Friday, November 27, 2009

Love in the time of clerics

The possibility of death by disease was very real in history. I've often wondered how the presence of D&D-type healing magic might impact the course of an outbreak of some plague or other. Having a little bit of time on my hands, I decided to crunch a few numbers. It's a very basic analysis, omitting a lot of ancillary factors, but I think it's instructive.

Let's crunch some numbers.

Just to take something as a baseline, the Black Death of Europe (1348-1350) killed about 33% of the population of Europe. That's approximately 1.1% of the population per month. Now, I know that's an imperfect figure, because it doesn't take into account births, or other causes of death, but given my reading on the subject, it's actually not too far off, when brains mightier than mine apply themselves to the death-rate problem during the Black Death.

My question would be, how many clerics would it take to stem the tide of such a virulent disease? Would a Black Death be possible in a D&D world, or would the grace of the Gods be enough to stem the tide of infection?

Consider this: the clerical spell Cure Disease is a third level spell. That means only a fifth-level cleric can cast it, and it requires a 9 hour rest time (minimum) to recover (plus 10 minutes to actually cast the spell). Assuming those fifth-level clerics are casting their spells at the maximum rate, that gives:

720 hours per month ÷ 9 hours per spell = 80 spells per month

Wow; now that I actually work it out, that's pretty measly, and that's working full-out, with nothing else going on. And that's only counting fifth-level clerics!

But paladins have the power to cure disease as well; once per week at fifth level. So count paladins as 1/7th of a cleric. Fifth level cleric, that is.

To stem the tide of the Black Death, you'd need 138 fifth-level clerics (or their equivalent in paladins, at the going rate of 7 paladins per cleric) to cure the new cases of disease, per one million people:

1,000,000 people x 1.1% = 11,000 dead per month

11,000 ÷ 80 = 138

The question becomes, how many clerics are there in the setting? If you've got 138 5th-level clerics per million people, you can hold off an epidemic as virulent as bubonic plague. Anything short of that, and you've got a problem. The extent of the problem is directly proportional to how far short of 138 5th-level clerics are available, per million people.

In a city the size of Rauxes (pop. 41,000) or Greyhawk (pop. 58,000) that translates to 7 or 8 fifth-level clerics, respectively. I think that is entirely reasonable. In a more rural setting, where higher-level clerics are more scarce, the story might be different. Hommlet, for example, could be served by Terjon and Jaroo (twice as much as the small village needs) and come out unscathed.

Ultimately, unless the DM invents some sort of magic-resistant or extremely virulent (beyond the bounds of the black Plague of Europe) plague, clerics of a typical campaign setting should be able to handle the problem. Of course, it wouldn't leave them any time to do anything else, which might be an opening for some enterprising Arch-Daemon to wreak havoc...


Jerry said...

Not really D&D, but there's a great scene in Charles Sailor's "The Second Son" in which Joe the Construction Worker/Son of God, after some catastrophe or epidemic (it's been decades since I read the book, I wish I still had it) starts treating his ability to heal the sick as an assembly-line ability.

As soon as he stops treating them as miracles, the miracles stop coming.

satyre said...

The figures also assume that every cleric will be healing - which is not the case among some evil clerics, particularly Nerull and Incabulos.

I imagine them locking down the temple or encouraging situations like the Decameron or Poe's Masque of the Red Death where the faithful/wealthy hide while death stalks the streets.

Now you've given me an idea about an Incabulos temple and wererats working together... :)

sacha3791 said...

Historical nitpicking alert! I think you may need to revisit your figures if you want to employ The Black Death as your example disease. This plague wiped out almost 50% of Europe during the fourteenth century. London alone suffered an appalling 40% loss of its population at the time. I realise that you have used 33% as an approximation, I just think that it's a little on the low side.

Joseph said...

Sacha: I was going with a 33% death rate, based on many different sources. The figures I've found range from 25% to 50% as the upper margin.

Just to take London as an example, in 1348 the city had a population of approximately 70,000. Within three years, 20,000 people had died. That works out to a 28.5% mortality rate over 36 months (making my 33% assumption a little high).

I got that particular figure from, but it's not out of line with other figures from many different sources. I'm not saying no one uses your 50% mortality rate figure, just that it's not the only one out there, and it's the high end of the curve.

Plus, don't forget that the overall European death rate is over a longer period of time than the mere 3 years that the Plague ravaged England. So when you're figuring a monthly mortality rate, that needs to be taken into account as well.

Eric Haas said...

The death rate would have varied from place to place, as well. It likely would have been higher in overcrowded cities, and lower in rural areas.

To really know if D&D clerics could handle a plague, I think you need to take account of a few more details.

How long after someone is infected does he become infectious himself?

How long is it before symptoms begin to show?

Once symptoms begin to show, how long does the person have to live?

How long does it take a symptomatic person to get access to a cleric?

A disease with a long latency that killed rapidly once symptoms appeared could still overwhelm the clerics.

sacha3791 said...

Joseph: The joys of historical study, eh? In which sources do we invest our trust? I've read sources that postulate a loss of 50,000 people in London, during 1348 alone. Of course, we could always get into a semantic back-and-forth discussion about how one precisely defines 'London' during this time. ;o)
Of course, none of this is particularly important and I was fascinated by your thoughts on this subject. I'm an ardent reader of your blog and have no interest in getting on your nerves with scholarly pedantry arising from the Black Death, so I'll shut-up now.

seaofstarsrpg said...

It also depend on if the sickness come in nicely measured doses or in massive waves. If it strikes in waves, even a good number of clerics might have trouble containing it, especially if they had to use some of their resources keeping themselves from dying of the plague.

John Adams said...

Wow! The kind of fantasy rpg I really like! This pastor only had one math class in college, so I'm not good with numbers.

I will say that many good faiths will also have some scrolls of cure disease as well as maybe a minor artifact with healing properties.

E.G.Palmer said...

I don't see anything wrong with your numbers, Joe. The thing that comes to mind is the question of whether or not the Gods would choose to grant their divine magic in such a way.
They don't have to grant a cleric a spell if they don't want to, and it could be that they don't want the plague stopped. They may have sent it.
In this situation, I just treat clerics and paladins like firemen fighting a forest fire. Maybe they can slow it down, or save some areas, but they're probably just going to have to let it burn itself out.

rainswept said...

I'm going to agree with E.G.Palmer - a 'disease' that is poised to wipe out 1/3rd of the population of your typical D&D campaign setting would almost have to have, if not a divine origin, then divine sanction.

Otherwise you'd assume that the gods would intervene in a somewhat more efficient way, no? Like with some crazy disease-busting artefact that was "always buried beneath the Mad Caverns" nudge-nudge-wink-wink; just waiting for Captain Trips to come along and motivate the PCs into digging it up.

neofish said...

I think I'd definitely have to go with the folks that postulate divine intervention. In a setting where gods are real, then this level of catastrophe couldn't happen without their involvement. It would have massive repercussions on their churches and cults. A god of disease would almost certainly be promoting it, and likely be opposed by 'good' gods. That being the case, how about a number of evil clerics actually going around and casting 'cause disease' to help spread infection or counter the good clerics activities. Or a targeting of cleric / paladins to stop them carrying out their work. Where does the god of death stand on all these people being snatched from his / her grasp by interfering priests? I think there are too many variables to accurately postulate whether a Black Death like plague could be stemmed somewhere like Oerth. In a magic rich environment, there would be many impactors on its spread.

Welleran said...

Interesting post. One thing your math does not account for is the mechanism and rate of re-infection of those previously cured. Does a Cure Disease spell leave one with the immunity that you would have otherwise got after a full round of the flu or some other disease?

So many imponderables!

UWS guy said...

it only takes 4 hours of rest to regain 1-3rd level spells per 1e rules.

Wonderful idea for a post though.

UWS guy said...

I don't know how divine intervention would work. Assuming there are as many evil gods as there are good (plus demons and devils). Any intervention by forces of light would be countered by darkness.

Which is why gods let heroes do the dirty work. Think of proxy wars between the soviet union and USA.

Nagora said...

As far as I can see, it takes almost 7hrs to recover a Cure Disease: 10minutes to cast it, 6hrs rest, and then 45min of prayer. Total 6hrs 55min.

Of course, a 6th level cleric gets 2 back for only 45min more.

The speed of detection does seem an important point - can you cure a person before they spread the disease and can a person get help in time once they know they have it?

Justin Alexander said...

A few thoughts:

(1) You're assuming that the Black Death has a 100% fatality rate. I don't think that's actually true. (IOW, there may have been far more than 33% of the population infected with the disease during those years.)

(2) OTOH, it's unlikely that 33% of the population would contract it if you had the ability of modern medicine to quickly detect the disease and intercede before the infection spreads.

Which is what D&D-style magic gives you.

So out of those 1,000,000 people, 11,000 people aren't going to get sick because the clerics of the local church detected it early and shut the disease down before it could reach plague proportions.

(3) I also think it likely that most centers of civilization would probably prepare scrolls or other stockpiles of magical resources so that they wouldn't be entirely dependent on the clerics' daily spellcasting limits when a plague hit.

Assuming you aren't in a constant state of plague, you can prepare for a rainy day with far fewer clerics.

(4) OTOH, you've got gods of pestilence; evil clerics; and magical diseases of all sorts. (I use the latter method to unleash a vicious plague in The Black Mist.