army, supply is king, you need that each new mouth is worth the supplies that it will consume (food, equipment, etc).

  • Iron nerves. Few battles are fight to the last man standing, or even until one of the sides can no longer turn the battle around. Most battle end because they got demoralized and routed, with few actual dead in relative terms. The victory should not come at any cost though, that's a pyrrhic victory. Sometimes its better to cut your losses, even if you are winning.

  • Social Cohesion. You have to much external conflicts already, the last thing you want is for your armies to start fighting each other. Social cohesion is a good indicator of internal stability and cooperation. This specie should instinctively have a strong group bond with the whole specie. Naturally evolved races wouldn't have it since their history would be full of internal conflicts due to competition.

  • Obedience and discipline. You want soldiers, not warriors. This is a big difference: warriors do best in small conflicts were individual skill can turn the tide, but a soldiers, while it may be weaker on its own, will fight in a formation where everyone support each other and follow the orders of its commander without questioning. In a way, both have its uses, warriors make better body guards for instance, but overall you want soldiers for warfare as they will.

Notice that intelligence is optional, you can either have than be intelligent like goblins, orcs, etc... or go with a war beast approach, where they are essentially the darklord warhounds. You can also have multiple races or a single race with polymorphism to specialize in determined roles, I listed the characteristics you want in the soldiers, but you will also need officers, generals, supply managers, etc... I also assume you can enslave your enemies to take care of the work that its not war.

Now for which animal group would be better, this entirely depend on what you want and will allow in your world.

Mammals are bad at fast reproduction and regeneration, but the will not be crippled by cold weather.

Avians are similar, but better at reproduction.

Reptiles are also bed a reproduction, but better at regeneration.

Amphibians can do both reproduction and regeneration very well.

Arthropods are good at reproduction and come with some build-in armour, plus they have proven to be able to do social cohesion and iron nerves. Not sure about regeneration, but structurally they can't reach human-ish sizes due to respiratory constrains.

All things consider, quantity always beat quality if the mass do not flee when they see the first few hordes being slaughtered. And, since small means cheap, technically an army of wasps with lethal venom or rats with thine poison spears would be the ultimate fighting force. Silly, but dangerous nonetheless.


At the end of the day, those creatures are as effective in waging war - or any other task - as their creator writes them to be.

For an obvious, recent example consider the various species/tribes/hordes in Game of Thrones.

Long before, consider the different effectiveness of Alexander's few Greeks against the uncountable Persian hordes? Consider how history suggests a few hundred Romans wiped out prolly 80,000 Britons.

When you have an idea for a story, write it. Question anything only when he wheels actually fall off… preferably not even when your wagons merely get bogged down.

Please remember, what you take in your stride, most readers will happily take in theirs, while what you merely stumble on, they will sprawl over.

  • $\begingroup$ While this is a good Writing answer, it's a bit less good as a Worldbuilding answer. I'm not going to downvote you for it, just pointing out the weakness. $\endgroup$
    – Corey
    Commented Jan 17, 2022 at 5:42
  • $\begingroup$ @Corey Thanks and what are you suggesting? Have I been mistaken over the several years I've thought Worldbuilding had, broadly, three objectives? Those were stories for their own sake; backgrounds for gaming; ways of filling time, often at the cost of other Members' imagination… Where have I been going wrong? $\endgroup$ Commented Jan 20, 2022 at 21:27
  • $\begingroup$ Don't get me wrong, your advice is good. I'm just pointing out that it's more relevant to writing rather than Worldbuilding. Answers here should be focused on the meat of the question, even when issuing a frame challenge. Worldbuilding is about systems, events and elements of worlds that people are having problems with. Check the help here and here for the intent, which may be other to how you've seen people using it. ¯\_(ツ)_/¯ $\endgroup$
    – Corey
    Commented Jan 20, 2022 at 23:41
  • $\begingroup$ I'm also not saying that you shouldn't give this advice as part of an answer... just that the answer should address the question in some way. $\endgroup$
    – Corey
    Commented Jan 20, 2022 at 23:58
  • $\begingroup$ @Corey Thanks and again, have I been mistaken over the several years I've thought Worldbuilding had, broadly, three objectives? Those were stories for their own sake; backgrounds for gaming; ways of filling time, often at the cost of other Members' imagination… Again, where have I been going wrong? What other objectives do you see? $\endgroup$ Commented Jan 30, 2022 at 20:59

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