Hard Fantasy

[Satinavian]

Oh, i actually like the books. He has good characters and good conflicts. I always hated that "fantasy" meant the most simplicistic plot and most one-dimensional shallow characters because people didn't see it as a serious genre and therefore underestimated the audience.

But he also has some major weaknesses as author and numbers is one of them.

[PhoenixPhyre]

A related issue of worldbuilding where I see a difference between sci-fi and fantasy is that of choosing a starting point.

There are two extremes:
1) Forward extrapolation from real life. This style starts with a fixed baseline (real life) and asks "what happens if we change X." Alternate histories are commonly written from this perspective. For example, "what happens if the American Revolution failed?" or "what happens if gunpowder wasn't perfected when it was?". Near-future sci-fi often takes this approach to one degree or another.
** Advantages: a fixed, relatively well-known starting point and a consistent set of operating principles. Probably easier to research and make consistent (as long as the changes or time scale is short enough)--you don't have to redo as much.
** Disadvantages: Higher verisimilitude requirement. Your historiography and cultural data better be good. Exponentially compounding (and interrelated) causation makes distant extrapolations difficult (if you want to maintain consistency). If portrayed wrong, can bloat the setting or story with a bunch of "useless" facts and get in the way of the story/game-play.

2) Backward extrapolation from a desired end goal. This style starts with the end ("I want medieval-ish fantasy with dragons") and works backward to decide what the physical, magical, cultural and other parameters must have been to bring about the end goal. This is common in "hard" fantasy and a lot of sci-fi.
** Advantages: No restriction to "actual" history--you can pick and choose how things happened to guide history to your desired goal. This often leads to "convenient" histories, where everything is set up so that the events of the plot come about. Greenfield design makes it easier to adjust parameters as needed.
** Disadvantages: Often comes across as artificial or forced (even if there's a good logical chain from first cause to effect). Often produces a surface consistency that falls apart once you start digging (because the author only went so far in smoothing things out. Lends itself to being "soft" (ignoring inconvenient facts to make sure the desired story gets told).

Most fiction is probably a mix of the two (or just entirely hand-waved, which is style 2 without the extrapolation). Neither is bad, neither is good. But they're very different styles. You can do "hard" in either style, you can do "soft" in either style. But they have their advantages and disadvantages.

[Max_Killjoy]

A related issue of worldbuilding where I see a difference between sci-fi and fantasy is that of choosing a starting point.

There are two extremes:
1) Forward extrapolation from real life. This style starts with a fixed baseline (real life) and asks "what happens if we change X." Alternate histories are commonly written from this perspective. For example, "what happens if the American Revolution failed?" or "what happens if gunpowder wasn't perfected when it was?". Near-future sci-fi often takes this approach to one degree or another.
** Advantages: a fixed, relatively well-known starting point and a consistent set of operating principles. Probably easier to research and make consistent (as long as the changes or time scale is short enough)--you don't have to redo as much.
** Disadvantages: Higher verisimilitude requirement. Your historiography and cultural data better be good. Exponentially compounding (and interrelated) causation makes distant extrapolations difficult (if you want to maintain consistency). If portrayed wrong, can bloat the setting or story with a bunch of "useless" facts and get in the way of the story/game-play.

2) Backward extrapolation from a desired end goal. This style starts with the end ("I want medieval-ish fantasy with dragons") and works backward to decide what the physical, magical, cultural and other parameters must have been to bring about the end goal. This is common in "hard" fantasy and a lot of sci-fi.
** Advantages: No restriction to "actual" history--you can pick and choose how things happened to guide history to your desired goal. This often leads to "convenient" histories, where everything is set up so that the events of the plot come about. Greenfield design makes it easier to adjust parameters as needed.
** Disadvantages: Often comes across as artificial or forced (even if there's a good logical chain from first cause to effect). Often produces a surface consistency that falls apart once you start digging (because the author only went so far in smoothing things out. Lends itself to being "soft" (ignoring inconvenient facts to make sure the desired story gets told).

Most fiction is probably a mix of the two (or just entirely hand-waved, which is style 2 without the extrapolation). Neither is bad, neither is good. But they're very different styles. You can do "hard" in either style, you can do "soft" in either style. But they have their advantages and disadvantages.

Both of my fantasy settings are a combination of both -- working in both directions at once -- although the "forward extrapolation" isn't strictly from the real world, but from the elements I want to use and the starting conditions that I think will get me to where I want to go and that, honestly, just sounded interesting to me.

Maybe I come across as demanding a strict "work forward" approach, but that's not my intent. The point isn't the particular process, the point is to have a process. I'm trying hard to not be "judgey" about Kitchen Sink Settings because I don't want to fall into the "badwrongfun" trap... but they really do strike me as just throwing stuff in because it looks cool and not caring if it makes any sense.

[PhoenixPhyre]

Both of my fantasy settings are a combination of both -- working in both directions at once -- although the "forward extrapolation" isn't strictly from the real world, but from the elements I want to use and the starting conditions that I think will get me to where I want to go and that, honestly, just sounded interesting to me.

Maybe I come across as demanding a strict "work forward" approach, but that's not my intent. The point isn't the particular process, the point is to have a process. I'm trying hard to not be "judgey" about Kitchen Sink Settings because I don't want to fall into the "badwrongfun" trap... but they really do strike me as just throwing stuff in because it looks cool and not caring if it makes any sense.

And I probably came across more judgy than I meant to. It was more a musing on a related (but largely orthogonal) issue. I do think that "makes sense" (in this context) is not an objective measure. It strongly depends on the person (and their frame of reference). Heck--there are lots of things in real life that don't "make sense", although I'm sure that causality is maintained throughout and everything's consistent. That's what happens when you have very large, complex, strongly interacting systems.

[Max_Killjoy]

And I probably came across more judgy than I meant to. It was more a musing on a related (but largely orthogonal) issue. I do think that "makes sense" (in this context) is not an objective measure. It strongly depends on the person (and their frame of reference). Heck--there are lots of things in real life that don't "make sense", although I'm sure that causality is maintained throughout and everything's consistent. That's what happens when you have very large, complex, strongly interacting systems.

"Doesn't make sense" can be as simple as the classic example from "default quasi-medieval" D&D-like fantasy settings. Here's a setting CHOCK FULL of flying armored fire-breathing spell-casting beings (dragons, wizards, extraplanar whatnots, etc, etc, etc), massive damage spells, invisibility, teleportation, and other fantastic threats. But... it also has stereotypical castles and fortresses copied right out of real-life Europe, which appear to have been built with ZERO regard for those other elements of the setting.

Some proponents of those settings go down a rabbit-hole of increasingly convoluted justifications.

Others just say "dragons are cool, wizards are cool, castles are cool, it's fantasy and you're being a nerd".

[kyoryu]

Some proponents of those settings go down a rabbit-hole of increasingly convoluted justifications.

Others just say "dragons are cool, wizards are cool, castles are cool, it's fantasy and you're being a nerd".

If you're gonna go kitchen sink, I'd go with the latter, because, well, it's the truth. I may not say "you're being a nerd", though.

I mean, really, that's the goal is to have these cool things in there, so go with that. Own it. Cool stuff is the primary goal, plausibility is secondary.

[Aliquid]

"Doesn't make sense" can be as simple as the classic example from "default quasi-medieval" D&D-like fantasy settings. Here's a setting CHOCK FULL of flying armored fire-breathing spell-casting beings (dragons, wizards, extraplanar whatnots, etc, etc, etc), massive damage spells, invisibility, teleportation, and other fantastic threats. But... it also has stereotypical castles and fortresses copied right out of real-life Europe, which appear to have been built with ZERO regard for those other elements of the setting.

Some proponents of those settings go down a rabbit-hole of increasingly convoluted justifications.

Others just say "dragons are cool, wizards are cool, castles are cool, it's fantasy and you're being a nerd".

When it comes down to it, I'm really conflicted on this whole subject. I find it hard to immerse myself in a world without effort being put into these things. So, for the dragon example, I don't even want convoluted justifications, I want the castles replaced with something else... or castles with modifications to address the new threats.

BUT... a DM, or author can't think of everything, and they aren't an expert in everything. They could make a world that makes sense from their perspective, and then I look at the world map and say "it would be impossible for there to be a desert at that location, and that mountain range makes no sense." Then the author will have to be able to explain why his world has different geomorphological and climatological rules, and what those rules are.

I can't even say "well at least put an effort into it and deal with the obvious implications of being in a fantasy world where ___ exists". What is obvious to me is very different from what is obvious to the next person.

[Max_Killjoy]

When it comes down to it, I'm really conflicted on this whole subject. I find it hard to immerse myself in a world without effort being put into these things. So, for the dragon example, I don't even want convoluted justifications, I want the castles replaced with something else... or castles with modifications to address the new threats.

BUT... a DM, or author can't think of everything, and they aren't an expert in everything. They could make a world that makes sense from their perspective, and then I look at the world map and say "it would be impossible for there to be a desert at that location, and that mountain range makes no sense." Then the author will have to be able to explain why his world has different geomorphological and climatological rules, and what those rules are.

I can't even say "well at least put an effort into it and deal with the obvious implications of being in a fantasy world where ___ exists". What is obvious to me is very different from what is obvious to the next person.

I do that thing with maps, too, looking at the climatology and geology and such.

And history... and politics... and religion... and warfare & weapons & armor... and economics... and cultures... and yeah...

It's a good thing I enjoy worldbuilding, because it's not easy.

[Aliquid]

I do that thing with maps, too, looking at the climatology and geology and such.

And history... and politics... and religion... and warfare & weapons & armor... and economics... and cultures... and yeah...

It's a good thing I enjoy worldbuilding, because it's not easy.

I am able to put aside many geographical errors when looking at maps, and just say to myself that the fantasy world has different rules... but there are things I can't let slide, like "Hey... you know that map of your world? Look at that river. It would have to run uphill at some point to get to that destination."

[Max_Killjoy]

I am able to put aside many geographical errors when looking at maps, and just say to myself that the fantasy world has different rules... but there are things I can't let slide, like "Hey... you know that map of your world? Look at that river. It would have to run uphill at some point to get to that destination."

If a setting apparently has different rules, then I start looking at where those other rules would apply, and if it's not consistent and coherent, then I figure that it's not a matter of different rules, it's a matter of bad worldbuilding or an author who simply didn't give a... dang.

[Yora]

Eh, that map probably isn't very accurate anyway.

Which is why I really don't like modern maps that look like satelite images. Fantasy maps are for orientation to understand what's going on, not for geographic and geologic surveys.

When it comes to fantastic elements, I am always much more interested in the exotic than the rules rewriting. My monsters tend to be mostly fictional animals and the supernatural creatures have very limited powers and are very rare. A castle not being dragon proof is not a problem when dragon attacks are not something that is reasonably expected to happen. My magic leans heavily to hints and deception rather than instant knowledge and instant free access. I don't really do battle magic at all.

That's one of the main reasons I have stopped running games with D&D rules... it is too hard to run a "hard fantasy" game in D&D without making major changes.

At some point early into AD&D, D&D became something that is really only good at running D&D settings.

[Max_Killjoy]

Eh, that map probably isn't very accurate anyway.

Which is why I really don't like modern maps that look like satelite images. Fantasy maps are for orientation to understand what's going on, not for geographic and geologic surveys.

When it comes to fantastic elements, I am always much more interested in the exotic than the rules rewriting. My monsters tend to be mostly fictional animals and the supernatural creatures have very limited powers and are very rare. A castle not being dragon proof is not a problem when dragon attacks are not something that is reasonably expected to happen. My magic leans heavily to hints and deception rather than instant knowledge and instant free access. I don't really do battle magic at all.

If dragons are something that happen multiple generations and 100s of miles apart, then castles being more historical-like isn't that big a deal... but the general D&D setting seems to be rife with dragons and other flying, death-spewing threats.

At some point early into AD&D, D&D became something that is really only good at running D&D settings.

Yeap.

[PhoenixPhyre]

If dragons are something that happen multiple generations and 100s of miles apart, then castles being more historical-like isn't that big a deal... but the general D&D setting seems to be rife with dragons and other flying, death-spewing threats.

I think that's partly due to seeing things through the lens of PCs (or fantasy protagonists generally). They're not a random sample--we don't play the game of "farmer who never saw anything." We play as heroes doing heroic things. Seeking out danger. In many settings, things like dragons and high magic are rare. The exception really (like in many things) was 3e--the demographic tables were all screwy and had way too many high level people in general. But that whole edition was wack.

At least in my setting, things like hostile dragons are legends. Dragons aren't--there's one the claims a city as her hoard (but the worst she ever did is kidnap people to tell her stories. And then pay them well). Until recently, monsters were things that existed "out there", beyond the safe walls.

[CharonsHelper]

The exception really (like in many things) was 3e--the demographic tables were all screwy and had way too many high level people in general.

Forgotten Realms had scads of higher level adventurers every which way well before 3e.

[Max_Killjoy]

In terms of being persons who inhabit their world, I don't really buy into PCs being special exceptions (exceptional yes, rare yes... exceptions no) where each group of PCs is treated as if they're the only group of special chosen unique powerhouses of their century or whatever. The idea that each group of PCs is yet another special bunch of unmatched paragons... no. That might work in authorial fiction, but it wears thin in a game setting.

If PC Bob can become a high-level fighter or spellcaster or cleric, than so can some NPCs.

What the PCs can do tells us something about the world they inhabit and what's possible there. If the PCs are fighting dragons, that means there are dragons to fight.

[PhoenixPhyre]

In terms of being persons who inhabit their world, I don't really buy into PCs being special exceptions (exceptional yes, rare yes... exceptions no) where each group of PCs is treated as if they're the only group of special chosen unique powerhouses of their century or whatever. The idea that each group of PCs is yet another special bunch of unmatched paragons... no. That might work in authorial fiction, but it wears thin in a game setting.

If PC Bob can become a high-level fighter or spellcaster or cleric, than so can some NPCs.

What the PCs can do tells us something about the world they inhabit and what's possible there. If the PCs are fighting dragons, that means there are dragons to fight.

But they're exceptional by their nature. Out of the many adventurers that start off, they survived. It's survivorship bias. Also, the tables are way off as to how many reach those levels. Yes, pre-3e FR had lots of high-level ex-adventurers walking around, but they were a drop in the bucket. It seems that you'd run into them a lot, but that's a narrative, rather than in-fiction thing. As a proportion of the population, those ex-adventurers were indistinguishable from zero. The PCs aren't destined heroes, but they're rare. We follow their story because it's maximally interesting. We don't hear about the many adventurers who either died to wolves on their first adventure or never saw anything more than goblins in the woods. Because those are boring.

3e altered this (as I understand it) and gave a breakdown of how many NPCs of which levels (and classes) you'd have in a given average town. And ended up with absurd (to me at least) numbers. This was a consequence of forcing NPCs to run on the same set of class/level restrictions as PCs (especially where skills are concerned). If the king (to be able to persuade people to follow him) had to be level X (something pretty high) and the priest had to have Y levels in Cleric to ask for miracles, you end up with a screwy distribution.

4e and 5e went away from this by making it clear that classes and levels (and the attendant baggage) are purely game conceits--they're simply a UI that allows a simple way of allocating powers and stats. In-universe, only a rare few priests are Clerics (or can cast spells at will at all instead of being granted miracles at the will of their deity). Personally, I strongly prefer this way, both from a world-building perspective and a game-running perspective. The rules exist to deal with interactions between PCs and their environment, including the NPCs, in a way that we can use to play a game. That's all. They are simplifications and abstractions of the real thing, sure, but shouldn't be taken too seriously as an actual window into the fictional universe's behavior. That comes from the fictional side of things, not the rule side of things.

[CharonsHelper]

4e and 5e went away from this by making it clear that classes and levels (and the attendant baggage) are purely game conceits--they're simply a UI that allows a simple way of allocating powers and stats.

Actually - even in 3.5, Eberron considerably lowered average level relative to 3.x in general, though they still had kings etc. with a good chunk of levels.

[PhoenixPhyre]

Actually - even in 3.5, Eberron considerably lowered average level relative to 3.x in general, though they still had kings etc. with a good chunk of levels.

And that was a good thing. IIRC, a lot of that came from using NPC classes with strongly restricted power instead of FR's habit of using PC class levels for NPCs.

Currently I'm working on a power-level-equivalent breakdown for the core nations of my setting. My most populous nation (at about 300k people spread out over something roughly the same area as New York State, with 20k in the capital) has about 10 people capable of casting 9th level spells. 3 bards (one former character made ageless, and two of his descendants; the dude is responsible for something like 25% of the half-elves of the nation ), 3 clerics (One each of Justice, Winter/Death, and Summer/Sun/Strength), 2 wizards, and 2 others. Lots of people (~10% of the population) can work ritual spells, but can't cast spells from slots. Another 10% can cast 1st level spells, and the numbers plummet from there.

When the PCs retire (if they actually do), they'll represent a full 29% of the high-power-level people in the entire nation. That's ok--they did their adventuring elsewhere. Outside of settled lands. Against foes that were either ancient, planar, or both.

[Aliquid]

In terms of being persons who inhabit their world, I don't really buy into PCs being special exceptions (exceptional yes, rare yes... exceptions no) where each group of PCs is treated as if they're the only group of special chosen unique powerhouses of their century or whatever. The idea that each group of PCs is yet another special bunch of unmatched paragons... no. That might work in authorial fiction, but it wears thin in a game setting.

If PC Bob can become a high-level fighter or spellcaster or cleric, than so can some NPCs.

What the PCs can do tells us something about the world they inhabit and what's possible there. If the PCs are fighting dragons, that means there are dragons to fight.

I'm running a game (not D&D, but a fantasy world), with some kids new to the game. I've made a point of having them run into other NPC adventurers (especially in highly populated areas), and witness the Duke give awards to people other than just them for heroic acts to help the city.

At one point while they were sneaking across town over the rooftops at night, they witnessed a pair of adventurers hunting werewolves. I expected the players to jump in and help, but they decided to just watch briefly and move on. "not our problem, we got other things to deal with". There was also a time where monsters were streaming out of a building and the PCs heard the cries for help, so ran to assist. Some other NPC adventurers joined in the fight right near then end of the battle and then tried to take all the credit. Now that really pissed off one of the players, her character went full out ballistic on the NPC (verbally).

[RazorChain]

But they're exceptional by their nature. Out of the many adventurers that start off, they survived. It's survivorship bias. Also, the tables are way off as to how many reach those levels. Yes, pre-3e FR had lots of high-level ex-adventurers walking around, but they were a drop in the bucket. It seems that you'd run into them a lot, but that's a narrative, rather than in-fiction thing. As a proportion of the population, those ex-adventurers were indistinguishable from zero. The PCs aren't destined heroes, but they're rare. We follow their story because it's maximally interesting. We don't hear about the many adventurers who either died to wolves on their first adventure or never saw anything more than goblins in the woods. Because those are boring.

3e altered this (as I understand it) and gave a breakdown of how many NPCs of which levels (and classes) you'd have in a given average town. And ended up with absurd (to me at least) numbers. This was a consequence of forcing NPCs to run on the same set of class/level restrictions as PCs (especially where skills are concerned). If the king (to be able to persuade people to follow him) had to be level X (something pretty high) and the priest had to have Y levels in Cleric to ask for miracles, you end up with a screwy distribution.

4e and 5e went away from this by making it clear that classes and levels (and the attendant baggage) are purely game conceits--they're simply a UI that allows a simple way of allocating powers and stats. In-universe, only a rare few priests are Clerics (or can cast spells at will at all instead of being granted miracles at the will of their deity). Personally, I strongly prefer this way, both from a world-building perspective and a game-running perspective. The rules exist to deal with interactions between PCs and their environment, including the NPCs, in a way that we can use to play a game. That's all. They are simplifications and abstractions of the real thing, sure, but shouldn't be taken too seriously as an actual window into the fictional universe's behavior. That comes from the fictional side of things, not the rule side of things.

You are looking at this through D&D lenses. When I'm world building the mechanics come second. If the mechanics can't support the world then I need new mechanics. The problem is that the creators of D&D have published worlds that aren't supported with the mechanics and they are bound by said mechanics whereas I aren't.

So in D&D land when that soldier in the castle is manning the ballista cannot hit the dragon because of the mechanics unless he's high enough level or it's a +5 Ballista. This is when the mechanics and the world starts to clash. In another system there might be a ballista skill and I can just reasonably assume that the soldier manning the ballista has trained using it else he wouldn't be manning the ballista.

So if we start to look at level spread, let's not even go the way that there is a level 1 guy for every ten 0 level guys. Let's just say for every two 0 level guys there is a level 1 guy and etc.

20th level : 1
19th level : 2
18th level : 4
17th level : 8
16th level : 16
15th level : 32
14th level : 64
13th level : 128
12th level : 256
11th level : 512
10th level : 1024
9th level : 2048
8th level : 4096
7th level : 8192
6th level : 16384
5th level : 32768
4th level : 65536
3rd level : 131072
2nd level : 262144
1st level : 524288
0 level : 1048576

So here you have one 20th level character for every 2.2 million people/creature/whatever. If you want to stretch this to 1 in 5 then you have a 20th level character for every 100+ million people and god forbid if you stretch this to 1 in 10 ration because then you have a 20th level guy for billions upon billions of people.

So when your character walks into Mudtown with the population of 1300 then even if we go for the 1 in 5 then there should at least be around two 4th level guys, ten 3rd level guys, fifty 2nd level guys and two hundred and fifty 1st level guys.

So the question is how many adventurers have to die for one to reach level 20?

[PhoenixPhyre]

Spoiler: RazorChain

Show

You are looking at this through D&D lenses. When I'm world building the mechanics come second. If the mechanics can't support the world then I need new mechanics. The problem is that the creators of D&D have published worlds that aren't supported with the mechanics and they are bound by said mechanics whereas I aren't.

So in D&D land when that soldier in the castle is manning the ballista cannot hit the dragon because of the mechanics unless he's high enough level or it's a +5 Ballista. This is when the mechanics and the world starts to clash. In another system there might be a ballista skill and I can just reasonably assume that the soldier manning the ballista has trained using it else he wouldn't be manning the ballista.

So if we start to look at level spread, let's not even go the way that there is a level 1 guy for every ten 0 level guys. Let's just say for every two 0 level guys there is a level 1 guy and etc.

20th level : 1
19th level : 2
18th level : 4
17th level : 8
16th level : 16
15th level : 32
14th level : 64
13th level : 128
12th level : 256
11th level : 512
10th level : 1024
9th level : 2048
8th level : 4096
7th level : 8192
6th level : 16384
5th level : 32768
4th level : 65536
3rd level : 131072
2nd level : 262144
1st level : 524288
0 level : 1048576

So here you have one 20th level character for every 2.2 million people/creature/whatever. If you want to stretch this to 1 in 5 then you have a 20th level character for every 100+ million people and god forbid if you stretch this to 1 in 10 ration because then you have a 20th level guy for billions upon billions of people.

So when your character walks into Mudtown with the population of 1300 then even if we go for the 1 in 5 then there should at least be around two 4th level guys, ten 3rd level guys, fifty 2nd level guys and two hundred and fifty 1st level guys.

So the question is how many adventurers have to die for one to reach level 20?

So in D&D land when that soldier in the castle is manning the ballista cannot hit the dragon because of the mechanics unless he's high enough level or it's a +5 Ballista. This is when the mechanics and the world starts to clash. In another system there might be a ballista skill and I can just reasonably assume that the soldier manning the ballista has trained using it else he wouldn't be manning the ballista.

This right here is where the mechanics go sideways and the cause of all the screwy results. It makes levels an actual thing in-universe and forces a particular distribution of power levels that has far-reaching results. I play 5e, where this assumption is not in play. Bounded accuracy takes care of that--even a bunch of CR 1/8 guards with bows can be a serious threat to a dragon, and the ballista uses its own stats.

Spoiler: Assumptions for my setting

Show

I'm currently (as in, on the other screen as I type this) working through the spell-casting capability matrix for some of my cultures. These aren't class levels, but more "can cast the same levels of spells as a X of level Y." My working assumptions are as follows:

* Zero level casting (rituals + cantrips) are relatively easy to acquire.
* First level casting (magic initiate, racial casting, or the equivalent) is about as common.
* Magic comes in tiers: level 0, levels 1-2, 3-5, 6-8, and 9. Moving within a tier is easy, moving between tiers represents a big leap. This comes from the observed power of spells--2nd level are ~ 1st level, 3rd are a lot bigger, 6th are a lot bigger than 5th, and 9th are huge compared to 8th.

This leads to the following breakdown:

Highest Spell Slot	Weight
9	1
8	10
7	20
6	40
5	400
4	800
3	1600
2	16000
1	32000
0	32000

This leaves my bigger base nations with ~1 person that can cast 9th level spells. This varies a bit, because I take race into account as well, but...
About 30% can cast spells over all, with 22% restricted to level 1 or 0 casting. I'm still tweaking the numbers, but I think it looks reasonable so far.

No NPCs has PC class levels--those only exist for PCs. They may cast similar spells in similar ways (to save my sanity, if nothing else), but they're not Clerics, or Paladins. They're acolytes, priests, or zealots. The idea that classes and levels (and XP) are an in-universe reality annoys me. It's turning a UI convention into a physical reality.

Edit: And to answer the question--in canon history there have been no adventurers who reached level 20. The group who is highest (level 17 right now) stopped adventuring and settled down at level ~10 in the canon timeline. There are people who (for example) cast 9th level spells, but they aren't adventurers and don't have the class features, etc of PCs.

[Aliquid]

So the question is how many adventurers have to die for one to reach level 20?

Well, they don't all have to die.
- Some might make it to level 3 and suffer from so much PTSD that they have no interest in continuing.
- Some might make it to level 5 and realize they have enough money to buy a little place on the countryside and retire
etc.

[PhoenixPhyre]

Well, they don't all have to die.
- Some might make it to level 3 and suffer from so much PTSD that they have no interest in continuing.
- Some might make it to level 5 and realize they have enough money to buy a little place on the countryside and retire
etc.

This. Or they may cap out. Outside of 3.X, there's no indication that all people (PCs aside) can reach all power levels. I tend to do it by tiers--lots can't even get to level 1, most of those can't get beyond level 4, very few to level 11, a tiny fraction to level 17, and an infinitesimal amount to level 20. We just watch PCs because they're some of the rare few who (if the campaign gets that far) could in theory get to 20. Who knows, if they retire at level X, they may have capped (in-universe) at level X+1, or maybe had no cap. Without adventuring, levels don't increase. Power can (boons, political status, etc), but not PC class levels.

[Segev]

I often enjoy the "Work backwards" approach. And then working back forwards to see what the things I've explained would still change in the setting.

One easy-ish approach to justifying European castles is "dragons and wizards and the like are rare and usually aren't attacking castles." The keep of a dragonslayer may well look exotic and different to deal with its higher probability of encountering the targets of its master's profession.

[Max_Killjoy]

This. Or they may cap out. Outside of 3.X, there's no indication that all people (PCs aside) can reach all power levels. I tend to do it by tiers--lots can't even get to level 1, most of those can't get beyond level 4, very few to level 11, a tiny fraction to level 17, and an infinitesimal amount to level 20. We just watch PCs because they're some of the rare few who (if the campaign gets that far) could in theory get to 20. Who knows, if they retire at level X, they may have capped (in-universe) at level X+1, or maybe had no cap. Without adventuring, levels don't increase. Power can (boons, political status, etc), but not PC class levels.

To me this is a bit like having a game with a modern-day setting and saying that only the PCs can get doctorates, and all NPCs are confined to high school education or at best a bachelor's for a few of them.

[CharonsHelper]

To me this is a bit like having a game with a modern-day setting and saying that only the PCs can get doctorates, and all NPCs are confined to high school education or at best a bachelor's for a few of them.

I'd argue it's more like having a game where PCs are scientists allowing anyone to go to college, but PCs are the ones playing Einstein style characters making all of the groundbreaking discoveries. Sure - anyone can research, but even of those only a small % of those (relatively rare) scientists are going to make those breakthroughs.

[Mr Beer]

To me this is a bit like having a game with a modern-day setting and saying that only the PCs can get doctorates, and all NPCs are confined to high school education or at best a bachelor's for a few of them.

"PCs are different and special" is a feature rather than a bug IMO. I don't run games where only PCs can level up but I don't hate the notion. I wouldn't consider it to be typical of a "hard fantasy" setting though.

[SleeplessWriter]

As a science fiction and fantasy writer and enthusiast, I love the idea of Hard Fantasy. Much of that comes from the fact that when making a fantasy world I often like to approach it with methods from from science fiction, and treat magic as much like a set of physics, or at least something with consistent enough rules and tendencies. As for the genre debate, all I'm going to say is that academics and writers have gone through the whole science fiction versus fantasy debate, and so far all that's concretely come out of that is people getting tired of the whole affair and tossing the two into the overgenre Speculative Fiction; and as for Anthropologically Rigorous Fantasy, that sounds less like a genre, and more like a goal.
As a cousin and a counterpoint to Hard Sci-Fi, Hard Fantasy seems, at least to me, to say, "If Hard Sci-Fi gets its FTL, then I can get my magic." (Other people most likely have a different view, since genres are culturally and individually defined, which is the main cause of said headache inducing debates. Even if they're interesting, they can get out of hand real fast.)
In short, what I'm saying is that Hard Fantasy lets you use the tools from science fiction for the fantasy genre in much the same way that Hard Fantasy lets you strip away many of the extra expectations, cliches, and assumptions of the science fiction genre (e.g. blasters, instantaneous communication, always humanoid aliens, etc.). In essence, they both let you strip away many of the more frivolous and unrealistic elements that are often expected of the genre, and they both give the worldbuilder a certain mindset about what is, and isn't, possible in their world.
(Side note: I also like Speculative Fiction because it lets you get away from the binary of science fiction and fantasy, and instead lets you use tools from the two simultaneously.)