Why does magical defensive equipment not work in layers?

Question

This question graduated from the Sandbox for Proposed Questions

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Question

In my world, clothing and armor can be enchanted to grant protective effects. Clothing can be as thin as sheer silk, but still be strong enough to completely nullify a blow from a warhammer (or stronger).

My question is this. Given the information about my magic system below, what mechanic can I use to prevent a wealthy person from wearing a dozen layers of thin, enchanted clothing and becoming essentially invincible?

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My Magic System

How is magic manifested?

Magic is energy in the world that casters take into themselves to become their own energy, which they then use for enchantments. However, a skilled magician can draw from ambient energy (has the least effect) or draw directly from their own energy (has the greatest effect), or between the two (moderates the effect).

What's the cost of using it?

Magicians pay nothing to cast an enchantment, but the amount of energy (ambient or personal) is limited. If there isn't enough energy to complete an enchantment, it will fail.

Can a person wear two magic rings on the same finger?

This question was asked in the Sandbox and I understand its point. I would prefer "yes" because I'd like people to have, for example, both a Ring of Fireball and a Ring of Shield on one finger. However, if a person stacks a bunch of Rings of Shield on all their fingers... that's actually what I'm trying to stop. So at the moment, I'm not sure what to do. (The outcome of this question will help me make that decision.)

What stops a magic user from casting a spell?

Running out of energy obviously stops the spell. Knocking them unconscious stops a spell. Disturbing them too much stops the spell (but the bar is set really high for most spells.) There are no "null-magic zones" where all spells are stopped no matter what, because even if you drain the ambient energy, the user will usually still have an internal storage of energy.

(Extra) Setting Flavor

The setting is a mix of (800s) East Asia and (1400s) Europe. Lots of tall, steep mountains with rugged terrain. Magic feels mystical rather than scientific. Medieval fantasy genre with Asian influence.

Answer 1

No one knows why, and that's okay for your setting

Magic feels mystical rather than scientific.

Normally I don't like answers that say you don't need to know the answer to a question, but this is one of those rare cases where knowing the answer is actually counter productive to the setting. Any explanation we could give would be a law of nature in your world making magic seem scientific rather than mystical. So the very act of explaining why it happens goes against the theme of your setting.

Part of what makes not explaining it okay is because we are already used to seeing this mechanic in so many different videogames that modern audiences don't really question it anymore. What you are describing is so common that it already has a name that most gamers recognize: "non-stacking buffs", and they are so ubiquitous in game settings that no one really questions WHY they exist anymore, they just accept that they do exist and move on.

While video games are more forgiving about mechanics that only exist for balancing purposes, a narrative setting might be less so. The best way to approach this problem in a narrative setting without making magic less mysterious is to lampshade it:

Apprentice: Master, if all these shirts give you minor fire resistance, why not just stack them together and become super fire resistant?

Master: Hahah, oh silly boy, magic does not work like that! I would only become as fire resistant as the best shirt in the stack.

Apprentice: Why is that?

Master: Why does a suit of chainmail making casting a spell so much harder? Why can I use a teleportation spell to teleport my enemies, but I can not use it to teleport the heads off of my enemies? How does a dragon fly with such small wings? If these questions had answers, then it would not be magic, would it? Magic is what it is, nothing more, nothing less.

Lampshading is a useful convention where you know an aspect of your world defies common logic; so, instead of leaving your audience to question why people don't do something that seems obvious, you simply explain (or better yet, show) that it does not work in your setting.

My favorite example of this is the difference between StarTrek and SG:Atlantis transporters:

Both settings have slower than light torpedos and transporters. In StarTrek, everyone at some point asks themselves why no one ever transports a torpedo directly into an enemy ship, but in SG:Atlantis it is one of the very first things humans think to do once they get transporter technology, but it only takes the Wraith a few moments to figure out how to jam the transporters thus removing the obvious exploit from the narrative. No one needs to understand how or why transporter jamming works, they just need to know that it is a thing.

Answer 2

So an idea would be to say that all enchanted items have a limited radius to draw magic from, say 3 meters. we could also say that the more enchanted items you carry the more they try to draw from the same magic, like siblings fighting over a toy. This means that all the enchanted items become less powerful, the more items you have.

so say someone had 10 rings on and 15 layers of enchanted clothing, then they would be less powerful than someone with 3 rings and 1 layer of enchanted clothing, as the second person protection would both be stronger and attacks stronger. This is because as they have less enchanted items taking magic from around the mage, thus there is more efficient magic use, thus more energy for the enchanted items to utilise.

This could also limit mages power, as they become more powerful the larger their reach/radius to be able to gather magic.

Answer 3

In two abjurations stacking a person in this world has two independently designed abjurations that are doing the same thing.

For a digital metaphor, look at anti virus software. You can install 2, 3, or more vendors’ antivirus packages; but they aren’t meant to work together. And in most cases they work against one another - either repeating the same checks (at a cost of more processing time), but yielding no additional protection, or worse quarantining one another’s work, actively working against one another.

The same may be true of any magical effects that do the same thing to the same person at the same time, but weren’t designed to work in concert like that.

It might be that the +2 ring of protection is two +1 rings designed to get along. Still they won’t stack well past their design limits, because the arcanists involved didn’t design that extra capacity. A +3 ring might be this extra extension of the magic, done by a competent arcanist.

Answer 4

Magic combinations have unanticipated effects.

Your 10 silks might be additive as your wearer hopes. Maybe they are more than that. Maybe he becomes untouchable by the world. Maybe he becomes imperceptible to the world. He is like a ghost, on another plane. Maybe he is untouchable even to himself and he cannot grab them to take them off. Invincible! And getting thirsty...

Magic items can be synergistic, or antagonistic. Stacking magic always produces effects outside of what the original magics did. These "stack effects" might vary according to time, place or person and they are very difficult to use predictable.

But very fun to write about!

Answer 5

Magic resonance/radiation

To take this in a slightly different direction, rather than disallowing stacking, each magical item could emit a magic "radiation" of sorts.

While the radiation itself could be harmless and some items could be combined safely, stacking too many small sources or combining powerful sources of magic could result in the magical equivalent of nuclear "critical mass" and have devastating effects on their user and anyone/anything around them.

The effect could vary based on the types of magic imbued into these items, but as long as someone has attempted it and others have heard the tales, they will be very careful about how many items are used at once.

Answer 6

Parallel Execution
Enchantment effects trigger simultaneously, not sequentially. They run in parallel and have no "knowledge" of each other. The one that takes longest and resolves last overwrites the others.

Here are some examples:
Cloak of the Rock: 10 damage protection
Shirt of Minor Protection: 5 damage protection

First, let's look at sequential resolution:

1. Attack does 100 damage
2. Cloak receives 100 as input and reduces it to 90
3. Shirt receives 90 as input and reduces it to 85
4. Net protection: 15

Now, parallel resolution:

1. Attack does 100 damage
2. Cloak and Shirt both trigger with 100 as input
3. Shirt (being simpler) resolves first, setting result to 95
4. Cloak resolves, setting result to 90
5. Net protection: 10

There are a couple major benefits to this system. First: the more powerful effect is likely to take the longest, thus becoming the end result. Second: separate, distinct effects on the same item could be handled individually.

Here's an example of this:
Cloak of the Pointy Rock: 10 damage resistance, 5 damage to attacker
Shirt of Thorny Protection: 5 damage resistance, 10 damage to attacker

1. Attack does 100 damage
2. Cloak resistance, Cloak damage, Shirt resistance and Shirt damage trigger
3. Shirt protection resolves, setting damage taken to 95
4. Cloak damage resolves, setting damage dealt to 5
5. Cloak protection resolves, setting damage taken to 90
6. Shirt damage resolves, setting damage dealt to 10
7. Net result: Protection: 10, Damage to attacker: 10

It might sound a little complicated, but in the end it greatly simplifies the system. If enchantments overlap, just take the highest value and ignore the rest. This way you can stack up as many shirts or rings or hats or whatever you want as long as they each provide some unique value. If you want more protection, the only option is to acquire an item with a greater protection enchantment than anything you already have.

Answer 7

Magic Shields Should Block Magic

This should seem pretty obvious and self explanatory, such that this is its own solution. A magic defensive item that doesn't block magical attacks from harming the wearer is useless, therefore enchanted defensive items have the property that they block magic. Now, how will a magic device underneath another magic shield get its ambient energy to power its own defensive enchantments if there is a shield around it that is blocking magical powers? It cannot. The ambient magic to power the second artifact will not be able to pass through the existing magic barrier.

• The magical artifacts are commanded by the user and the user alone. They are not commanded by another artifact. Therefore, a mage can cast their own magic freely, but other defensive artifacts cannot order each other to let themselves through each other's barriers. Such a backdoor would put every defensive artifact user at risk from an override magic made to turn defensive artifacts off in combat, or by their own artifacts opening holes in their own defenses to recharge each other.

• Another thought is that the magical barriers will reject and push against each other. How can a mere unthinking artifact tell the difference from a blade of hard magic and a hard magic shield? The user could still be bludgeoned or crushed to death by a blunt magic attack, so they would protect against everything. This would include another bit of magic encircling your existing defenses. After all, those shields could in theory close and crush the wearer, so the inner layer would have ample reason to push additional barriers away from the inside.

Answer 8

Limited ambient magic.

If you just gather power and set it off, it will do whatever it does and then run out. A fireball or a magical shield happens and then vanishes. In order to produce a continual effect, there needs to be a continual supply of magical energy.

However, there's only so much energy to go around. If you have 10 different magical items on your person, they each only get 1/10th of the magical energy from you and your vicinity. Adding more items spreads that energy more thinly, without significantly increasing the amount available. You'll have more magical effects, but they'll be weaker (which might be acceptable for some applications that don't need that much raw power, but would limit how much you could stack up at once).

Answer 9

Enchanted Objects are not Sources of power, but merely Filters for Manifesting.

Each Enchanted object would simply allow a use to take their internal magical energy and to manifest it in a way designed by the object. The higher quality the object, the better it manifests it. A very high quality Ring of Shielding will allow you to take your energy and convert it very effectively into a Shield. A lower quality one does the same thing, but at a worse rate. Likely, each ring also has a maximum amount of energy it can convert.

With those mechanics, you cannot stack things indefinitely. Each Object can convert a certain amount of energy. Once the total of your Objects exceeds your own total Energy, they start to compete for the resources.

In this world, a person's Magical Energy levels acts like an interval maximum capacity and determines how many objects they can work with at once and of what quality.

Answer 10

Animism is true for spells.

Whenever you cast a spell, the spell is actually sentient. This helps in casting the spell. It is more intelligent and able to react to circumstances than might otherwise be expected.

But, if you try to cast the same spell several times in a row, it usually gets jealous and fights other versions. They all want to be your spell, so they'll destroy the other inferior copies. The normal result of this is both spells collapsing.

Answer 11

Magical Resistors

Well, if you are okay with a bit of tweaking of your magic system, you could draw from how resistors and electricity does work. For that, your magic-user would act as some kind of electric conductor, the magic as some kind of electricity.

If a spell hits a target that can conduct magic, it would apply magical energy on that target. Feel free to use the aura of living things or stuff like that for the magic conductor.

Anyway, now the interesting part: To safeguard themself from the dangerous magic electricity, one can wear rings of protection... or other stuff that acts to magic like a resistor to electricity. The more magic-ohm, the better the effect.

Now, multiple protective elements on the same conductor are connected in parallel (not sure if that is correct in English... "parallel schalten" in German). And like electric resistors, magic energy connected in parallel do not add up, but... share the magic.

Or better, you get hit with magic while wearing three rings of magic resistance with 100magiOhm each.

Rmagic = (1/100)+(1/100)+(1/100)

if you want more resistance, you need to connect in serial, which happens by... three magic user, each wearing one ring of magic resistance, holding hands:

Rmagic = 100 + 100 + 100

would that work for you?

Answer 12

What happens when an unstoppable force of armor gets pushed back and hits an immoveable silk cloth? They become brittle and prone to breaking apart.

Even if you magically can make silk strong enough to withstand a War Hammer blow, it's still going to have to move to have the user wears it.

If you put armor on top of it, now you have two things that need to move with the user - and the upper layer responds by changes from the lower layer. Unless your armor is designed to withstand those movement effects and be kind of stilted in movement, that's going to have to happen.

You'll probably appear to be lucky at first, but when the upper layer suddenly needs to slightly adjust to a bit of power involved and force being soaked up, it clashes into the lower layer.

If it does so at multiple points, you might end up with an effect like the one in this webcomic.

In that comic, a mage is asked to choose spells from wands to destroy a dummy that has an existing shield around it.

Their solution? use a wand to cast another shield spell on top of it, then cast essentially Magic Missile - at the set of shields.

Answer 13

Interferences.

Enchantments work like waves in a field. Very similar enchantments act like coherent waves, and interfere with each other. Their results are unpredictable. Theoretically, if they were totally coherent, that is and exactly the same, then their effects would stack perfectly, like constructive interferences (or annul perfectly, being destructive interferences). But since that is not possible in practice (even the slightest difference in the conditions of the creation of the enchantment, or in the enchantment techniques induces minor differences), the interference becomes completely unpredictable:

• some parts of the effect may stack: your two layers may be very good at shielding against bladed objects
• but some parts may interfere negatively: it might be even worse than regular cloth at defending against blunt damage
• worse, the parts that interfere constructively / destructively might vary over time. You might end up with a blinking armor, that is very resistant for one second, then very weak for the following one, then again very resistant, and repeat. Or a cloth that is resistant to a random type of weapon at each time… Or a ring that fires in a random direction… They can be very powerful items, but you really don’t want to use them.

Note that with that setting, it might be easy to interfere with another item user by using a similar item…

In contrast, very different enchantments act like incoherent waves and don’t interfere with each other.

Answer 14

Magic is a field

A magical shield works by deflecting the mana field around it. This will protect you from attacks both physical and magical.

Now with gravity every charge attracts every other charge. With electricity, attraction and repulsion depend on charge signal. Let's say with mana all charges repel each other.

This means that if you are wearing both a ring of fire resistance and a pair of pants of levitation, you will be physically unable to scratch your own butt.

Good luck getting that enchanted armor plate inside that enchanted silk shirt.

Answer 15

You basically give the answer: there is a limited amount of mana available before it all stops working. Wearing several layers of armor just depletes your mana supply that much faster.

Using a few dozen rings would still limit you. I assume they would be activated with mental orders, so you would have to focus on each ring seperately to cast your spell. Even then you "simply" burn through your mana faster.

If you truly require it you can add limits like a maximum mana consumption rate per person, limiting the maximum things you can power simultaneously. Artifacts could also use mana regardless of you using them or not, meaning it takes mana to simply wear more and you can't have extra's as backup. You can also introduce things like mana burn if you use too much mana in a short timespan, or let different magical artifacts suck mana from other artifacts causing their supply to be haphazard or making it impossible for some things to be powered because another artifact is in the way.

Answer 16

Mana exhaust

Depleted Mana is a thing and needs to escape into the environment as it interferes with spells working by wearing multiple layers you risk all of them becoming ineffective due to the exhaust. Depleted mana is hard to control as it clocks up any spell that touches which then in turn produces even more depleted mana.

This is usually not a problem, but as areas infused with magic prevent depleted mana from diffusing through it multiple layers are essentially a balloon that fills until catastrophic failure due to ever faster growing "depleted mana" concentration.

Answer 17

Stacking is permissible, but its not feasible unless items are low quality.

But the main limitation is how many rings will fit on your fingers (or toes).

Stored magic is good for X uses

For a magical vest to nullify the energy of a blow from a warhammer, a similar amount of energy needs to be put into the vest in the first place. Once the energy is depleted, it just becomes a normal vest again.

Some people choose to put defensive magic into rings instead of vests. These tend to last longer because they use, and nullify, a smaller portion of magic at a given time. In the case of a heavy blow, much of the force still makes it through. Some paranoid individuals acquire, and enchant, two dozen poorly fitting rings, jammed onto all their fingers, or toes. The smaller the better, and if it cuts off the circulation it only means the rings won't fall off - At least, not before their fingers.

Suppose an individual is correct to be so paranoid, at the end of the day, and his life, the only difference could be that one assassin is sent to kill him discretely, or half a dozen assassins are sent to clobber him to death in an alley with hammers.

Suitable materials uncommon

Not all materials are suitable for all kinds of enchantments, and some are clearly better than others. Some materials are better as magical conductors, and others as magical insulators. Some will hold onto magic for a long time, whereas others will bleed magic quite quickly. Sometimes impurities will cause a material to react strangely, or dangerously, when infused with magic.

Ultimately, you're limited by whatever happens to be available on the market, or what you can import.

And, unless you are creating magic items for yourself, then as a buyer you need a seller too, or vice versa.

For a buyer, because the best rings are rare, you will settle for a few crappy rings of shield that need replacing every other adventure.

For a seller, because the best materials are rare, (and because there are many many willing buyers for cheap magical items) its more profitible to create a few dozen crappy rings of shield that can be sold to all sorts of people.

Its not worth the money

A handful of high quality magic rings, such as to make an individual almost invulnerable, would bankrupt anyone, and make them a walking target.

Besides, they're only almost invulnerable to hard blows. They wouldn't prevent someone from stealing the rings straight from their hands. And a vest that blocks warhammer blows is still easily saturated with flammable oil.

So they're not really invulnerable.

Answer 18

Late entry here: Assuming magic is some sort of a wave over ether, they interfere with one another. With sufficient distance, the effect is negligible. After all strength of a field diminishes with the square of the distance. Different type of magic work as they have different frequencies. Even there might reduction in effectiveness in similar magic too.

Answer 19

I like the idea of the actual mechanism of a shield spell is that it is a surface that absorbs energy too close to your person. That energy could be physical or magical. A second shield spell would be magical energy close to your person and the multiple shield spells would essentially short each other out as the surfaces tried to absorb each others energy.