How could an ancient army go about defeating a giant army of monsters? [closed]

Question

I've been trying to study military victories against the odds but a lot of the stuff doesn't apply it seems. The armies in those battles are usually not outnumbered as severely and when they are, they're eventually defeated anyways. Like the Alamo or Thermopylae. Or they exploit some weakness that my creatures don't have, like horse's fear of camels in Thymbra or overconfidence in Okehazama.

In my world, there is a giant monster army (think zombies but angrier and more fragile) coming to annihilate humankind. However, a last stand at a certain point manages to route them. Among their ranks are also 400 giant creatures, functionally similar to elephants.

The small monsters don't eat or sleep but are much weaker and more fragile than humans. Most are unarmed but some have primitive clubs. Any person with a weapon could kill them.

The Monsters have an army of about 2,000,000 and the humans number around 10,000 infantry, 7,000 heavy Cavalry, 6,000 archers + 6,000 horse archer allies that come later in the battle. The monsters have a hivemind but very little discipline and cohesion whereas the humans are led by a brilliant general and are highly trained and disciplined.

Think Roman infantry combined with Sasanian cavalry & Cretan Archers backed up by the Huns vs 2 million zombies that don't come back to life.

So what I'm asking is, how would a brilliant general use tactics & stuff to defeat an army like this?

Many thanks friends!!

Answer 1

Should be doable. Limit their effectiveness by using a choke point so they can only fight on a small front then slaughter them.

Your examples are not good ones, they were against trained experienced armies. The Spartans at Thermopylae and their Greek Allies could have slaughtered this monster horde. They weren't beaten by numbers, they were beaten by tactics and ranged weapons.

Basically any committed phalanx of experienced warriors at a good chokepoint would do it. Cavalry should be dismounted or kept in reserve and ranged units concentrate on the large foes.

If you wanted it even easier then prepare the ground beforehand with traps, pits and oil to be set on fire. These things are stupid, so use that against them.

And what's a phalanx without slingers? As a slinger I can throw a stone every 4 seconds. Taking my time at 10 seconds standing behind that phalanx I could wreak havoc on those monsters without tiring particularly. Archers are of lesser value as their ammo is finite. No need for accuracy they're coming as a big bunch and 1000 slingers would leave a huge pile of dead and maimed monsters 50 metres to 200 metres in front of the phalanx

Getting tired isn't a problem, at any one time at Thermopylae only 1/4 or less of the Spartan led forces were actually engaged with the enemy. Periodically they swapped with another 1/4.

Answer 2

Human can only fight for so long before he has to rest. This mean, IMHO, there is no way your army can defeat the horde of this size in a head on combat. They will get exhausted long before they can cut through this huge enemy army.

To ilustrate how much 2mln is, consider this - standing in ordinary military order for medieval infantry, a single trooper occupy between 0,5x0,5m to 1x1m. As your zombies are disorganized, I would assume the larger number. Then, assuming they stand in ordinary military formation, say 10 men deep, their battle line would stretch 200km! If they form massive block 1000 deep, they still stretch 2km.

Your battle line would be about 3 km long (infantry about 800-1000m @10 deep, cavalry say 70 units of 100 man each in wedge/column formation about 2km (wedge widest point 13 men, that would be some 20m wide for well trained troops and you need spaces between units, so 30m per wedge)). Archers would be initially in front of the formation then they need to move behind infantry and to the wings. Once melee starts, they will reinforce any hole that will appear in heavy infantry line. Horse archers should be faaar in front, firing arrows from the closest possible distance (as enemy has only clubs, that could be 10-15m) and kill as many as possible. Later when their arrow supply is exhausted, you move them to the wings of cavalry and extend the line.

Still I would consider there are too much enemy troops. 6000 horse archers would have about 40 arrows each, and could kill, say, 15 enemies each (as they have no defence and are fragile)? Normal archers would have to fire from longer range or over own infantry and usually carry less arrows, so I'd give them 5 kills per man. So, before arrows are expanded you would eliminate about 120k zombies. That's barely a dent in enemy formation. Then heavy horse would charge, and assuming they can just trample over enemy, break through, turn and strike again... I would say 2-3 kills/charge/man and MAYBE 10 charges in a day long battle that would be some 200k. So, I would expect your army can eliminate some 500k AT BEST before they are overwhelmed and destroyed. And that do not count massive monsters that can either be used early to disrupt your formation, break cavalry charges etc. or kept back and unleashed as your men are tired. If those are used effectively... You would be lucky to kill 200k.

So I would consider cutting the numbers of the enemy to 200 000. That is still impossible victory especially with big monsters on their side, but probably can be achieved. Especially if you have a lot of arrows for horse archers and can harass those zombies for longer time (days, weeks if possible).

Answer 3

Trickery

As @Archelaos has stated, there's a limit to how long a person can fight. Just as important, there is Murphy's Law, which is really the engineering principle that "eventually anything that can go wrong will go wrong". Even if the general can select terrain that will ensure a manageable frontage, sooner or later each soldier will make a mistake and die, and it's likely to be well before they have killed their allotted 200 enemies.

This means that any conventional military engagements will be solely for the purpose of supporting a totally non-military strategy. Let's run down a few options:

1. Trapped ground - this is very effective against stupid enemies, but without years to prepare there is unlikely to be enough manpower to prepare traps to destroy even 1% of the horde, let alone the 99% that need to be destroyed before even considering conventional warfare. Maybe they can draft lots of civilians to help with building traps, then send them to the rear before the enemy arrive. This is problematic though, as unlike the monsters the humans do need to eat which makes supply lots of them a task as difficult as mass producing millions of traps.
2. Fratricide - no information is given on the enemy command structure, but if enemy formations can be induced to fight each other by bribing or tricking their leaders then this is a very efficient tactic. As a second choice, bribe or trick the leaders into turning their portion of the army around and going home to seize power by making them believe an opportunity has opened up, as happened with the Mongols when Ogedei Khan died.
3. Burn them - while the terrain is not specified, if there is a sufficiently dry grassland or forest that the army will have to pass through then set fire to it as soon as they are in. Use as much of the cavalry and horse archer forces as required to ignite multiple points on the upwind side and let it burn through the monster army. Use as much preparation time as is available damming or diverting water from passing through this area, even temporarily. Wait until is has cooled down and the smoke has cleared, then send sorties in to mop up any survivors that managed to survive the flames. Note that the monsters' big advantage here is that they do not need to breathe and therefore will only suffer from burning, not smoke inhalation. However the monsters' big disadvantage is that they are probably too stupid to take intelligent action to protect themselves from the oncoming flames (eg lighting escape fires to burn a clear patch of ground they can shelter in while the fire passes by).

Answer 4

Easily, if they have the supplies.

Horse archers are generally fairly well trained, and a massive mob is an easy target. A typical horse archer would carry around 30 arrows, and so by going close to the enemy, launching 30 careful shots, and retreating, they could wreck the army in six runs. Even if you're pain resisant, an arrow rammed through your chest will make moving hard, and infantry easily able to mop you up.

The heavy cavalry can get in on this game as well. They frequently carried darts or spears to disrupt enemy charges, and could dart in and out to harry the enemy.

2 million zombies is enough to overwhelm any careful positioning or tactical battle plan.

The normal suggested number is that a well fortified group can hold up against ten times their number.

That many zombies could mob any soldier or trap or fortification. They could afford to make a bridge of bodies to charge up a wall, and Roman forts were not as solid as medieval ones. They could exhaust any opposing foe through sheer numbers, and make retreat impossible with an endless stream of fresh zombies to charge and attack.

But without range and speed, they're easy to defeat by horse bound people.

Answer 5

The key thing in this is considerations of the strengths and weaknesses of both combatants. Are the monsters really big and powerful, but awfully slow? Are the humans exhausted from a long march, or from bad weather? Maybe this happened to the monsters instead?

War is full of things going wrong. The most well conceived plans usually fall apart do to unforeseen things like the weather, the enemy changing plans, the enemy planting false information, delays in supply lines, etc.

If you want to come up with reasons for the humans to win, quite simply, your monsters need weaknesses - and every army will have weaknesses. Saruman's uru-kai army in Lord of the Rings looks very impressive, but controlling them and such would be extremely complicated.

Lack of direction in a battle could be a potential factor. One of the biggest revolutions in warfare has been efficient communication. Being able to immediately tell your officers where to go via radio is a massive help. In the past then, breaking up the line of communication in an army can lead to disaster.

There are a great deal of things to do with this. I don't have much else to recommend, other than researching the history of warfare, and perhaps looking at Sanderson's Laws of Magic, for how to give good limitations to your monsters.

Answer 6

Pikes, armor and fieldworks (but mostly pikes)

Pike-like weapons were well known in the ancient world (https://en.wikipedia.org/wiki/Sarissa) and they are likely to be extremely effective against unarmed monsters.

There is a recent blog by a historian discussing a similar issue (starts at "Q: Adam Haun asks: Zombie Apocalypse!")

The key quote is probably (emphasis mine):

Spanish military performance in the conquest of the Aztecs and the Inca demonstrate what happens when close-order heavy infantry are engaged by far, far larger numbers of enemies whose weapons have at best limited effectiveness against armor. By way of example, at the Battle of Vilcaconga in 1533, an Inca force of several thousand caught an ambushed a Spanish force of 300, on favorable terrain (a hillside where the Inca had the high ground), with the element of surprise, against an exhausted foe (the Spanish had marched all day)…and still lost (to be clear, it wasn’t guns that won that battle, but swords and pikes). The Inca took some 800 killed-in-action to the Spanish five. And those were clever, careful-planning, intelligent Inca, not mindless zombies;

The image there shows why pikes (or other long polearms) work so well - several rows of men can hurt the attackes with sharp things while the attackes cannot hurt them:

(by F. Mitchell, Department of History, United States Military Academy)

Even light armor - widely available in the ancient word - is likely to offer substantial protection against the zombies (from the same source):

And herein we have the zombie-lethality-problem: a zombie, even a fast one, is not actually a very lethal opponent. Zombies attack with fists, finger-nails and teeth and you only get new zombies when bites actually penetrate. But biting through even fairly thin fabric is extremely difficult! ... Even thick clothing – much less modern riot armor or combat armor – is likely to be extremely resistant to zombie attack unless the wearer can be pulled down and held down. The thing is, a dense mass of heavy infantry – be it modern soldiers with rifles and bayonets (a thing we still issue to troops, by the by) or just men with spears – is effectively immune to such mobbing tactics.

So using terrain, their armor and field works (e.g. dig a ditch, then another one) to their advantage a well-organized ancient army with pikes can plausibly achieve over 1000:1 kill ratio against the zombies.

Nothing crazy/advanced is needed, find a battlefield where you can't be easily encircled with a favorable slope, build a series of defenses (ditch/palisade) in depth so that you can slowly give up ground and regroup if things go wrong. At some point the attackers will also be slowed down by the mass of their dead bodies in front of your soldiers. Once again, you can use that to your advantage.

The presence of the large beasts complicates things a bit, but using the same source, we know that Romans already developed very effective anti-elephant tactics (mostly based on javelins), to the point that war elephants turned out not to be a very useful weapon in the ancient mediterranean world. Careful use of ditches, traps and wooden structure is also likely to limit the effectiveness of the large beasts substantially if the fight is on the ground of human's choosing.

So my conclusion is: even in the worst case (for humans) - i.e. the monsters need to be defeated in one big battle, there is no fundamental reason a mildly competent ancient general could not win such an engagement with troops to spare, using only tactics that were well-known at the time. The remaining challenges are logistical: how to rotate your troops at the frontline so that they get enough rest to stay effective for the whole long slaughter, stocking up on polearms etc.

The task becomes easier if you allow yourself to split the fighting into multiple battles. Most likely the humans can move faster than the monsters as ~20k humans can still somewhat effectively use existing roads (they would form a few km long formation) while the monsters are so numerous that if they want to stay concentrated, they have to move over the whole (and potentially difficult) country. If that's the case, humans could likely disengage the enemy at will (and get rest and resupply). To be more fancy one could also lure the monsters into a forest and start a forest fire to both reduce their numbers and split them into multiple bodies that could be defeated in detail.