Military Effects of D&D Magic

Last week, I discussed how the spells in Dungeons and Dragons might totally reshape the politics and economics of a D&D world. Today, I’ll dive into how spells would revolutionize warfare.

Are ordinary soldiers obsolete? 

People often assume that in a setting with wizards capable of calling down Meteor Swarms or other incredibly powerful spells, the common soldier has no role to play. However, that’s not true. 

Even in a magic-heavy setting, non-magic users will typically outnumber even the weakest spellcasters a hundred to one. At the end of my previous post, I estimated that in a million-person kingdom, only about 16 people would be able to cast truly high level (7+) spells, and probably no more than a thousand would be significantly more powerful than the average soldier. 

Secondly, there are serious limitations to what even a powerful spellcaster can do on a battlefield. One big problem spellcasters face is that the range of DnD spells is usually pretty short. Fireball has a range of 150 feet, and Shatter only 60. Compare that to a basic longbow, with an optimum range of 150 feet and a maximum range of 600 feet. To cast spells, a spellcaster has to put themselves well within range of mundane arrows, as well as their opposing spellcasters. 

The longbow, or as I call it, the Wizardslayer 3000

The other big problem for spellcasters is their limited endurance. In D&D, a mid-level spellcaster might have about 10-15 spell slots. That means that after a minute or two of intense combat, a spellcaster will have burned through their entire day’s allotment of spells. A peasant with a bow, on the other hand, can fire arrows all day (so long as ammunition holds out). Battles in premodern warfare tended to last hours, so spellcasters have to be ultra-conservative in how they use resources. 

Finally, soldiers are not useful just for their ability to fight on a battlefield. Soldiers are how a state controls territory. Soldiers collect taxes, regulate trade, repel bandits, stop rebellions, and do all the other tasks too dangerous for unarmed people, but too mundane for spellcasters. 

In many ways, spellcasters are analogous to tanks in modern warfare. Tanks are far more devastating, faster, and better protected than an infantryman, but tanks cannot do everything. 

Battlefield Roles of Spellcasters

So what role would spellcasters play on a battlefield? The most dangerous spells in a typical spellcaster’s arsenal are large area of effect spells like Fireball or the aforementioned Meteor Swarm. These would act like explosive artillery, blasting huge craters into the ground and killing many soldiers. The downside, however, is the aforementioned short range and limited uses of these spells. 

To compensate, a wise commander might concentrate the majority of his spellcasters into a single decisive attack to smash the enemy at the decisive moment of the battle, just as the Germans during World War II concentrated their tanks into an armored spearhead. Spells like Haste and Expeditious Retreat could make the attack supernaturally fast, thus negating the range problem, and, if all went well, it might win the battle altogether before the spellcasters ran out of gas. 

An example of how tanks, followed by infantry, can cause a breakthrough and encircle enemy lines

Such an attack be a powerful, if risky, way for commanders to win the battle in one decisive charge. However, it would inevitably mean high casualties for spellcasters. That’s a problem because, as discussed in my previous article, spellcasters are also an invaluable agricultural and economic tool, arguably more useful to the state during times of peace than war. In short, minimizing the deaths of spellcasters might sometimes be even more important that winning a battle.

Other options are also available to commanders. Spellcasters might instead play a less direct role in battle, using non-combat spells to gain information and help communications. These sorts of utility roles would cause far fewer precious spellcasters to die, and extend the usefulness of spellcasters to the whole day, rather than a few minutes. 

Consider the role spellcasters might play in reconnaissance. Polymorphing into a bird or Fly enable spellcasters to cover immense distances and scout out enemy movements, just as early planes did in World War I. It’s easy to forget that before modern times, all recon was by sight. Just like in World War I, scouts might also have the job of finding and ‘shooting down’ enemy scouts. Soldiers might watch bizarre spellcaster duels taking place in the clouds. 

Similarly, Sending would have an enormous (if not very exciting) impact on the battlefield. Communication was one of the largest obstacles facing premodern commanders. The fastest way to communicate was by sending messengers on horses, which could take hours in bad conditions. Sending would allow a commander to send messages to his subordinates instantly. 

Ordinary Soldier Tactics

What role would regular soldiers play in a battlefield full of magic users? Although soldiers would remain important, their role would certainly change. medieval and renaissance battlefields typically involved close-ordered and slow-moving blocks of soldiers. These blocks, however, would get torn apart by fireballs and other area of effect spells, just as soldiers died in their thousands to artillery in the First World War. 

Instead, we might expect to see soldiers using more modern tactics, like move and fire. Soldiers would fight in small, dispersed units acting over a wide area and using cover. These units would probe the battle lines on their own initiative, picking off spellcasters with bow shots, seizing positions, and encircling the enemy with the greatest possible speed. 

The disadvantage with that kind of advanced tactics is that it requires far more training for soldiers to execute move and fire tactics effectively. Close order blocks, on the other hand, require less experience on the part of the soldiers. Therefore, we might expect militaries in a D&D world to become far more professionalized, to enable soldiers to use anti-magic tactics.


During the Medieval period, pitched battles were exceedingly rare. More often, leaders preferred to opt for the less risky strategy of besieging castles. Sieges, then, were arguably a more important component of medieval warfare than battles. Some high level spells like Earthquake have the potential to completely destroy a fortress in a matter of minutes, but remember that in order to cast the spell, the caster must spend a minute within easy reach of all the castle’s ranged attacks. On the other hand, Mighty Fortress can build fortresses as fast as Earthquake can destroy them.

Besiegers would also have other tactics. Chains of Tiny Huts could serve as makeshift bunkers through which attackers could gradually creep closer to the walls. Flight spells could enable an entire new direction of attack. Small numbers of spellcasters could use Dimension Door to teleport directly into a fortress, or try to sneak in through Invisibility. Such tactics, however, would be risky and potentially result in high casualties among priceless magic users.

Defenders, however, would also have tactics available to them. Wall of Stone could repair any breach in a wall in a matter of seconds. Time is on the defender’s side too. With spells like Goodberry capable of producing large quantities of food, it would be almost impossible to starve out a garrison that included magic users. Finally, long-term teleportation resources like Teleportation Circle would mean that no fortress is entirely alone – there’s always the possibility that reinforcements will arrive directly in the fortress from the capital city. These teleportation circles would be a huge strategic asset, so much so that the whole point of a siege might be to capture the teleportation circle.

Both sides would make great use of non-magical soldiers, both for construction and for combat. We might expect to see ordinary soldiers at the frontlines of every combat, since magic users are simply too precious to throw directly at enemy positions.

Sieges in Dungeons and Dragons would be shorter than their real-world counterparts, but far bloodier. Attackers would have at their disposal many methods to break into a fortress, but each would be far from foolproof, and run the risk of disaster. Defenders too, would have to be on the lookout from attacks from any direction. In real history, sieges have always featured immense creativity and adapting tactics. Magic would only enhance that desperate resourcefulness.

The ancient Siege of Syracuse, when the Greek genius Archimedes invented bizarre devices to keep the attacking Romans at bay

Finally, we must consider what kinds of wars would appear in a Dungeons and Dragons setting. As I discussed last week, the lifespan-enhancing spells in D&D should make realms with powerful autocrats a very common feature of most worlds. Accordingly, wars might not be waged between nations and peoples, but between powerful individuals who use their many subordinates as tools. The decisive moments of wars, then, might not be battles or sieges but assassination.

Dungeons and Dragons offers players a multitude of ways to wage wars. The way you run your game is up to you, but I hope this guide has provided some inspiration for a few ways warfare might look in a fantasy world.

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