I am a shopkeeper who sells food to sorcerers on a corner shop in the city of Monte Lacum. How can I stop Ice Sorcerers breaking into it and stealing the food?

Attempts to prevent being stolen from

I tried to put a PIN code on the iron door one night. The next morning, I found that an Ice Sorcerer had created layers of ice around the PIN lock and smashed it to bits. I have only 700 royals in savings (enough to pay an Air sorcerer for 1 week's guarding). Oh, also everyone within 1km wants to go to my shop for food because it sells Extra Energy Food (EEF) that provides a much higher calorie-to-content ratio.


*'*Set in 13th century Europe**'

Everyone is a sorcerer, specialising in one of the elements: Air (can fly), Earth (can cause earthquakes), Fire (can shoot fireballs), Water (can cause tidal waves), Light (can temporarily blind people), Dark (can send out their shadow), Life (can use the power of all living plants and animals nearby, excluding humans), Ice (freezes things - see above), Lightning (casts lightning - Emperor Roberto II is one), Shockwave (casts a shockwave), Metal (can shape metal - used by blacksmiths) and Null (partially immune to sorcery - used by people like me).

I have worked out how to trap all other types of sorcerers.

There are pets, yes (I have a dog named Terrar) but that isn't important.

Monte Lacum is a big draw for Earth, Water and Ice sorcerers (and Air ones, to a lesser degree).

My shop is like a supermarket, but without the non-food items.


I have nearly no money and am looking for ways to protect my shop (for more than 1 week - see above).

  • 5
    $\begingroup$ What, exactly, do Ice Sorcerers do? Do they create water content to freeze, condense it out of the atmosphere, or what? Does the ice creation follow thermodynamic laws or not? Also, why is the Air Sorcerer your prospective guard? Are there some social reasons other types of sorcerer couldn't guard the place? $\endgroup$
    – Lord Dust
    Sep 1, 2016 at 6:14
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    $\begingroup$ You know, no lock was ever meant to stop anyone from getting in. Their only function is to slow down intruder, and give owner or law enforcement time to react. $\endgroup$
    – Mołot
    Sep 1, 2016 at 6:44
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    $\begingroup$ "supermarket, but without the non-food items" it's called a grocery store ;-) $\endgroup$ Sep 1, 2016 at 12:07
  • 3
    $\begingroup$ Are you looking for creative solutions, or just solutions period? The issues you describe have long been mitigated by basic safe construction techniques. You can't break into them simply by breaking the combination device. The parts that matter are inside, and well guarded. The best you can do is make it so that nobody can get in, by mashing up the combination wheels, and then you have to go get a locksmith to torch the safe open. It's a terribly droll solution, but it's used in real life against adversaries who have access to liquid nitrogen. $\endgroup$
    – Cort Ammon
    Sep 1, 2016 at 14:30
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    $\begingroup$ You have the most successful shop in town yet you have little to no money. I think you need a "finances sorcerer" before anything else. $\endgroup$
    – xDaizu
    Sep 2, 2016 at 8:42

10 Answers 10


Hide it: You can place the food on a secret room, for example behind the classic cabinet with his side panel which slides only when you press a little button, invisible if you don't know where it is.

Set an alarm: Place a pile of metallic cup, plate or bucket on every entrance in order to create noise if someone try to enter the store at night. This will alert you and the air sorcerer. The dog can also fulfill the same role. This solution implies that you or your air sorcerer sleep in the shop.

Set traps: Due to your limited fund, fancy trap with trapped slab and arrows are not a solution, but even a simple bucket fillet with brick can be a mortal trap when you place it on the top of a strategical door.

  • 2
    $\begingroup$ Very useful! I tried the last option and it worked spectacularly. The next morning, I found the thief knocked out. $\endgroup$
    – 1089
    Sep 2, 2016 at 21:07

You want to make your door out of a magical superconductor, this way it can

  1. Redirect lightning to the earth
  2. dump/extract heat to the some conveniently placed marble/obsidian when subjected to extreme temperatures

This means that your ice wizard will need to be able to freeze a much larger space than the door he can see. you could link this underground strata so that he is effectively trying to freeze the entire continental plate!

The great thing about this is, it's completely passive and the door will always "normalise" to the temperature of the linked material. making for a slightly spooky effect when you touch it as it will always be a different temperature to it's surroundings.

  • 1
    $\begingroup$ Note: you may be thinking of Larry Nivens superconductors which don't match real life superconductors. Real life ones don't superconduct heat. $\endgroup$
    – Murphy
    Sep 2, 2016 at 10:30
  • $\begingroup$ @Murphy also magic superconductors, the rules are a bit loose $\endgroup$
    – Chris J
    Sep 2, 2016 at 10:39
  • $\begingroup$ This may fall afoul of the "I have nearly no money" constraint. A giant magical superconductor doesn't sound cheap. $\endgroup$
    – aroth
    Sep 2, 2016 at 14:12
  • $\begingroup$ @aroth you can use the existing door and have a decent crafty sorcerer to enchant it, "link this door's state to the bedrock" if they owe you a favour you can get it on mate's rates $\endgroup$
    – Chris J
    Sep 2, 2016 at 14:32
  • $\begingroup$ @ChrisJ what if you always redirect part of the heat to a large area in front of the door? While standing there he would freeze himself. You could enhance it, using a tiny antechamber, which freezes if the door does! $\endgroup$
    – Ludi
    Sep 2, 2016 at 16:59

I really love the superconductor answer from Chris J, even though I'll offer you a way more aggressive alternative.

What if the entrance is a small corridor, after which is the door to your shop. This corridor would be filled with Thermotraps.

Thermotraps should be a trap triggered by a huge drop in the temperature. For doing so you simply need that the trigger of the trap consists of a material that quickly contracts due to a change in temperature.

When the door becomes cooler, the trigger contracts, which activates your trap and KABOOM! kills your burglar.

Edit: As noted by Mason Wheeler, remember to disarm the thermotrap during working hours unless you want to kill paying costumers on chilling winters. Still, though, there's the temperature needed to completely shred the lock should be way lower than the one you achieve during winter.

  • 1
    $\begingroup$ Great idea, right up until a cold snap comes through and kills paying customers during daylight hours. $\endgroup$ Sep 1, 2016 at 15:06

Make the door and lock out of brass.

Lowering the temperature of most metals increases their hardness and can make them brittle because it makes harder for crystals to slide past one another. This a problem for ferrous materials like iron because they are pretty inflexible already.

Copper alloys, however, can actually get stronger at low temperatures because they are so malleable to begin with. If you made your door out of brass, it would be pretty much immune to Ice Wizards.

enter image description here

The US Department of Commerce publishes this useful guide to the low-temperature properties of copper alloys.

  • 1
    $\begingroup$ A great idea but somewhat lacking in background - perhaps consider explaining what the graphs are showing, or link to related source material. $\endgroup$
    – Samthere
    Sep 2, 2016 at 10:10


As the owner of one of the most popular shops in Monte Lacum, you should be able to drum up some influence (and some wealth) to address the issue of rampant crime.

Mobilize the merchants guild, and find a sympathetic ear among relevant town officials. Put on the pressure to get the town guard into shape and properly protect the merchant quarter.

Or other, seedier things, like turning popular opinion against ice mages and getting them drummed out of town, or striking a deal with the thieves guild for protection.

  • $\begingroup$ Since everyone likes the store people will get very angry when some Ice mage makes everyone go hungry for a day just to get some lousy 700 royals. Using technical (magical) solutions to social problems generally doesn't work so well, using politics is the way to go. And in this case I would even expect people to volunteer; guard duty once a month is worth food every day. $\endgroup$
    – nwp
    Sep 2, 2016 at 7:45
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    $\begingroup$ ´like turning popular opinion against ice mages and getting them drummed out of town´ ...there's a couple thiefs who happen to be ice mages, so we criminalize ALL Ice mages until they are banished from the city, not accepted in magic universities and/or are reduced to ghettos. And not just this town, when the word spread this will happen all around the country, affecting hundred of innocent ice mages for generations... do you see where I am going? Yep, magism. Thank you for doing this world a ton worse for everyone. $\endgroup$
    – xDaizu
    Sep 2, 2016 at 8:32

Your question reminds me of electricity. Destroying a door by freezing it with ice reminds me of lightning. How do you mitigate the effect of lightning? You do so by spreading the electricity into the earth. So is it possible to create a large pool of water that would absorb the latent heat of fusion of the ice, and therefore make ice impossible to form?

Or, to make it simpler, would it be possible simply not to make a door? Having access to so much sorcery powers, you probably don't need an ordinary iron door.

  • 1
    $\begingroup$ It will still freeze a) thermal conductivity isn't infinite, you can freeze one part of the door while other still has environment temperature b) you can freeze only a part of water - it is exactly what happens in nature all the time. But general idea - redirect "heat" somewhere else - is nice $\endgroup$
    – Deo
    Sep 2, 2016 at 15:38

one way

Maybe a bit grotesque but make a leather pouch for your lock from the skin of a null sorcerer. I'm sure it would be harder to freeze that way or prevent it from becoming brittle.

Another way

Lock the lock in a lock box that uses a key lock. make the lock box have a hidden compartment the is unlocked when u lock the lock box. in this compartment put liquid that turn to give off gases to knock out someone. this way if someone opens the lockbox by smashing it, it will release the knockout gas.

This assumes after the first 2 thieves, found out cold in front of your shop, get arrested 1 day after the other, warding off other thieves so you don't have to get another lockbox everyday (maybe u can get a good deal if u buy bulk though :/)

  • 1
    $\begingroup$ Considering the shop-keeper is a null-sorcerer... Although Life sorcerers would find it harder to heal the shop-keeper, it wouldn't be impossible for them to heal it enough for skin to naturally re-form, so long as the damaged flesh wasn't irritated while healing. $\endgroup$
    – wizzwizz4
    Sep 2, 2016 at 10:28
  • $\begingroup$ What's a null sorcerer? $\endgroup$
    – Ludi
    Sep 2, 2016 at 16:55
  • 1
    $\begingroup$ @Ludi it's specified int he questions the different type of magical affinties people have in the OP's universe. null is a type of person/sorcerer : ...and Null (partially immune to sorcery - used by people like me) $\endgroup$
    – Sarfaraaz
    Sep 5, 2016 at 5:55

Bimetallic strip

See wiki.

Make a coil similar to one in a gif, attach it to a plate in front of the lock, so if temperature lowers plate slides and blocks the lock entirely. Like this: mad paint skillz

Don't forget to add a spring or something similar to create threshold, so it wouldn't get blocked by usual temperature fluctuations.


Use a lock that is designed in such a way that if unlocked properly, it opens the door, but if smashed, releases some kind of trap. Maybe it is attached to a chain that holds up a large spiked object, or keeps a trap door closed.


Given that you have an iron door to secure your shop I'll make the assumption that the surrounding walls to your shop are not wood and are instead stone or perhaps something even stronger.

If that is the case might I suggest fitting a secure fireplace/furnace either directly behind your door (To one side on the inside of your shop) or even better directly above your door with a grill/grating to allow heat to flow over the door (Despite heat rising it should be more than hot enough). Provided it generates enough heat (Which an open coal fire should) and providing you can keep the fire going for the night until you return in the morning this should produce far too much heat around the pin lock that you already have set up that no ice sorcerer should be able to freeze the lock again.

Having the fire above the door will also prevent ice sorcerers from simply filling up the fireplace/furnace with water when attempting to freeze your burning material as the water produced will simply fall on to the floor.


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