D&D 5E Proposed rule for number of character-class-equivalent NPCs in a D&D world

[clearstream]

We had a good discussion in a thread about how many adventurers there are in people's D&D worlds. From that I'd like to propose the following simplified rule of thumb.

About 1/100 people have tier 1 character class-equivalence, with an order of magnitude fewer per tier above that. An Intelligence (Investigation) ability check DC 5*Tier can discover the whereabouts of such an NPC so long as they are not taking steps to avoid being found; add 5 to that DC if the search is conducted in a settlement with fewer than 10,000 inhabitants. Triple the tier counts and subtract 5 from the DC if the region is on a war footing. Monster Manual stat blocks such as the Mage represent such NPCs in abstract, and are usually sufficient to run them: adding more detail using their character class where required. Their Hit Dice indicates their tier.

What are the goals here?

1. Fast to use without needing a spreadsheet or a table
2. Consistent, so it helps sustain a credible game world (Tolkien's principle)
3. Passes the test of roughly yielding the D&D baseline world (Faerun)
4. Flexible, so it accommodates DMs without their needing to constantly break from it
5. Accurate, rather than precise: it guides, rather than dictates
6. Gives a quick and consistent DC for when PCs want to find an NPC (e.g. for training)

So if my town has 6700 inhabitants I know immediately that there could be about 67 tier 1 NPCs and 6-7 tier 2, and probably no more than 1 tier 3. If my PCs need to find that one tier 3, they'll have a DC 20 check to make. It's nearly impossible to find an Epic level NPC in such a town. If I decided to allow my PCs to try to track one down, that would be a DC of 30.

 

[Quickleaf]

We had a good discussion in a thread about how many adventurers there are in people's D&D worlds. From that I'd like to propose the following simplified rule of thumb.

About 1/100 people have tier 1 character class-equivalence, with an order of magnitude fewer per tier above that. An Intelligence (Investigation) ability check DC 5*Tier can discover the whereabouts of such an NPC so long as they are not taking steps to avoid being found; add 5 to that DC if the search is conducted in a settlement with fewer than 10,000 inhabitants. Monster Manual stat blocks such as the Mage represent such NPCs in abstract, and are usually sufficient to run them: adding more detail using their character class where required.

What are the goals here?

1. Fast to use without needing a spreadsheet or a table
2. Consistent, so it helps sustain a credible game world (Tolkien's principle)
3. Passes the test of roughly yielding the D&D baseline world (Faerun)
4. Flexible, so it accommodates DMs without their needing to constantly break from it
5. Accurate, rather than precise: it guides, rather than dictates
6. Gives a quick and consistent DC for when PCs want to find an NPC (e.g. for training)

So if my town has 6700 inhabitants I know immediately that there could be about 67 tier 1 NPCs and 6-7 tier 2, and probably no more than 1 tier 3. If my PCs need to find that one tier 3, they'll have a DC 20 check to make. It's nearly impossible to find an Epic level NPC in such a town. If I decided to allow my PCs to try to track one down, that would be a DC of 30.

Schrödinger's NPCs? It's a clean system, with just one quirk. You'd figure in a town of 6700 that pretty much everyone is going to have heard of that 11th-16th level witch kicking around. But your system presents exactly the opposite.

 

[S'mon]

Yup, as I said in the other thread, when I compiled the number of Tier II+ NPCs in the most detailed part of my Wilderlands sandbox, having 1% of NPCs Tier 1, and 1/10 per higher Tier, looks dead on. So in an area of 100,000 NPCs you get 1000 Tier I, 100 Tier II, 10 Tier III and 1 Tier IV.

I think the formula works best for adventure-heavy areas such as borderlands, points of light, and large cities - the kind of places PCs gravitate to.

I think vast swathes of agricultural territory will have lower concentrations of powerful NPCs - eg a large agricultural kingdom of 25 million resembling medieval France probably should have about an order of magnitude fewer Tiered (CR 1+, or PC-equivalent) NPCs overall, with concentrations in the capital city, major regional cities, and in the borderlands.

That would give:
25 million people
25,000 Tier I (0.1%)
2,500 Tier II
250 Tier III
25 Tier IV

I think that works for something like Greyhawk's Great Kingdom, a Roman Empire analogue like Mystara's Thyatis, or Mystara's Alphatian Empire (Alphatia that is noted as having a Grand Council of 1000 Wizards - I'd probably give them 1000 Wiz 11+ in 5e, most would be Tier II in CR power terms).

A notably vast and peaceful realm might have another order of magnitude fewer Tiered NPCs, eg if I want to threaten my 100 million population China analogue with barbarian invaders I might give them

100 million people
10000 Tier I (0.01%)
1000 Tier II
100 Tier III
10 Tier IV

Or I might say they still had plenty Tier 1 types, but frequency fell off much faster at higher Tiers.

Yet still, in the borderland regions or imperial capital, where the PCs are most likely found, the distribution will still resemble 1%/0.1%/0.01% etc - so I think it's a very handy rule of thumb at ground level.

 

[cbwjm]

I'd have thought that the more powerful would have greater notoriety and therefore be easier to find. Everyone knows of the high priest that called down heavenly assistance or the secretive mage hiding in his tower but maybe not everyone knows the whereabouts of a 2nd level ranger that your group wants to hire.

 

[clearstream]

Schrödinger's NPCs? It's a clean system, with just one quirk. You'd figure in a town of 6700 that pretty much everyone is going to have heard of that 11th-16th level witch kicking around. But your system presents exactly the opposite.

That's a very good point! For towns below 10,000 population, there is <100% chance of a tier 3 NPC kicking around. So the DC in effect tests that chance. If failed, it is not that they are swanning up the main street and the PCs failed to spot them. It is that they turn out not to be present. Schrödinger's NPCs as you say One could be more precise, but perhaps at the cost of streamlining?

The character sought may be unlikely to exist, or if they exist they might be away, or if they are at home they might not announce that fact, or if they do announce their presence they might resist contact, or if they accept contact they might turn out to be a Warlock and not the high-level Cleric my PCs were looking for. So there are a few possible outs. Are they satisfactory, or can you think of a way to improve on it?

 

[Mephista]

Why do you feel the need for a rule in the first place? Curious minds inquiring. Aren't the needs of the towns and cities dictated by your current story? About what feels right to your players' perceptions?

 

[BoldItalic]

The model is making hidden assumptions about the statistical distribution of settlement sizes. Those assumptions don't necessarily hold.

The model is also making hidden assumptions about where high-level NPCs would choose to live. Again, those assumptions don't necessarily hold.

Suppose a medieval city-state has one city and 1000 small villages. According to your model, all the high level NPCs in the nation are to be found in the city and none in the villages. That's wrong. Powerful people don't choose to live in the stinking, disease-ridden city, they live on private estates that have small populations and themselves resemble villages.

Sorry, but it doesn't work.

 

[clearstream]

Why do you feel the need for a rule in the first place? Curious minds inquiring. Aren't the needs of the towns and cities dictated by your current story? About what feels right to your players' perceptions?

I feel your question gets at that most important consideration - as 5e players posting in a 5e forum we know we benefit from rules, but why do we need this rule? There are many reasons, but fundamental for me is Tolkien's principle that consistency is vital to a believable fantasy world. Rules help consistently resolve questions at the table, ideally with well considered and streamlined mechanics that resiliently debug issues that any given group may not have hit yet. Good rules also validate players at the table, through providing context and constraints. As a tier 1 PC I learn that I am one in one hundred. On gaining tier 2, one in a thousand! And then when creating challenges, it helps me to have a consistent guide to the size of the cast I am drawing from.

Philosophically, I value rules that take me in directions I may not have gone if I put the story on rails. Rules that breathe life into the world. If I know there are likely 2 tier 3 NPCs in this town, and the PCs have met one of them, it makes me wonder about the other one. Perhaps they decide they need to speak with a high level Monk. A dice roll takes my imagination in a new direction!

 

[clearstream]

The model is making hidden assumptions about the statistical distribution of settlement sizes. Those assumptions don't necessarily hold.

The model is also making hidden assumptions about where high-level NPCs would choose to live. Again, those assumptions don't necessarily hold.

Heh The model isn't "Fantasy-World-Sim v2.017". It's half-a-dozen sentences designed to be used on the fly by a busy DM! The assumptions aren't hidden! They're out in the open. We assume 1/1000 tier 2 character-class-equiv NPCs, for example. We don't know exactly who they are or where they live, but we suggest a DC for contacting one.

Suppose a medieval city-state has one city and 1000 small villages. According to your model, all the high level NPCs in the nation are to be found in the city and none in the villages. That's wrong. Powerful people don't choose to live in the stinking, disease-ridden city, they live on private estates that have small populations and themselves resemble villages.

I live in a small 9th century European town. Many of the grandest houses are owned by the powerful people of a nearby city. And it has been that way for centuries. That said, this isn't about locking our powerful NPCs into a final resting place. If we know that Waterdeep contains perhaps 2 epic tier characters, that gives us a good sense of the vacuum left by the death of the Blackstaff. Or we can get a sense of the magnitude of threat that could draw a handful of tier 4 characters together from the city to face it.

This isn't a trick, or a test. Or a plan to sneak unwanted rules into your game. It is a good faith offering of some streamlined rules that yield results consistent with the baseline D&D world.

 

[Jester David]

I'm not sure why this needs to be a hard rule.
I wouldn't want hard rules mandating how many people in a town were adventures.

(1 in 1000 is too high for my comfort level. 1 in 10,000 feels better. We don't need 30 people in a village of 67 able to cast spells.)