Seals are magical runes meant to restrain and restrict the movement of demons, limiting their range of movement and trapping them within the seal itself. Their are three variations of seals created for several classes of demons. Type 1 seals restrict the lowest classes, which are the weakest form of demons. Type 2 seals are for mid-level demons. Type 3 seals are made to restrict the highest and strongest class of demons. Applying the correct version of the rune is important to contain a certain level of demon, and knowing how strong the creature is beforehand is essential for the spell to work. Applying the most powerful version of the rune to a weak demon will not restrict it, and applying a type 1 seal to a powerful demon can be easily overpowered.

Seals are made through the use of mana, the magical energy that exists in all humans. Mages have gained mastery over their mana for the use of performing spells. To create a seal, a group of mages must work together and force their own mana into a created rune in order to power it. The more powerful the seal that is to be created, the more mana it requires from the mages to fuel it. Mana is a self-regenerating essence, so the amount that is applied will recycle itself and trap the demon within forever as long as it is not broken.

When items are created in society, there are usually several variations of it, with the cheapest being the most simple and limited. As technology grows and quality increases, it becomes more expensive compared to its predecessors. However, it can do everything that the previous generation could do much better and more efficiently, as well as add new capabilities that make it more valuable. The equivalent to this would be an Iphone 12 of 2020 to a blackberry of the early 2000s or a flip phone of today. A goal of magecraft is to create a seal that can contain all versions of demons regardless of class, in order to save time and expense, making it easy for mages to do their job without having to know the kind of demon they are dealing with beforehand, and no expense has been spared. However, all such attempts have failed.

What would prevent this kind of rune from being made possible?

  • $\begingroup$ This really borders on a fishing for ideas question, you are in complete control of how your magic system works and we have little idea of how it works. $\endgroup$
    – John
    Dec 18, 2020 at 17:34

6 Answers 6


Capture Method

Each of the three types of demons require a completely different to capture them in the sealing rune/array.

Type 1 Demons are weak, so the rune is basically an inescapable solid cage. The mana recycles back into the rune so the walls of this dimensional cage never weaken. Stronger demons can break through it because they simply outpower the walls that are created.

Type 3 Demons are strong, and the only thing that can realistically seal them is themselves. The runic array is designed to initially seal the demon, then use its own energy and power to reinforce the cage, effectively sealing itself. Why this does not work on weaker demons is that the walls are initially weak, and easy to break if the demon is not strong enough to reinforce the prison fast enough.

Type 2 Demons are in a strange middle ground -- too strong to be contained by just basic walls, and too weak for the self-sealing method to work efficiently. What mages came up with to solve this was to make their seals create a prison mage of strong and flexible walls. The walls of the prison are designed to bend but not break. A stronger demon can just overpower this seal, as they can the Type 1 seal. A weaker demon should be trapped by this seal on paper, but somehow keep escaping.

Gotta Catch 'Em All

So what does the method of capture have to do with creating a universal seal I hear you ask? It is clear by the question that a single universal method will not work for sealing a demon (or it has not been discovered yet). As such, with the current magitech, a combined approach seems to be the process that needs to be followed

So taking the methods, and follow the idea to its desired conclusion, this should indicate that a set of instructions should be sufficient to make a universal demon seal:

  • Build a cage for the weakest
  • After a point, make the cage flexible to prevent brute force attacks
  • After a second point, use the demon's own power to prevent escape

At this point, it starts to be more of a spell program than a spell. So the obvious way to prevent it from working is to prevent this kind of spell syntax from working. Sealing spells cannot make decisions or branch -- they only have one way to do something. This very reason was why the Type 2 Seal was even needed in the first place.

Abandoned Tech

An interesting premise is that this is an ancient method that will seal any demon already. Ancient mages rejected it for its side effects once the first Type 1 and 3 Seals were developed.

The original demon seal was universal -- but instead of a cage, it used chains. It bound a demon in sealing chains so that it could not escape. They were flexible enough to not break with pressure and could be fueled by their own power. To study them today, they had some of the attributes of the three types of seas we see today.

The drawback to these was that it was not a perfect seal in that the sealing chains left gaps that demonic power can escape through. While this prevented the seal from breaking and releasing the demon, it also means that demonic power was being leaked into the world at sealing locations. This was anywhere between annoying and bad depending on the entity sealed.

The cage-type seals both contained the demon and hid the energy so the chain-type seals were slowly abandoned in favour of them. But occasionally there is a problem, and they have to go looking back at these old seals to solve the problem.

In short, the side effects of a universal seal are too undesirable to use it and thus perfect it.

Product Testing.

So, you have improved the seals? Great, now test it.

Snarky perhaps, but how do you test a spell that is designed to hold a living thing? I doubt that your magitech corporation has demons on the payroll that consent to being sealed to test the efficacy of their new seals.1 While they can measure the effects on the world, or lack thereof, the fact that they will not be testing seals on the same demon may be an issue when it comes to reporting results.

Even if you can test a seal on a small number of demons, there is still the very real possibility that the sealing technology will be tuned to that subset of demons and the farther way from those subsets a demon is, the less likely the seal is to work fully.

1 Then again, they might. Long con by demons?


A goal of magecraft is to create a seal that can contain all versions of demons regardless of class, in order to save time and expense

This will be a frame challenge: such a seal is possible but will lead to more expenses and time.

Yes, you can make one but the complexity to set up such seal far outpaces the complexity of doing some scrying/divination and then preparing an appropriate seal.

Also possible that the added complexity of this universal seal makes the whole thing more brittle and thus more likely for a demon to break through the seal. To use your phone analogy, a phone from the early 2000s could be dropped or even thrown and suffer no ill effects. The tech was more robust and there wasn't that much of it. A modern phone which slips from your pocket might easily break, sometimes beyond repair. Would you trust a Nokia 3310 to hold off a demon trying to claw your face, or the latest iPhone?

Finally, let's reframe this a bit. A seal is a tool. Mages are specialists. In the real world, you won't really see a specialist use a completely universal tool for a specialised task. If you need to repair a watch, you won't just reach for the medium sized screwdriver over the fine one. If you're trying to build a house, you won't use a plain hammer when you want a mallet.

Specialists value robust instruments over one-size-fits-all ones. The latter are fine for very casual work. I can probably repair some stuff with a multi-tool but I have a cabinet of instruments if I need something serious. And "serious" here might just be assembling furniture. I won't trust a desk built with a multi-tool. I wouldn't enter a building, if I knew it was made with one. If somebody starts summoning a demon within the latest "multi-seal", I'd probably make a run for it.

  • $\begingroup$ A one size fits all screwdriver is certainly possible, but it’s much simpler, less expensive and less likely to cause problems if you just look at the screw and select the right kind of screwdriver from your toolkit. $\endgroup$
    – Joe Bloggs
    Dec 17, 2020 at 11:56
  • $\begingroup$ Could I run my thermostat off of a $1000 Ryzen 9? Sure I could. I can also run it off a 10¢ micro-controller. Engineering is the art of using the minimum resources necessary to meet the requirements. $\endgroup$
    – Matthew
    Dec 17, 2020 at 15:59
  • $\begingroup$ "run my thermostat off of a $1000 Ryzen 9? Sure I could." for some reason i suspect there might be a tad bit of compatibility issues there... $\endgroup$
    – Topcode
    Dec 17, 2020 at 16:13
  • $\begingroup$ I wouldn't trust a regular phone to protect me from a demon, but a Samsung Galaxy S? Oh, yeah! Just throw it and run as it explodes in the demon's face, I doubt they'll be able to find you after that! $\endgroup$
    – Alendyias
    Dec 17, 2020 at 21:28

Compare it with metals. Each metal has its own virtues, merits and shortcomings.

Some metals can be alloyed together and provide a better material for certain applications, but if you mix all metals together, you will hardly end up with anything useful.

Likewise, if you bring all the demons together, well, some of them might not like to be together and cause a violent reaction. Sort of what happens when you mix water and sodium.


The different demons arent actually different power, instead different types of the same demons.

When you create a seal, you use a different spell for each type of seal. One type of seal can only block on type of demon, you would have to cast each spell together in some way and end up using way more mana then just casting type 1 2 or 3. When you cast all 3 at a time in this "combined" spell it could also have other disadvantages, like less effective or not lasting forever like usual seals.


Physical size.

The rune is an approximation of an extraplanar structure. Consider a gate. A gate to confine elephants will let mice slip thru the bars. A gate to confine mice can be crushed or stepped over by an elephant.

Runes are the same. The multidimensional structure of the rune corresponds to the entities it is meant to exclude, and demon strength and "size" are always related. Probably they need greater size to house greater strength.

You could make an all purpose gate by layering 3 or more runes of different size on top of each other. This does not save any expense.


demon is a very broad word with very broad implications, an option here is each one having a charge of sorts at a molecular level this to make a multi-charm would leave gaps the demons could manifest though, however this would mean the only functional charms would be full encasing ones. you could have it so proximity to another charm causes fusing into a different material or complete nullification. or another option might be for the demons to react or summon a magic that reacts with the incorrect charm to create a gap. if it is god or magic centered then perhaps there's relics and no new ones can be crafted or those that could bless newer charms don't exist anymore or contact severed. the rune may have to be inscribed to give it power which means its limited by how small you can make inscription based on both tools and the required material it be made from. on another note entirely if you just want to delay it to a certain age you can have making such a think take a lengthy multiyear perhaps century long ritual,or maybe they faced a "witch trials" style even which limited their numbers and thus made certain rituals lost or at the very least slowed progress due to illegality.

Hope this helps!


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