Say that through some subterfuge and the element of surprise, a small, well equipped force of soldiers managed to wrest control of a castle from a government. The government wants that castle back, obviously and dispatches a much larger force to do so.

I know castles exist in order to allow a smaller force to hold against a larger force, but the problem comes from the addition of magic to this fantasy world. The governmental army will have magic, but my small strike force of characters will not, and as such what could the characters do to hold out in this case. I realize that this broadly depends on "what magic is available", so assume low to mid level D&D power scale. Mages are rare, and can shoot fire, move stone, create food, all kinds of things that would make an extended siege easy, but no reality warping, god tier stuff.

My main characters are that small well equipped force, and I would like them to be able to hold this position, in order to show them react to a more domestic life than the journeying soldiery so far. Ideally I'd like them to last throughout a winter, and then be forced to leave soon afterward. However honestly, it feels impossible to justify it without just saying "the walls are enchanted to be immune to magic". And if I did that I'd have the opposite problem of why would my characters ever be forced to leave!

Seeing as a castle is a defensive structure, what kind of defenses could it reasonably have to defend against such threats, in such a world, without resorting to using magic to make it completely unassailable?

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    $\begingroup$ A magical fireball is fast, but a bullet is still faster. This is the premise behind the anime "GATE," where the Japanese military finds itself in a magical fantasy world. Long story short, despite the inhabitants having magic, they get absolutely slaughtered by the advanced technology and tactics of a modern military. If your defenders have modern weaponry, they'll mop the floor with the magical attackers. $\endgroup$
    – stix
    Commented Jan 29, 2021 at 21:12
  • $\begingroup$ Easy solution for why they'd leave after so long if the castle can handle magic (as it should if magic is so common as to be used in your average siege): the castle gave them such an advantage over the attackers that after holding out for an entire season they grew careless and overconfident, allowing their enemies to find a way in and forcing them to flee in a hurry. Sun Tzu already said it: the opportunity to defeat the enemy is provided by the enemy itself. $\endgroup$ Commented Jan 29, 2021 at 21:34
  • $\begingroup$ Check out this Dragon Magazine edition with an article on exactly how to make castles supernatural-resistant annarchive.com/files/Drmg224.pdf $\endgroup$
    – DWKraus
    Commented Jan 30, 2021 at 0:35
  • $\begingroup$ By being smart. This story idea kept nagging at me until I realized that the story "Monument" by Loyd Biggle jr did something like this. The non magic users use the weaknesses of magic, or even the weaknesses of the culture, to win out in the end. Also the episode PK Tech Girl from Farscape, in which Ka D'argo wins a battle when he has no weapons by, eventually, inciting a mutiny amongst the opposing crew. $\endgroup$ Commented Jan 30, 2021 at 7:39

3 Answers 3


The Castle was Built with Magic in Mind

You do not put the time and resources into building something like a castle if you do not believe it to be defensible against a superior force. All of the features that evolved on castles over time (extended towers, crenulations, machicolations, arrowslits, moats with drawbridges, counter-siege engines, etc.) were all necessary countermeasures planned in advance to defended against every conceivable threat.

In your setting, your government has magic; so presumably, that means that other governments have magic too. This naturally means that your civilization already has generations worth of experience to draw upon when designing a castle about how to counter magical threats in a siege. If castles can't be magic-proofed, then there is no reason for them to exist in your setting at all.

When you look at all of the previous castle features I listed off, they all have two things in common. They are designed to allow you to be a threat to attackers while simultaneously preventing the attackers from being a treat to you; so, to continue this trend in castle design, I would suggest that the castle walls have been enchanted with magic wards designed to block spells from coming into the castle, while also allowing spells to be shot back out. Your defenders may not have spells they can shoot back out, but just being protected from spells coming in will be a huge tactical advantage.

  • $\begingroup$ You can add to this that even if you want mages to be present as defenders, those mages need to eat and sleep sometime if not prepare more spells. On top of that mages are likely belonging to rich elites due to what they can do, so they'll likely be irritated about extended sieges making their life difficult at all hours. That means that anyone is going to build some magical defences to at the very least buy time and get the mage awake enough to start throwing its own magic. You also dont want that mage to hold all the cards so a backup should he get idea's of bagaining to replace you is handy $\endgroup$
    – Demigan
    Commented Jan 29, 2021 at 21:53
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    $\begingroup$ There was a Dragon magazine article on exactly this. They suggest a variety of ways to make D&D castle resistant to magic and flying monsters/mages/things that can crawl up walls etc. annarchive.com/files/Drmg224.pdf $\endgroup$
    – DWKraus
    Commented Jan 30, 2021 at 0:34

The castle is remote and its former owners are distracted.

Your ragtag band of misfits was able to take the castle because the government is involved in some serious issues on the far side of the kingdom. This remote castle is not involved in those big doings and was defended in a cursory manner by a skeleton crew, the usual garrison having been relocated to help deal with the serious doings.

When the government gets the news that this castle has fallen, they are initially concerned that the serious issues have opened up a new front. But no - it is your ragtag band of misfits. The government knows who they are. They know your group is not allied with or related to the trouble that is their #1 concern. The government knows that your people do not even really have an agenda and probably wanted somewhere warm to stay the winter.

The minister rolls his eyes. "Either we will be able to go evict this crew in the spring, or we will not. And if we will not, it is because we will have larger concerns than who currently resides in Castle Maher."

I like the idea that the "large force" dispatched to this castle in fact consists of noncombatant family members of knights and nobles who are themselves engaged in dealing with aforementioned serious matters. The families were sent here because the castle is at a distance and perceived to be safe. Some of these are already in the castle when your group takes it. A lot more show up just as winter sets in. Your group has to decide what to do with them all. Nothing says "domestic life" like a bunch of kids and oldsters!

  • $\begingroup$ That's an interesting idea, simply don't have them siege it at all. Loses out on the small group overcoming insurmountable odds angle, but if I want an "action set piece" there is definitely options for that during the spring. Good suggestion. $\endgroup$ Commented Jan 29, 2021 at 19:27
  • $\begingroup$ Also if they take in the family member refugees and spend the winter with them, what next? I can imagine the scene when a force does come out in the spring to reclaim the castle but the refugees they have been living with either advocate for your band or help them escape. $\endgroup$
    – Willk
    Commented Jan 29, 2021 at 19:47
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    $\begingroup$ "Chase two rabbits, catch neither." I like it. $\endgroup$
    – Tom
    Commented Jan 31, 2021 at 23:14

Castle Defences

Your castle is going to have the same defences as any other castle -- walls, arrow slits, choke points to limit points of entry for the outside army, etc. What is less set is the kind of magical defences that the castle will have, either in the form of enchantments and/or wards on the castle itself or in the integration of magic into what we would already use. The other big question will be if your group of soldiers can use these enhanced defences, even if they themselves lack magical potential.

Oil cauldrons enchanted to refill slowly so that there is always boiling oil to pour on the invaders could be one such enhanced defence. Other magical defensive armaments could be finite, broken, or unpowered, but that might not be known to the people laying siege on the castle.

Likewise bluffing is a strategy. Keeing with the D&D analogy, there is a low-level spell that places an aura on something, but does not actually do anything else. These walls just might appear to be super magic proof, but most of it is a bluff.

Caveat: The Magic Elephant

As you have stated, magic is a thing in your world. As such, it is reasonable to think that there are enchanted walls -- castles will be designed to take magical assault into account. They likely will not be enchanted to repel everything, but they will take common spells used in a siege into account when creating them. And some uncommon spells if the castle is important enough or its owner rich enough. So they should be resistant/immune to spells to shape stone and earth for one.

This is not to say they are unassailable my magic -- certainly flying over the level of the walls and casting a Fireball or two down into the main area of the castle is a plan -- something a 5th or 6th level D&D caster could do. Likewise, if the spells fail, they will just be regular walls.

Why the Siege?

Other than governmental pride, my question is why would they siege a castle in winter? Magic really helps to answer that one -- it won't be a comfortable siege, but spells will take the largest bite off the invading forces by increasing comfort and ensuring that there is enough food and water to go around in the event of sabotage or a shortage.

To use D&D Terms, a 5th level Cleric can do a lot to support a group through food creation, water creation, and healing support for things that happen.

Training Siege

For whatever reason, the government does not value highly the castle that was taken. Or rather, they do not value highly retaking the castle immediately. Choose your reason.

As such, the force that they send are newer soldiers and leaders in training. It is a test to see how they act and react to the harsh conditions of winter, the burdens of command, and the logistics of handling a siege. This does not make it any less of a siege on the castle -- but it does mean that there will likely not be optimal decisions made as the leaders are not experienced veterans. They will still probe defences and try to gather intelligence, but these are not super ninja wizards.

Bonus point is that any mages sent are not there to siege the castle. Instead they are sent to make sure that the siege survives the winter without heavy casualties from the cold, accidental food shortages, and anything random that might cause them problems. Alternatively, it is also training for the mages as well.

Once spring comes, the evaluation is over and a more concerted effort to retake the castle is undertaken.


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