Put Flourishes, Fairy Tales, and Folk Beliefs in Your Fantasy World

Something fantasy world builders tend to do is

1. Take some interesting little aesthetic notion, often borrowed from a story, a history book, folklore, or a random generator;
2. Transform it into a fantasy element with thematically appropriate magical properties.

And that's great. But this is a call to sometimes not transform that little notion into actual 'functional' magic!

Earth's history is absolutely crammed full of little details, curiosities, artistic elements, superstitions, taboos, dead-end inventions, beliefs, art forms, and rumours that don't map onto anything impactful/real/important/true. Why wouldn't a fantasy world be similarly overflowing with these?

We live in the information age and people now still believe all sorts of completely preposterous things, not even as a matter of survival or entrenched cultural memory. In a classic pre-industrial fantasy world where the ground state is ignorance, people are going to deal with the great mysterious unknown around them by (a) trying to work out what works, and (b) just making stuff up. Both types of 'information' will be propagated. That's how people work, and the people in your fantasy world should feel like people.

Here's some suggestions.

Superstitions about dangers

Not every supposed way of keeping the monsters away actually does something. How boring would that be? Our world is full of superstitions meant to keep away monsters which don't even exist. That means you should add popular measures against goblins, vampires, spirits, ghouls, ogres, drakes, basilisks, and so on which simply do not work.

Remember: Nobody has enough information to know what's true and what's not. Even if the idea of confirmation bias has been invented in your world, the average uneducated person isn't going to have heard of it, and won't truck with it if they somehow have. Just like the average undereducated person in our world, and again – we're in an information age.

Superstitions about locales

Some places are sacred or taboo because of personal local history, not because of an innately magical nature.

You can have a big old battlefield without ghosts, and deep dangerous pits that aren't bottomless. The holy grove can just be regular holy rather than regularly dispensing miracles. If nobody goes to the place where the wicked Old Master was stoned to death, it doesn't have to be a portal to the realm of punishment, and the place where his sprawling manor was burned doesn't have to be a nightmarish megadungeon.

It's fine if some places work like this. But a world without unfounded local superstitions rings hollow.

Fairy tales, folk lore, and mythology

Here's a list of the world's fairy tales. There are many thousands of them and the list is incomplete. Like the vast majority of information from history, the most fairy tales never survived to pass into the written record. Note that none of these stories, as far as we can tell, are true.

The good news is that there's so many of them, you can just grab a few at random to fling into your own world and nobody's going to be familiar enough with the corpus to tell.

Folklore is deep and broad.

How about this rule of thumb: for every fairytale and mythological creature you put in your fantasy novel or game, add one that's not actually real in-world, just folklore being perpetuated. Fairies are real in the fantasy world, so people there believe in little fluttering proboscidate flingletons, which aren't. The inscrutable sphinx is real, so people believe in the twelve-metre-tall caustic tintosmaum, which isn't.

Religions, creation myths, and philosophy

Without making a claim in any particular direction, if you assume the world's major religious beliefs are incompatible with each other in terms of truth value, then a logical minimum of 5.4 billion people make a false set of beliefs central to their world view. And a possible maximum equal to the world's current population of 7.9 billion.

Now, I'll grant that (again, avoiding particular claims) our world doesn't have fantasy RPG clerics getting their daily allotted three or dozen or thirty verifiable magical miracles. But truth spreads slowly outside the information age. The existence in a fantasy setting of an extremely interventionist real pantheon (if you use that classic TTRPG trope) doesn't actually preclude local worship of a supposedly interventionist fake pantheon. Doubly so if it takes expertise to distinguish clerical magic from other kinds of magic.

It all depends on the nature of your cosmology, but personally I like when deities are standoffish or nonexistent, and weird new cults and religions pop up like mushrooms, and everybody thinks they're worshipping the real god(s) but there's no way, or no practical way, to be really sure. That rings true to me.

Either way, I suggest including some religious ceremonies that don't do anything (except make people feel good and forge stronger community bonds and so on). Religious rites don't have to have direct supernatural outcomes. You don't have to take the D&D route of turning blessings, ceremonies, funeral rites, holy water, holy symbols, etc, into spells and items with practical gameplay effects.

Pseudosciences and fake magics

Things like astrology and alchemy and the system of medieval humours needn't be in-game systems of magic or science. It's fine if you do want to play things that way, because these pseudosciences are flavourful and people have enough familiarity with them that they know what to expect (widespread modern misunderstandings of what 'alchemy' really meant notwithstanding). But if you do, you should definitely invent new pseudosciences for your fantasy people to get caught up in.

Again: People in our world, where magic doesn't exist, have believed in all sorts of magic, on the back of no evidence whatsoever. People in a world where they can occasionally see magic working should be more likely to have their minds open to such things.

That means that alongside pseudosciences, a fantasy world should have 'pseudomagics'. Piscomancy! Rust prevention magic! Soliferrous auras! Longevity rituals! Charms against moths! Whole new fields of supposed arcana! Is that local warlock a low-level magic-user, an ambitious dabbler with exactly one trick, a deliberate con artist, or completely deluded? It should be very difficult for a non-expert to tell.

Our actual history also has tons of objects that people placed significance in and ascribed powers to. Consider for example the 'Sator square' (an acrostic word square in Latin). It puts out fires. It eases childbirth. It cures toothaches. It's the basis for a love potion. It cures aquaphobia. It finds witches. Inscribe it on bread to cure rabies and insanity. Write it in pigeon blood to make a wish come true. Etch it into your fingernails to cure jaundice.

The Sator square obviously doesn't actually do any of those things. But people really believed it did. A fantasy world should have all sorts of things like this.

Terrain features

Our planet is home to lots of remarkable, awe-inspiring geography. In a low-technology world, real-world terrain can be a big challenge. Mountain passes can be extremely deadly because of the low rate of success of people tackling them, not because they're haunted by spirits or dimensionally scrunched or stalked by a gigapredator.

For every fantasy terrain element, include at least a couple of mundane ones.

Rumours

A healthy proportion of rumours should be completely spurious. But from a TTRPG gameplay perspective, don't go overboard. Make sure some rumours are very obviously false, as well as some more subtly false ones.

A neat effect for verisimilitude is to spin up false rumours based on things the player characters did or witnessed.

Flourishes, artworks, and personal styles

A neat little aesthetic detail doesn't have to be enhanced by fantasy (meta)physics.

A company of mercenaries march with a noose instead of a battle standard; it has no magical powers. The local villages have a specialist crop; it doesn't give you temporary hit points or make you levitate or drool blood, it's just funny-coloured pears. A distant monastery teaches a distinct style of martial arts that isn't supernaturally powerful. And some distant monasteries stick to beekeeping, illuminating manuscripts, and overeating.

We know of lots of little artistic embellishments, hoaxes, and weird experiments from pre-industrial history. The Voynich manuscript is a big one. People made sword blades with guns attached (and vice versa) as early as the 1500s. Sure, things like this can be the basis for unique powerful artefacts, but they don't have to be. Some of them should be prototypes that just don't work, or novel weapons that aren't actually as good as well-established ones, or an artist's cryptic drawings of a dream they had, or deliberate hoaxes. The strange, mysterious, whimsical, and exotic doesn't have to be translated into 'it's magic and has purpose X'. People on Earth have made all sorts of strange, mysterious, whimsical, and exotic things; all of them have been mundane, and they have been no less special for that.

Conclusion

To make a fantasy world feel real and lived-in, don't just fill it with fantasy. Remember to add little human-feeling elements from the real world, where pretty often a cigar is just a cigar.

Fantasy pseudo-anachronism part two: Aetheric boogaloo

Following up on yesterday's post, here are some thoughts on pseudo-anachronisms that didn't end up in the main article.

Additions

First, there were a couple of pseudo-anachronisms I had intended to mention. Nice beds with mattresses and pillows are major investments, certainly not something every person owned, even when they're just pallets made from straw sitting on the floor. (If you think a bed is expensive today, consider that it would have been a large fraction of a house's value in many pre-industrial places and times.) Also, inns for travelers to stay in. Inns were only common on major roads, pilgrim and trade routes, and in cities and market towns. The chances of a random village having an inn would be close to zero, even a village in the middle of civilisation. And even in a reputable inn, it would be a luxury to get your own private bed that you didn't have to share with a couple of strangers or traveling companions, let alone getting your own private room!

To have nice beds and pervasive inns in our fantasy world, we need a reason to have a culture of travel, in particular to non-notable destinations. We also need a cheaper way of making sleep furniture – maybe some ancient artefact has been churning beds out at a rate of fifty per day for thousands of years, or maybe there's a widespread plague of puffball pigeons (all feathers and no flesh), or maybe when a domesticated slime dies it dries up into something superficially like a beanbag chair.

Second, reader Lauren suggested the addition of "well-lit rooms after sunset". It's true! If you've tried to light a room with candles before, you've found that candle light is really very weak. Any kind of fire doesn't, uh, hold a candle to electric lighting. Lauren also pointed out that many modern people are used to the ambient light pollution of a big modern city; complete darkness is very disorienting. It's hard to keep your balance standing up in true darkness, let alone move around, but TTRPG rule penalties are often just a slap on the wrist. As with many things, inconvenient truths get handwaved away unless they provide excitement in the game.

I think well-lit rooms at night is particularly common in visual arts and film, where the viewer's ability to see most of the shot is pretty much the most important thing.

So 'convenient modern lighting' is a fantasy pseudo-anachronism. It's one that any number of fantastic technologies could solve (glowing magical crystals, cold-burning lanterns, the ubiquitous luminescent dungeon wall fungi, minor spells and charms, enchanted or holy candles, unusually bright domesticated fireflies, rushlights from the will'o'wisp marshes, whatever). Think carefully before making it a solved problem for the common person, though: clean, cheap, portable, bright light like we have at hand nowadays is a powerful technology. It takes terror away from the night and eclipses and deep dark caves. It drastically changes warfare. It changes sleep patterns and therefore labour patterns and local economies. It removes a constraint that can serve to drive gameplay.

Missing technologies

Rarely, fantasy takes things away from the generic 1300s-to-1600s technological milieu, rather than adding pseudo-anachronistic technologies.

For example, central heating, chewing gum, concrete, contraception, ice skates, and lighthouses were all invented thousands of years ago. I've seen a setting where characters in a snowy town had no way to cross a lake which froze every winter. And there's no excuse for not having a lighthouse guarding the dangerous shoals near a major wealthy port city. Some of the others aren't likely to come up, depending on what kind of ground the fantasy is going to cover.

Complex financial instruments, too, are fairly old (the word "credit" appeared in English in the 1520s, and at the time English-speaking states were economically a bit of a backwater; I don't know much about the history of banking but I would be surprised if continental Europe didn't have entrenched banking and other institutions in centuries prior, and the Islamic world and the East earlier still). I think sometimes TTRPG settings leave out promissory notes, banknotes, loans and interest payments, insurance policies, and so on due to a false perception that these are modern innovations.

The elephant in the room in this regard, of course, is gunpowder. Cannons were widespread in the West from the start of our supposed fantasy technological band, and early man-portable guns were in use well before plate armour reached its apogee. In China and its neighbours, gunpowder had been used for at least five hundred years prior to the period, initially as an incendiary weapon.

There are good reasons for not wanting gunpowder in a setting, reasons which have been discussed to bits. Everyone reaches a different answer to the question (some, possibly, because of misapprehensions imported from modernity about how powerful, fast, cheap, light, or accurate an early gun could be; I personally don't think preindustrial firearms being 'too good' is an adequate reason to exclude them from a fantasy setting). Gygax was notoriously against gunpowder in D&D, going so far as to say that the laws of physics in his fantasy universe were such that chemical reactions were weaker. I don't think that's a great solution, because it's both underspecific and implies weird knock-on effects.

If we want a world where 'black powder' gunpowder was just never invented, is that historically plausible? On the face of it, no. It's three ingredients, of which sulphur is very common in nature, charcoal is an incredibly important part of metalworking technology, and saltpeter can be refined from fairly common mineral deposits or bat guano. Additionally, 'classic' fantasy has early chemist analogues trying things out (I think modern fantasy has sadly transformed the word 'alchemist' to mostly mean 'magic potion-maker', rather than 'a philosopher obsessed with the idea of attaining physical, mental, and spiritual perfection via a mixture of study, experiment, religious ceremony, allegory, chemical means, mystery cults, etc').

But what that argument overlooks is that having access to magic might impede the development of gunpowder weaponry. Early experiments with explosive or incendiary mixtures probably wouldn't have been (a) taken as far, (b) seen as something remarkable, or (c) suggestive of exciting military applications, if two streets over from the workshop was an academy of war wizards suiting up for another day of hurling explosive fireballs, turning city walls to mud, and setting things on fire with their minds. Even assuming magical arts were at the time in their infancy rather than developed, they would have a competitive advantage due to their comparative versatility. So, inverted pseudo-anachronism: Solved.

(Conversely, if you wanted to take it in the other direction, and have gunpowder keep up with or surpass violent forms of magic, a world with fantasy materials might have better ingredients for a propellant. Materials that were more common, cheaper to make, easier to discover, safer to store, produced a more powerful reaction, burned smokelessly, negated the sound of their own explosion, or whatever.)

Pseudo-anachronistic systemic technologies

There were a few technologies I left out of the first article because they are more processes than inventions.

1. Classic fantasy has machines but no factory mass production.

There's an artificer, wright, engineer, or (sigh) 'alchemist' who makes devices. There's steam power, clockwork, waterwheel power, or complex systems of gravity power or compressed springs powering elaborate mechanical traps. There might be non-magical 'automata'. Sometimes it's almost a genre shift into steampunk or clockpunk. Sometimes it's subtle: the dungeon gates open and close with the right series of lever pulls and Detect Magic doesn't turn anything up, but further details about the mechanism aren't forthcoming.

Luckily for our settings, there are major societal factors necessary for factory mass production to flourish. It's not enough to have the idea and the metalworking skill. Labour must be at least moderately expensive (compared to thoroughly pre-industrial eras, not compared to today). There has to be the wealth and systemic control to acquire, move, and stockpile large quantities of raw resources. There must be pretty good ways to transport input and output goods. There must be at least a little hint of standardisation in the cultural zeitgeist. Things must be sufficiently peaceful and stable locally that the wealthy feel confident investing huge amounts of capital starting up a new kind of business whose nature is that it must be continually fed or suffer major costs. And it probably helps if there are enormous costly wars going on in the background to drive both demand and development.

Two thousand years ago, the Ancient Greeks had clockwork, a simple steam engine, and Heron of Alexandria described mechanical automata and a vending machine (a coin-operated mechanical holy water dispenser). But the conditions weren't right for industrialisation: It wasn't Steam Engine Time.

Still, if you want to play it safe, consider adding a rare, non-scaleable magical element to the setting's contraptions (some bit of fantasy metallurgy or alternative physics power source or unique irreplaceable artefact).

2. Classic fantasy implies advanced food production.

My impression of the typical TTRPG fantasy milieu is that even small settlements have great numbers of skilled workers outside the fields of food and textile production. Compare that to almost all preindustrial places and times, where the farmer-to-specialist ratio is somewhere between 90:10 and 99:1. The implication is advanced food production technology, but this is seldom directly shown.

There's two avenues to resolve this. You could say there's an enormous spiderweb of little farming hamlets and fishing villages, mostly ignored by the setting focus, diligently toiling to feed and clothe themselves and send their crop of food or textiles to market to pay their taxes (or send them directly to the tax collector, in less moneyed societies).

Or you could add the milieu-appropriate equivalent of spray pesticides, antibiotics, massive greenhouses, John Deere tractors, chemical fertilisers, advanced irrigation, and GMO crops. Let's say that stirge blood repels all insect larvae, and breaks down into a decent fantasy fertiliser. Water mages harness tiny elementals for drainage and irrigation. Weather witches work the weather. Migrating flocks of giant eagles regularly fix the soil nitrogen. The obsidian bullock pulls a plough slowly, but forever, night and day, without needing to eat or drink. A growthstone is costly, but all plants within two leagues of one grow at twice the rate, so you just have to keep up with the weeding. The peaceful living dead keep birds away for a while before degrading and nourishing the loam. And to cover gaps, the magic temple is happy to dispense endless miracle bread to the sufficiently needy.

3. In classic fantasy, big things don't decay.

Speaking of nourishing the loam... In the real world, everything is subject to entropy. Even stone degrades over time. There are startlingly close to zero stone buildings whose original roofs have stood the test of centuries. Earth settles, tunnels collapse. Most metals corrode. Wood rots or gets eaten, even in the dry. And – you know where I'm going with this – dungeons aren't usually well known for being dry. Ancient megastructures like lost castles and sprawling dungeons are sort of a fantasy anachronism, in that they are basically supernaturally well-preserved archaeological sites. In our world, furnishings and materials in them would be rotten within years, everything mechanical would have completely seized up within decades, the entrances (at a minimum) would get thoroughly sealed by a bunch of debris blowing in, and eventually the structure's integrity would fail.

This is of course no fun. Luckily there are plenty of possibilities. Lingering enchantments. Automata or invisible demons or extensions of the Gygaxian 'cleanup crew' which eat dust and grit and drifts of leaves. Magical materials that don't corrode or rot. Something to bear in mind is that most of these anti-entropy fantasy technologies are going to be valuable to people in the world, so by adding verisimilitude to your dungeons and ancient monuments you are also adding stuff that people are going to want to mine/harvest/tame/imitate and put in their own homes.

4. Classic fantasy makes outdated arms and armours contemporaneous with later ones.

Okay, this is mostly just a pet peeve, but it's close enough to the topic for me to justify cramming it in.

Particularly in the case of armour, your generic fantasy setting offers armours from radically different warfare/civilian contexts (almost always getting the armour itself wrong, but that's another story) as if any of them could be reasonable choices. In practice, people going into battle wore the best armour they could afford, perhaps modulated slightly by considerations of comfort. Let's look at mail vs plate, which is the biggest example (apart perhaps from 'leather armour' which is somehow both protective enough to sometimes be chosen over metal and quiet/fast to move around in; yeesh).

If a setting has the technology, expertise, and capital investment to make plate harness, then a fully protective suit of mail (hauberk including coif + aventail + chausses + gloves etc) is strictly worse than a suit of plate armour: the mail is either heavier or much thinner (because of ring overlap!), and more expensive (it takes more labour to make and rivet the large number of rings than to shape the smaller number of plates, and both are kinds of skilled labour!), and less protective (because mail flexes at points other than the joints!), and no less encumbering (assuming the plate armour is properly made, you can't do yoga in it, but that's about the limit of its limits).

The only advantages you could argue for mail are that it's slightly less hot to wear, due to its breathability (except, it tended to be worn over thicker clothing), and that it's easier to don and doff (definitely true: maybe twenty or thirty times faster, and you don't need assistance from a servant or colleague). Did both mail and plate exist at the same time? Sure; transitional armours increasingly covered the body with plate and retained mail at the tricky gaps (goussets, and then just voiders). Should a setting book place 'full plate' next to 'chain mail' and 'leather clothing armour' as options that just have different tradeoffs? No way.

Can we find a good rationale for having mail hauberks in the same setting as sophisticated high-coverage plate armour? Only, I think, at places and times when expertise in making armour plates is tightly controlled and/or slowly leaking out into the wider world. The only good reason to offer both these armours as reasonable options to player characters is if the massive difference in time to don/doff them is actually going to matter in play, and this must be the way the opportunity cost is framed instead of nonsense like 'plate costs more than mail' or 'plate is heavier than mail'.

This all applies to some extent to weaponry, too: fantasy TTRPGs love big lists of weapons from across many centuries, and some of them ought to be modeled as strict improvements of others. And to weapons platforms, like the chariot, which was thoroughly superseded by horseback riding, but still pops up in fantasy from time to time. Also the galley, which has three core assets (incredible maneuverability, naval ram, and capacity for beach landings) and three core drawbacks (high crew requirement, low cargo capacity, and relative fragility), but I've seen settings which included galley-like ships to evoke an Ancient feel while managing to ignore all of those factors.

Arms and armour are the products of a continuous technological competition – hence the term 'arms race' – and classic fantasy almost never includes what you would actually expect: weapons and armour (and tactics, troop formations, earthworks, etc) that are specifically designed for fighting giant enemies, invisible enemies, winged enemies, hordes of extremely small enemies, enemies that can't be cut or pierced, enemies that are slow but kill with a touch, and so on. Instead, at best, real-world weapons are used against them in novel ways. This is one of the few areas where fantasy actually needs to make more stuff up.

Pseudo-anachronistic societal features

Finally, I'm going to briefly go over a few things that aren't technologies. They're arguably pseudo-anachronistic, but are beyond the main scope of what I've been talking about with and frankly would need a whole series of articles to get into, and touch on topics which deserve a deep and sober treatment. For many of them I also think they could have become widespread features of societies earlier in our history, they just didn't happen to do so.

Actually, in an attempt to rein in my impulse to go on typing for hours, I'll switch to bullet points. These tropes show up in 'classic' fantasy quite often:

• General stores and grocery shops. Pretty modern idea.
• Lots of off-the-shelf products rather than things being custom-made, commissioned, or at least assembled on the spot. Historically, if you wanted to buy a knife, you'd likely visit a blade seller (who sells blades bought from a blade maker), and a hilt maker, and possibly even a separate knife maker to join them together if neither of the first two offered that service, and then you would go somewhere else to get a sheath made for it. If you were rich, you would possibly have any or all of those parts made to your preferences, and then might visit yet another craftsperson specialising in decorations (embellishing, engraving, insetting, etc).
• Civil police forces, or town guards who for some reason serve as constables. Not completely unheard of historically, but you're more likely to run into the local aristocrat's enforcers, or a town militia/guard with strictly military responsibilities, or just three people (a reeve, a coroner, and a magistrate) to be the law system for an entire shire, county, or small fief.
  
• Minor professions inexplicably organised into guilds; guilds that lack a religious/charitable structure; guilds operating like labour unions rather than corporations trying to suppress competition; guilds envisioned by people who learned the word from MMOs; guilds for major military technologies that really ought to be state-controlled... I could go on. I usually just shake my head and assume the word 'guild' is a spotty translation from the invented language the characters are speaking, not meant to bear any relation to the real world.
• The (correct, to be clear) modern perception held by almost all individuals and even by most states that war is bad.
• The notion that a war is likely to be for some abstract goal of 'power' or to extend a ruler's 'reach' rather than for territory and loot. In a world where land equals wealth, a successful war is a financial investment with a huge payoff (things like holy wars, wars of succession, etc, notwithstanding).
• People (correctly, to be clear) being viscerally and morally repulsed by what we now call war crimes and torture 'even' against 'the other side'. It's a depressing reflection of how groups of people operate that this is only a modern concept.
• Modern principles of individual liberty and rights, personal equality, and other individual rights. Anyone with basic knowledge of history knows that these were incredibly hard-earned and we are lucky to mostly now live in societies that have them at least in principle. It's not clear whether fantasy imports these because we're so immersed in them or because it's not fun to play without them.
  
• People living without major societal obligations and without a rigid societal, contractual, or familial relationship with the people ruling them. e.g., vassalage. I think fantasy settings tend to just pay lip service here, because it's not fun to have to bend the knee to your 'betters'.
• Conversely, in some settings, absolute tyranny existing unchallenged. Arguably more historically plausible, but even more plausible would be: the lieutenants and rich vassals think the rulers have far too much power + the rulers think they're giving up too much power and are trying to claw it back + there's a backdrop of masses of poor tenants and peasants desperately trying to get their established rights upheld. See e.g. the Magna Carta.
• (Pseudo-)democracies where everyone is franchised.
• Large numbers of empowered women with equal rights and with societal roles overlapping with those of men (or without distinct societal roles). Again, to be clear, a good thing, but rare historically. I have absolutely no expertise here but I usually see an explanation for how the systemic oppression of women came about that goes [average male physical strength advantage + power derives from strength-based violence + societies were more likely to succeed when the powerful set the rules + people tend to support existing rules (or, successful societies encourage supporting existing rules) → men seize and then hold and maintain power almost exclusively]. The good news is that you can excise this from a fantasy world by having magic more powerful than strength, or by reducing biological differences between the sexes, or by having interventionist gods who support equality, etc.
• More generally, no bigotry, slavery, or systemic prejudice. Sometimes this is because everyday common people are space aliens, by which I mean they aren't under-educated, clannish, selfish, fearful, violent, and ignorant of the wider world. Sometimes people are portrayed plausibly but intolerance magically doesn't happen at a wider scale. There are good and obvious reasons not to want bigotry in your setting or to confront it in your games, but (and now this list is just making me sad) pervasive intolerance has historical verisimilitude. Yeesh. How about we say that the fantasy world's populations are massively cosmopolitan, driven by ancient diasporas of hundreds or preferably thousands of peoples; everyone looks different to each other, even very locally, and innumerable culture are constantly blending. Or maybe we resort to magical divine intervention again to fix things.
• Speaking of which, there's the trope of 'everyone's religious beliefs are strictly compatible'. In a classic TTRPG fantasy, the gods definitely exist, everyone agrees on what they're like, everyone mostly agrees on their names, most people worship a single god even though there's a pantheon, and nobody is erroneously worshipping a god who doesn't provably (or provably doesn't) exist. This has always been quite funny to me. Maybe I'll write an article about interesting alternatives.
• Immortality as a desideratum only of evildoers (e.g., liches and sorcerer-kings). Likely imported from major modern religions; I don't think many nonreligious people are keen to grow old and die. The trope is kind of compatible with there provably being a good afterlife, but that's not always the case in a fantasy world, especially when you're not one of the tiny number of people with a divine magic pipeline.
  

There we go. If you think I missed any notable pseudo-anachronism, leave a comment!

Four kinds of fantasy setting peeves

Personally, our peeves when it comes to the tropes in fantasy books, TTRPGs, and shows can be reduced to four categories. Our favourite works are those that are careful about all of them.

Category 1. Yes We Are Super Pedantic.

Armour made of interlinked rings has a name. It's 'mail', not 'chain mail'. If you want to be period-appropriate, you might say 'maille' or 'mayle'. Armour made of thin lames of metal has a name. It's 'lamellar armour', not 'splinted mail'. The preposterous place we're in with pervasive fantasy armours that are mis-named or just plain stupid can be traced back to Victorian antiquaries and burgeoning medievalists like Grose and Meyrick. They chose to use 'mail' to mean 'metal armour', contra its historical meaning, and invented a bunch of armours (banded mail, tegulated mail, splinted mail, etc) that are historically unattested!

A gorgon is a mythological monster or demon from ancient Greece with a visage that turned people to stone. Stheno, Euryale, and Medusa were the names of the three gorgons. Medusa, and in later stories all the gorgons, had serpents for hair. Medusa was the only mortal gorgon. Having 'medusas' and then unrelated 'gorgons' is like calling countries 'australias' and then saying that the word 'countries' means 'sports teams'.

Historically, alchemy has been more about enlightenment, spiritual refinement, and purity of the self, than it has been about mystical proto-chemistry.

Necromancy means getting information from the (spirits of the) dead, not animating dead bodies.

...And so on.

Category 2. No Thought Given to Consequences.

'Fantasy' doesn't mean 'anything can happen at any time without underlying rule or predictable reason'. That's a description of a dream sequence, or certain strains of postmodernism. Sometimes we get peeved by encountering medieval facades with no real thought given to the consequences of having magic and monsters.

Even something as seemingly essential as the towering stone castle is the product of social and political forces: castle building is a consequence of a fractured state that lacks strong central coordination, instead delegating power to local or regional leaders willing and able to use violence to maintain control. Those leaders build castles (i.e., fortified residences of local elites often used for administration including taxation) to (generally) shore up their vulnerabilities and (specifically) as a vital defence against their nearby peers, in a context where land is wealth and the central state isn't powerful enough to police them.

Castles exist in those conditions as long as there are the resources to make them, and as long as there aren't technologies that can trivially defeat them. Note that castles were replaced by star fortresses in the era of powerful artillery. Lots of common fantastic elements can defeat stone walls at a distance or under cover of stealth: flight or levitation, rock-to-mud or other transmutations, giants or other really big creatures, instantaneous travel, earthquakes, and powered-up versions of mundane siege attacks, like tunnelling, throwing big rocks, or inflicting plague or demoralisation. Such elements entail fewer castles - or none, if they are sufficiently available. Maybe star forts are the way to go in this particular fantasy setting. Or bunkers. Or enormous moats. Or maybe magic is the only defence that works.

Of course, if fantastic elements make it easier to build castles, that provides an impetus in the opposite direction. If good permanent masonry can be conjured by any town magician, then yes, castles might be everywhere despite being permeable to magic... but also, every town will be furnished with multiple curtain walls, aqueducts, tall stone buildings, stone roads, and so on.

In general, every fantastic element in a setting needs to be considered in terms of: how does this affect the overall milieu? If every other mage can send a magical message a hundred miles and every town has at least a couple of mages, what does that imply for a ruler's ability to receive information, wage war, and administer the state at a distance? Because it's sure not governed by the speed of a messenger on horseback any more.

Category 3. Assumptions Based on Modern Culture.

Writers all too often take for granted that some aspects of a free, capitalist society will just show up in a setting: a cash economy, an absence of individual obligations to people higher in the pecking order (or a lack of a pecking order), freedoms of speech and movement and so on, and a modern sense of morality where things like 'don't torture animals' and 'don't execute prisoners' are obvious rather than a weird joke.

Obviously some of these things are desirable to have in a setting just so that readers or players won't be icked out. And obviously if a game or novel requires its audience to pursue a comprehensive course of historical/sociological/economic study before they can engage with it, that game or novel is limiting itself in a pretty major way. But if a setting has these things, it should have a reason to have them. It's not actually that difficult to do - 'gods literally exist, they desire these things for a reason X, and they have worked to implement them by means Y' gets you most of the way there in one sentence. Our peeve is when the world is 'modern Western civilisation with the serial numbers written in Blackletter' and that's just ...how it is. The average powerless pre-industrial commoner can go where they want, choose where to work, says what they want to who they want, has money and spends it, doesn't live in fear of the powerful, and is a devout utilitarian ethicist. Without any of the necessary structures to enable that.

Category 4. Maladaptive Feedback Loops.

There's something that's happened since the dawn of TTRPGs. Game masters - or players - excise the parts of the rules they don't like or don't see the need for. The least popular rules get ignored, popular house-rules spring up and pass on, and in the worst case, poorly-laid-out rule books result in certain good ideas just never making it to the table. Popular voices spread their own gameplay changes through the hobby - first through magazines, then blogs, now social media - and widespread changes in gameplay result.

Later generations of designers create new editions of old games, or make their own new games, based on the way they remember playing or the way people seem to want to play. The feedback loop completes. Some innovations are for the better, but useful material is also lost.

And so you get big successful games about delving into dungeons with whole books oriented towards game masters which somehow forget to teach said game masters how to properly run a dungeon delve. Or sections on realm management which boil down to 'wing it', where bygone editions had exceptional rules for that baked in. Or wilderness survival rules so brief and generous that choosing the right starting character negates any possible wilderness survival gameplay.

Well, so what?

In our own work, we like to put together material that bears all these things in mind. We said 'peeves', but really, it's about forming a cohesive, interesting whole that won't turn off a reader who knows too much and doesn't expect too much out of a new reader/player who's coming from a different genre, style, or expectation.