There exists a strange dimension called the Margins of Reality. All supernatural things in the world come from here and are caused by what the natives call "Margin Spirits." In essence, these are Ideas that have "leaked" into the real world and changed things. These leaks are frequent and can happen anywhere at any time. These Ideas are called "Margin Spirits" because the natives have established a theory that there are people or things inside the Margins of Reality that want these supernatural changes to occur. What's more, supernatural things happen more often or with greater impact in locales that haven't seen upheaval or change recently.

A few examples of what supernatural changes can be wrought:

  • A rock is possessed by the Idea "BIG" and transforms into a mountain.
  • A tree is possessed by the Idea "MOTION" and transforms into an treant.
  • A house is possessed by the Idea "HUNGER" and transforms into a horrifying haunted house that attempts to lure victims to their doom.

Fortunately, people cannot be possessed by an Idea.

The Dilemma

In the average case, people tend to form large settlements for communal protection. However, the tendency for supernatural events to occur in a given settlement increases as the settlement grows in size due to having more people who each want more things, any of which could be the target of possession by an Idea, and the fact that larger settlements are indicative of a stable environment.

Pros and Cons of a Large Settlement (not an inclusive list)

  • Pro: More people means more opportunity for growth as a civilization
  • Pro: More people means more chances at a solution to supernatural events
  • Pro: Greater defenses against animals, beasts, and supernatural events that come from outside the settlement
  • Con: More stuff means more opportunities for Ideas to take hold
  • Con: Hard to form due to need for a stable environment and more likely to attract major supernatural events when they do

Pros and Cons of a Small Settlement (not an inclusive list)

  • Pro: Easier to maintain a stable environment
  • Pro: Fewer things to be victims of Ideas
  • Pro: Fewer people to care for
  • Con: Susceptible to being overwhelmed by external threats
  • Con: Less likely to be targeted for major supernatural events

So, in general, would society tend towards large or small settlements to combat the mixture of mundane challenges and supernatural events?

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    $\begingroup$ What is the growth rate? if I double the size of the city is it twice as likely to suddenly generate a monster house? $\endgroup$
    – Daron
    Jul 9, 2020 at 17:42
  • $\begingroup$ Or is it more like adding a hundred people doubles the chance? Then adding a hundred more doubles it again and so on? $\endgroup$
    – Daron
    Jul 9, 2020 at 17:43
  • $\begingroup$ @Daron There isn't a mathematical formula for it. $\endgroup$
    – Frostfyre
    Jul 9, 2020 at 17:57
  • $\begingroup$ “People cannot be possessed by an idea”? I beg to differ... $\endgroup$ Jul 9, 2020 at 18:08
  • $\begingroup$ @FranklinPezzutiDyer Little ideas, yes; big Ideas, no. :) (The reason for this is they are already possessed: gorilla + PURPOSE = human.) $\endgroup$
    – Frostfyre
    Jul 9, 2020 at 18:13

4 Answers 4


Depends on the Growth Rate.

The question is how the normal (dis)advantages of some size of settlement compare to those of a settlement of the same size where every so often a chaotic event happens. This is entirely dependent on how likely the events are. You say they are more likely for bigger settlements, but how does that work exactly?

Here are two examples where the answer is very different.

(1) Linear growth: Each person has say a 0.1% chance of triggering an EVENT per year. Say an event usually takes about 10 Protagonists to resolve. That means we need to hire 1 Protagonist per 100 people.

It makes no difference how the people are spread out. If they are all in little villages or in one big city we need the same number of Protagonists.

In fact, everything else remaining the same, this is an incentive for bigger settlement. If a village has 100 people it should have on average 1 Protagonist. But that's not enough to resolve even one event, so we should make all villages 1000 people or more.

Another point is that a city of 10,000 people has 100 Protagonists. They have different specialties so we have more versatility in where we sent them. Some will be more specialised to sent to which EVENT.

(2) Exponential growth: A group of 1000 triggers on average 1 event per year. But 2000 triggers on average 2 per year. And 3000 triggers on average 4 per year. it keeps going like this until 10,000 people trigger about 1000 events per year.

That means for the small group you only need 1 Protagonist per hundred. But as the group increases we need 10,000 protagonists. But wait that's all of them.

In the second system there is a huge disadvantage to big cities, and probably a hard cap before the city literally tears itself apart.

  • $\begingroup$ Hm. Well, my original plan was for the events to occur either on a whim or for plot reasons. You've made me realize I may need to come up with some occurrence metrics. $\endgroup$
    – Frostfyre
    Jul 9, 2020 at 18:37
  • $\begingroup$ @Frostfyre Then your best bet is probably (1) since then you can just bolt the chaos events onto a normal world, rather than having to restructure all of civilisation. $\endgroup$
    – Daron
    Jul 9, 2020 at 18:58
  • $\begingroup$ @For plot reasons it would help if people with stronger desires are more susceptible to events. That's why it keeps happening to the main cast even though it's fairly unlikely for other people. $\endgroup$
    – Daron
    Jul 9, 2020 at 19:02
  • $\begingroup$ I think you are missing something. The presence of humans isn't the only thing that determines how often supernatural events occur. I'm assuming a tree could turn into treant in a forest regardless of the presence of a huma settlement, Meaning your secluded village may still have to deal with monsters or such appearing in perhaps a 50 Km range or so (if they are drawn to the village in some way). $\endgroup$
    – Chebi
    Jul 9, 2020 at 19:09


There is a reason some people on this earth prefer very much to live alone, or in small communities, whereas others flock together to big cities. The reasons for this are very similar to the pros and cons you have listed in your question.

Larger cities make people feel safe as part of a crowd, but often come with a higher crime rate. Small cities tend to have lower crime rates but have a less experienced or capable police force.

The dynamic you described will probably amplify peoples opinion about their city size, but it will most likely not change. There might be fewer large cities, but they might be larger. People living in small communities might be more spread out. But you should remember both the countryside and the big cities provide their own unique resources, and are often co-dependant.

A thing you should consider as well is population density, people might want to live alone, but not have enough land available to do so. This might lead to hostile neighbours or sub-par living environments.


Regardless of whether or not people try to build large settlements, small settlements will remain predominant simply because no large city will last very long without being destroyed.

The potential for these Ideas to make sudden, drastic changes in the environment means that a single chance occurrence could wipe out a whole city. If, for instance, a rock is possessed by the Idea “BIG” and suddenly turned into a mountain, it will instantly destroy the entire city around it.

Even though the OP said there’s no “mathematical formula” governing these spirits, I’m going to do some math anyways. Sorry, I like math.

Here are some assumptions:

  • every object (however you want to define object) is possessed on any given day with probability $\alpha$. Possession-events are independent from each other and from previous days.
  • the probability of a possession-event being catastrophic and destroying the town (e.g. a stone turning into a mountain) has probability $\beta$.
  • the number of “objects” in a settlement grows roughly in proportion to its population. That is, in a town with $n$ people, the number of objects is roughly $\gamma n$, for some constant $\gamma$.

Consider a town with population $N$. The probability that the town is not destroyed on a given day is equal to $$(1-\alpha\beta)^{\gamma N}$$ Further, the probability that a town with population $N$ survives for $D$ days is equal to

$$(1-\alpha\beta)^{\gamma N D}$$

And the average number of days that a town with population $N$ survives intact is equal to

$$\frac{1}{1-(1-\alpha\beta)^{\gamma N}}\approx \frac{1}{\alpha\beta\gamma N}$$

This means that the expected duration of a town is roughly inversely proportional to its population. Double a town’s size, and you can expect it to survive for half as long. Oof.

  • $\begingroup$ I like math too! $\endgroup$
    – Frostfyre
    Jul 9, 2020 at 19:09
  • $\begingroup$ I'd like to challenge your third assumption. There will be a certain number of rocks beneath your village and within "mountain kill range", regarless of population. That means there would be an arguent for an optimally sized town where the extra population helps with the random occurrences more that they increase the chance of them happening. $\endgroup$
    – Chebi
    Jul 9, 2020 at 19:27
  • $\begingroup$ @Chebi Good point. I suppose that’s why it’s important to specify which “objects” are susceptible to transformation. Can atoms be possessed? If so, we’re all screwed regardless, because random crap will be happening constantly to every cell in our bodies. $\endgroup$ Jul 9, 2020 at 19:29
  • $\begingroup$ @Chebi For what it's worth, possession tends strongly towards living things; the rock -> mountain change was a once-in-a-timeline fluke. Franklin: Atoms are not "objects" according to my rules of possession. $\endgroup$
    – Frostfyre
    Jul 9, 2020 at 19:48
  • $\begingroup$ @Frostfyre Living things? So... what about microbes? That could be pretty catastrophic as well. I think it would be worth elaborating on the rules of your possession-system in the question (at least if you want a more specific answer). $\endgroup$ Jul 9, 2020 at 19:53

Okay, I've found a lot of your comments a very useful to better understand the magic surrounding chaotic possesion and I think I've found something helplful for your would inhabitants.

So, one of my concerns was that limiting city growth wouldn't be helpful if there was still a decent danger of a natural object surrounding your now small settlement becomming possesed. While this would still be a concern (and a relevant one for my answer), you've made it clear that most possesions would come for the objects from your settlements' inhabitants.

I think contrary to some assumtions, very small settlements woudn't exist. The reason being, they wouln't really last before the first attack by a Treant, a Mud golem or another mutated creature that required a defense by >20 fighting men or so (or I should actually say both fighting men and women, since in world where a threat is bount to jump out any mundane object I think women would have to know how to defned themselves).

I think while big cities wouldn't exist, at least until there's some way to make chaotic possiesions more manageable, since they'd be bound to too much disruption and large cities require a decent level of organization (food distribution, water, sewage systems, defense form invaders, disease prevention, etc). If you are constantly dealing with chaos, some of this other issues are bound to get out of hand.

On the other hand, smaller cities and towns (think up to about a few tousands or even in the low tens of thousands) would still be prevalent in my opinion. Not only they give reasonable defense from most external natural threats in the vicinity (of course, spontaneus mountains are still outside of what anyone could handle).

In addition, there are certain practices and policies people could take to lessen the risks. For instance, as you mentioned, one bench that seats two is as likely to change as a chair that seats one. So your people will naturally prefer the former over the later, as it will be considered safer. Even better if the benches are fixed to the table so that the whole thing is considered one object, and in turn the table can be fixed to the house. Same with wardroves and similar furniture. As for clothes, I hope you people like onesies cause they´ll be in fashion year round. The merits of underwear would be havily debated against the risk of it becoming possesed by words like "STRANGLING" or "TINY".

Sharing would be havily encouraged in your communities. Why have many more tools than needed if they can be kept in a shared shed among some neighbours and even further lock that shed down when not in use so that it may contain at least the smaller chaoric manifestations. Axes and such tools would probably be disasembled and the sharp bits be kept in metal or some other strong containers if possible. If one turned danegerous just throw the whole thing in to the furnace and melt it to death, recovering the metal later. Creature made of wood would be more manageable with them most damgerous being stone ones, for their sturdiness and potential size. So I guess stone isn't going to be a popular building material unless absolutely needed. Castles and walls can probably stay if they serve a good enough purpose of defending against invaders. Especialy if individual blocks aren't suitable for possesion. Stone houses, stone statues, and other non-essential buildings, probably hardly frowned upon.

Also, pests and animals that don't serve a purpose, they are probably exterminated. No one wants to deal with giant ants or venomous rats. Cat's and dogs can probably stay as they can hunt smaller creatures, and dogs could be trained to spot chaoitic manifestations if they have a characteristic smell or sound, to provide a faster response.

Lose rocks or trash laying around in the city streets, not good looking. Take it away. Your peolpe would probalby invent landfills ahead of thier time. They'd be pretty interesting places I'd wager. With a high density of mutation capable objects over time, there would be a bunch of crazy things over there. They would probably be dangerous places. But maybe also contain some valuables. Maybe an old suit of armor became "INDESTRUCTIBLE" or rusty sword "FIRETHROWING", or a cape "LEVITATING". That's an organic occurring magic item factory if I've ever seen one. You've got a natural dungeoneering system over there. Adventurer may be a preofession in it's own right in your world if you wanted to. If you want something more like a traditional dungeon then maybe have the items burriend in catacomb or maze-like underground structures (so that the creatures have a harder time getting out).

So in summary, with the cooperation of a population I think a settlement could rise to a moderate size with manageable risk, and there would even be certain forces pushing it in that direction. I think you have a really interesting system that caught my attention so I definitely think you have a lot there to explore in depth and come up with something quite unique.


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