Monte-Carlo Measures of Monster Levels, Pt. 4

The devil is in the details. More discoveries on running OD&D monsters through a computer simulator a few million times each, here focused on some giant versions of real-world creepy-crawly animals:

Giant Ants: OD&D situates these creatures on the 3rd level table. This monster doesn't have any statistics specified in Vol-2, or even a suggestion for damage in Sup-I (like most giant animals do), so we necessarily turn to the Monster Manual. The basic type of giant ant is AC 3, HD 2, Atk 1 for the canonical 1d6 damage; the text indicates that this is a worker ant ("90% likely") -- and the simulator measures this simple creature at only EHD 1, which would suggest that we move it one table lower in OD&D. But the text also indicates another option (presumably 10% of ants): the warrior ant with HD 3 and a poison sting (save or die, of course) -- and this type the simulator assesses at EHD 5, which would put it one table higher than shown in OD&D. So here we have a dilemma: the worker ant is too weak, and the warrior ant too strong, for the given location in the OD&D random monster tables. I've left it as the warrior type in my charts, just because the poison sting makes it a little more interesting; perhaps that's a mistake thematically.

Giant Beetles: The type is shown on OD&D random table level 4. Sup-I (p. 18) suggests that Giant Beetles be given 3-30 (3d10) damage per bite; that seems highly excessive in our context of non-revised OD&D combat, because even Giants are originally given only 2 dice of damage (d6's). Looking at the Monster Manual with its half-dozen options for Giant Beetles, the one that seems the most appropriate is the giant Boring Beetle, with AC 3, HD 5, and Atk 1, now reduced on average to 5-20 points (5d4). If I lower this to simply 2d6 damage, to match it with Giants (and the only type on my list below Giants to get more than 1 die of damage), then the assessed EHD is 5, the same as its Hit Dice -- so no bonus to XP, but nicely situating it in the middle of the Level 4 table where OD&D says it belongs.

Giant Snakes: OD&D places these creatures on the Level 3 table; and there are so many issues to juggle with this one (again, we can only guess at it assumed Hit Dice, Attacks, etc.). Sup-I suggests that the Giant Snake should have both a poison bite and a constriction attack (if I read it correctly); a combination that doesn't actually occur on Earth for any type of snake. The Monster Manual thereafter takes a more naturalist stance, splitting up the types of snakes into either a giant Constrictor HD 6+1 or Poisonous HD 4+2 types (among others: Amphisbaena, Sea, and Spitting snakes, not considered here). So we have a number of different options to consider for our OD&D serpent.

Let's take a step back and consider the pulp literature for the type. Conan is known to deal with monstrous snakes in many of his stories (including famous cover artworks), so let's look there. Fortunately, I found a post compiling those giant-snake encounters on the Official Robert E. Howard Forum precisely one day before it's scheduled to be shut down (currently at www.conan.com; I'll be copying the content in comments below when I get a chance). Poster blanor notes that Conan fought giant snakes in 4 stories (Hour of the Dragon, Queen of the Black Coast, Beyond the Black River, and The Devil in Iron). As I look up the scenes in the various stories myself, I note that in each case they are described as a tremendous python, a constrictor type that tries to crush Conan or someone else in its coiling mass (the word "python" is directly used in all of the stories except for Devil in Iron; although tellingly the description of a "wedge-shaped head" is used uniformly in all of those stories). The serpents are each described as being variously 20 or 40 feet long (and The Scarlet Citadel has a whopping 80-foot snake that chases Conan for a while, but he never actually comes to blows with it). But the creature in Beyond the Black River is given an additional terrifying aspect:

That was the reptile that the ancients called Ghost Snake, the pale, abominable terror that of old glided into huts by night to devour whole families. Like the python it crushed its victim, but unlike other constrictors its fangs bore venom that carried madness and death. It too had long been considered extinct. But Valannus had spoken truly. No white man knew what shapes haunted the great forests beyond Black River.

Taking the Conan stories as a cue for the basic type, my list features the MM Giant Constrictor as the basic Giant Snake: AC 5, HD 6+1, can bite and constrict at the same time for 1d6 damage each (this requires an initial successful bite; thereafter it gets 1d6 constriction every round automatically, and can still bite normally as well; the victim can act normally meanwhile); this gets assessed as EHD 6, the same as its HD (so no XP bonus), but placing it one level higher than in the OD&D tables (and on the tail end of that table, in fact, almost into Level 5).

So perhaps we should consider some other options to rectify that. Take the MM Giant Poisonous type (HD 4+2). Unfortunately, the save-or-die poison makes this even more dangerous, at EHD 8 -- clearly into the Level 5 table, then. Or we could simulate the infamous "Ghost Snake" at HD 6 with both constriction and poison -- of course, that's even more deadly, at EHD 11 (pretty deep into the Level 5 monster table at this point). We could consider a mini-Ghost snake, 3 HD with both constrict & poison, as per Sup-I -- that's EHD 5, still one level too high.

If we decide to dial things down to a simple snake of 3 HD and constriction as its only ability, then in this case, we get EHD 3, properly placing it on the Level 3 table as OD&D is printed. (The constriction ability by itself always generates EHD = HD.) Of course, as DM you can create a snake of whatever hit dice and abilities your heart desires. For example, the Holmes Basic D&D Sample Dungeon has a 2 HD snake in room "S" (no special abilities noted; are we meant to assume this is a constrictor, poisonous, both, or neither?).


What do you use for baseline giant ants, beetles, and snakes in your OD&D game? Bigger, badder, and more fantastical stuff considered in the next post.

Devil's Advocate

Lest we forget our history, let's remember that there was a freer time for the publisher of D&D, when it was not yet taboo to probe possibly darker themes and subject-matter touching on real-world belief systems. The high-water mark was likely in August, 1979, in Dragon magazine #28, with Alexander von Thorn's article "The Politics of Hell". It's the featured article of that issue, running some 5 pages (or 20+ paragraphs). It opens with this unusual (and perhaps questionable) disclaimer by the author:

(Author’s note: The following article cannot be considered the official doctrine of either  Advanced Dungeons and Dragons  or the Roman Catholic Church. However, it is compatible with  AD&D,  and except for the parts about Asmodeus it is not in conflict with works on demonology as generally accepted by Catholic exorcists, thus enjoying tacit approval by the Church. However, this article does not have a nihil obstat; much of it is original, and it approaches the subject from a different angle than a religious tract would and should not be considered as such. The rise of Asmodeus is not documented in any major text on demonology, but very little original work on the subject has been done since the Middle Ages, so it is possible that the situation has changed. Perhaps Mr. Gygax has more accurate sources of information...)

The first half of the article is a mythology, to my eye a pastiche of Biblical and Dantean ideas, and twice referencing the Lesser Key of Solomon. This presents a historical tale explaining the overthrow of Satan by Beelzebub/Baalzebul, and then likewise by Asmodeus, in such a way as to explain why it is that latter figure who leads the Hells in official AD&D rules. It identifies the first coup with the real-world Renaissance period, and the second with the period of World War II. Von Thorn writes:

In fact, most people including the majority of the clergy, were not aware of the change in the leadership of Hell. To this day, when people think of “The Devil,” they think of Satan, and if the name of any devil is mentioned in a Catholic sacramental ritual, it is his (e.g. when the celebrant asks, “Do you reject Satan?,” etc.).

The latter half of the article presents information on three now-fugitive figures: Satan, Belial, and Astoroth (i.e., famous devils who had not previously appeared in works of AD&D). Here is the stat block and the first part of that ten-paragraph section:

A few details are given that would certainly be proscribed later on, such as: a suggestion that an actual paper contract between Satan and an interested PC be drawn up for clarity; special status for clerics of mainstream Abrahamic religions, etc.:

It is best to have the contract actually written out, with identical copies for the player character and the DM (which the player should study carefully before signing), because Satan is extremely literal, and he’ takes sadistic pleasure in twisting the intent of a contract by fulfilling its letter...

Naturally, a person cannot take any positive action to get out of a contract without first deciding to do so. Any Jewish, Christian or Muslim cleric of at least Patriarch level (such as a Cardinal, Primate, Metropolitan, Chief Rabbi, Ayatollah, Caliph or equivalent) can invoke the name of the Deity to save the person’s soul. However, they usually require some token of one’s devotion to the cause of good, such as the performance of some appropriate Quest, as the price of redemption...

It's likely that articles like this one by von Thorn -- including those by Ed Greenwood in Dragon #75, 76, and 91 -- touched a little bit too close to home in some circles, and were among the catalysts for the witch-hunts regarding D&D in the 1980's. You can see some of those cultural warriors of the period (notably Pat Robertson) still making the same warnings about D&D today. In order to survive as a business, TSR made references like the above completely prohibited from their publications, a taboo that survives to this day for owner of the official D&D license.

Armor of the Gods: Dots and Dashes

Quick observation regarding OD&D Sup-IV: Gods, Demi-Gods and Heroes (Kuntz & Ward, 1976): In some stat blocks the key "Armor Class" is followed by a colon, while in other places it is a long dash. This makes it very easy to mistakenly read many ACs as negative when they're really not. As one example, these Egyptian deities on p. 6 both have the same AC:

If you consistently misread the ACs followed by dashes, you'd have a lot of very weak creatures (like, otherwise playable low-level monsters) with ridiculously hard ACs: for example, in its first appearance in this work, the 6th-level Naga would be given AC −5, whereas in the later Monster Manual it more clearly appears with AC 5.

The majority of entities, even greater gods, tend have ACs capped at 2 (plate), the same as for monsters in the original rules. The only creatures I see listed in Sup-IV with truly negative ACs are: the Fenris Wolf (AC −2), the Midgard Serpent (body AC −4), and the Earth Queen (AC −3). For more of the rare monsters who have negative ACs in OD&D, see: Sup-I (elder dragons and will-o-wisps), and Sup-III (demons and ki-rin).

Monte-Carlo Measures of Monster Levels, Pt. 3

More observations and discoveries from coding and simulating the OD&D monster special abilities. See Part 1 for the table of Monte-Carlo measured monster levels (Equivalent Hit Dice, or EHD).

Undead and Energy Drain: One possible weakness of the simulated-combat model here is that it can't objectively weigh the value of long-term disabilities like energy drain, disease, and/or lycanthropy. In the scope of a single fight-to-the-death, these abilities make little difference. Of course, if a fighter of middle level can be assumed to have a magic weapon, then this cuts through all the undead defenses. So I was somewhat surprised to see wights measured at 1 EHD under their actual HD, and wraiths at just parity (arguing for no XP bonus, although higher types do start outstripping their base HD as a level of danger).

A few adjudications are necessary regarding OD&D energy drain, which might change your results: Does the target get a save? Does the drain reduce current hit points? To what XP level does the victim get reduced?

Personally, for some time I've been orbiting the zone of giving characters hit by undead a save to avoid the level-drain; however, the simulation here did not include that, and the EHD's for wights and wraiths still didn't evidence any boost for XP value. And yet I still like the texture of a saving throw; in the window where the player reaches for the die, rolls it, and watches for the result, it would seem like they get to "feel" the existential horror of the unknown in their gut, as opposed to the DM just announcing the loss as a done-deal-by-fiat. And it's consistent with giving a save for about every negative effect (like poison, paralysis, etc.) One remaining concern would be exactly what save to call for? I've been using the "Death" column (powers of undeath and all that), but it's the most generous save category, which feels a bit too soft, actually (almost 50% to save even at 1st level in the OD&D text).

Other decisions that seemed the most elegant while writing this in code: I had the energy-drain reduce maximum hit points, but not necessarily current hit points. Example: A 3rd-level fighter starts out at 15 hit points and gets hit by a wight; say the base 1d6 damage comes up "6", reducing current hit points to 9; and then the energy-drain kicks in, reducing level to 2, and maximum hit points proportionally to 10. So in many cases like this, the energy-drain may have no practical effect on current hit points or increased risk of actual death. This would be very different, and more dangerous, if the mechanic was to actually keep a record of damage taken and dynamically compute current hit points as maximum - damage when checked (but that doesn't resemble what I see most players doing at the table, so I didn't implement it that way).

Also, it seemed most elegant to just drop XP to 1 under the current level -- that is, the same mechanic used in the limit on gaining more than one level at once. That constitutes maximum generosity to the PC in question, and a single level loss is sure to be regained at the end of the given adventure when new XP is awarded (although still might be a lot of XP over the bridge, or multiple level losses a more lasting penalty). In the past I've used proportionally-rated XP drops (same relative location in XP as in the starting level), but I kind of like not having to pull out a calculator for that anymore. Alternatively, I think some rulesets specify dropping to the start of the prior level; the most punishing interpretation you could make.

Giant Hogs: Giant hogs are listed on the 3rd-level table for OD&D random monsters, and apparently in Gygax's Castle Greyhawk, the 6th level was nothing but a maze with "dozens" of giant hogs and lycanthropic leaders (link; and see below). Now, even the Monster Manual doesn't have an entry for "giant hog", but it does have "boar, wild", at 3+3 Hit Dice (same as the "3 dice" mentioned by Gygax regarding the Greyhawk level). This is a fairly weak opponent, only assessed at EHD 2 in the simulator (but at least it marginally belongs in the indicated table); note that the MM ability of fighting for a few rounds while in negative hit points is not something I could implement easily in the Arena code (in breaks the standard mechanic for hit points, and also breaks the Arena expectation that every fighter has an identifiable survivor/winner). On the other hand, if we were to use the 7 HD "giant boar" from the MM, this type would be much stronger, assessed at EHD 6, and so would belong at the upper end of the next table higher. So of the two, the Monster Manual's "boar, wild" has more evidence of being the better fit.

Lycanthropes: I only implemented the base type of lycanthrope, the Werewolf (you'll see that the same thing happened for Giants and Dragons, say). I was kind of surprised to see how underwhelming it is in practice. It's the only monster in the system assessed at two pips lower in EHD than its actual HD (i.e., EHD is only half HD). Assuming a fighter with a magic sword by this level, its defense is not relevant, and neither is the lycanthropy effect an increased risk to lose a given fight. If we assume no magic weapon for our fighters, then the EHD jumps from 2 to 4, the same as its HD (the Arena simulator does assume that fighters have a silver dagger to draw out in any case, but in that case their damage is halved from d8 to d4). Perhaps if we randomized from among the 4 types of lycanthropes in the book, this overall result would be a bit different (although even then HD are in a narrow range from 4 to 6, so likely not a huge difference).

Gargoyles: Similar to lycanthropes, and more critically, their main special ability is their defense in not being hit by normal weapons; and therefore the key to their measurement is at what level do we assume fighters will usually have a magic weapon? In my model that all fighters in the arena have the +1 sword, you see that the EHD turns up at 4, the same as its actual HD (and so: argues for no XP bonus). Of course, if your model/assumption is that fighters only get magic at some higher level, then the Gargoyle EHD will follow suit (at exactly the same number; the simple proof is left to the reader).


That's it for this week. Open questions: At what level would you assume that a fighter has a magic weapon (and so gets to hit high-level Undead, Lycanthropes, Gargoyles, etc.)? And how do you adjudicate the details of  Energy drain -- Saving throw? Hit points effect in combat? XP reduced to what level?

Link: OD&D Print Comparisons Video

More great stuff from Jon Peterson of Playing at the World:

Monte-Carlo Measures of Monster Levels, Pt. 2

See last week's post of the output of the Arena monster-measuring program (link). Some more observations and discoveries as I thought through implementing all the monster special abilities in code:


Position in Monster Tables: In OD&D the random monster tables were organized in (of course) six different "monster levels". In the table in the prior post, I've shaded in six alternating groupings that follow those six levels as closely as I could tell. Generally speaking, the relative rankings are about the same; the monsters the gained or lost their position on a particular table are noted in the TC column, with a "<" or ">" as appropriate. There are 4 that want to go up a level, and 6 that suggest going down, in this analysis.

You can see in this model that Monster Table 1 would be composed of all EHD 0 monsters; Table 2 would be about EHD 1-2; Table 3 approximately EHD 2-3; Table 4 EHD 4-6; Table 5 EHD 8-12; and Table 6 EHD 13 and up, roughly speaking.

On Points for Special Abilities: At the end of the day, the main theme of this blog might be: "Creating new elements for a game is easy, but evaluating those elements is very hard; and a table of summed points is almost surely broken." Speaking of XP, pretty much every edition assumes that a special ability of a certain type will be worth the same relative boost for any monster that possesses it. But consider a monster who, say, has poison, paralysis, and petrification attacks, but can only use one at a given time; then the effect is about the same as having only one of them (there is a marginal added value for having the different options, but the value will be pretty small). Or, as we will see: save-or-die hits might be more useful against a high-level PC with many hit points, but negligible against a low-level PC who would die from the one hit anyway (and hence: more valuable for high-HD monsters, and less valuable for low-HD monsters). Actual examples include the Gold Dragon with its two different options for breath attacks, or the Demons of Sup-III with their multitudinous spell lists.

Missing Monsters: Almost all the monsters in the OD&D random dungeon monster lists were included in this analysis. But: no NPC spell-casters were included (magic-users or clerics), because implementing the entire D&D spell list, and AI to choose from the different options, was outside the scope of this project (and secondarily, it also seemed a bit outside the theme of a gladiatorial arena). Also: the Ochre Jelly could not be included, because it's entirely unkillable by weapon blows (and so invulnerable to the attacks of our comparative fighters).

Zero-Level Monsters: All of the monsters on the OD&D "Level 1" table (Kobolds through Spiders) were evaluated as Equivalent Hit Dice zero (EHD 0). This is something of an artifact that the Arena best-level process can't output fractional values; after all, it only has integer-valued levels of fighters to choose from as opponents. In other words, these monsters are a fair fight, or less, for a single 0-level man with 1d6 hit points bearing chain, shield, and a sword. I wouldn't plan on reducing any XP awards from the base Hit Dice; I would still award a full 1 HD or appropriate fraction based on actual HD. So I blanked out the "Diff" and "Mult" columns here to avoid suggesting the reduction in XP in this range.

Centipedes and Spiders are basically as seen in the Monster Manual. (Centipedes get 1-2 hp [1/3 HD here], no damage, but poison at a +4 save bonus; Spiders are of the "large" variety, HD 1+1, 1 damage, and poison at +2 save.) Related to the point on special abilities above, it's interesting that even this save-or-die poison doesn't actually boost their threat level past level 0 in this analysis. We might observe that for a fighter with a single hit die, whether you're hit for 1d6 damage or poison, the effect is indistinguishable; you're probably dead. However: this value may be different if you team a lot of the monster type against a higher-level fighter (like say: consider 10 goblins vs. a Lord, against 10 spiders vs. a Lord; then one hit in the latter case is more worrisome), but this is not visible in the current model. In the past I considered doubling the save bonus indicated for centipedes and spiders; now I'm pretty convinced that they're reasonable as written, and may not even be worth any XP adjustment at all.

As an aside, if we take out the +1 sword given to our nominal fighter opponents, then it makes no difference in the assessed EHD level for these 0-level monsters. Among higher-level monsters, the trend would be to adjust +1 or +2 EHD higher, although the magic-to-hit monsters would of course turn unbeatable (immeasurable) in this case.

Toads, not Thouls: Many of us know that "Thouls" were listed in OD&D monster Table 2, without any statistics or description given for them in those rules. Tom Moldvay's later Basic D&D detailed a Thoul with 3 HD, two attacks, paralysis like a ghoul, and regeneration of 1 hp/round. Gygax separately communicated his take on the Thoul as 4+2 HD with the same abilities.

What was news to me recently is that the entry for Thouls did not appear in the 1st printing of OD&D; what appeared originally in that slot were "Toads". Now, this makes a lot more sense to me. First, giant frogs and toads seem like an intrinsic theme of early D&D, and with all the other giant-animal types, it seems weird for these amphibians to be entirely missing. Second, evaluating the Gygaxian Thoul would put them at either EHD 8 or 12 depending on the attacks permitted, and so would be misplaced on the random tables by fully 3 levels (out of the 6 total). Instead, by returning the Giant Toad to its rightful place (using MM stats), their power level fits right into Table 2 where they originally squatted.

Why were Giant Toads taken out of the later printings? Partly this has the smell of erasing the thumbprints of Dave Arneson, who is perhaps chiefly remembered in official D&D publishing for his "Temple of the Frog" complex in OD&D Sup-II. (Link to discussion of toads and thouls at Dragonsfoot.)

NPC Fighters: NPC fighters, as they are shown in the table, conveniently get assessed at an EHD equal to their actual level (i.e., true HD) in each case. Like the protagonist fighter, they get abilities of 3d6-in-order, and normally-rolled hit points. But they also get plate mail and a 5% chance/level for a boost in magic to armor, shield, and weapon. This is partly offset by the guaranteed +1 sword for the baseline fighter, so on average the difference is only 1 pip to hit (at least until we get into very high levels, in theory).

As an aside, here's how the simulator generates magic arms: for each NPC fighter level, we make a separate 5% roll to see if that fighter's armor, shield, and/or weapon should be boosted by a +1 magic bonus. Then we roll again at the next level, and so forth. This may produce up to a +5 magic bonus if several rolls succeed. Note that this is a hairs-breadth difference in probability from the straight 5%/level indicated in Vol-2, but it smoothly generates magic items of higher values, so it's very close and I actually like the elegance of this method a lot better.

In fact, I like this so much I may start doing it when I manually create NPC fighters. Say: Take 3 d20's of different colors. Roll this group once for each level of the NPC. Each time a "20" shows up, tally another magic pip on the associated armor, shield, or weapon. This might take a minute longer than just a single percentage roll, but the results are a smoother distribution. It doesn't directly generate any of the exotic weapon types (flaming, +3 vs. trolls, etc.), but even that I kind of prefer; normal NPCs won't have them, and only adventuring the underworld can dig up those special types. Personally I'm always aggravated when some 4th-level sergeant winds up with a sword of wishes and I have to spend time thinking about how to adjudicate that.

That's it for this week; more next time.

Link: Precursor to Chainmail Fantasy

Jon Peterson of Playing at the World has another ground-breaking, possibly bombshell piece of research that he's dug up about the origins of D&D. Namely: a set of fantasy miniature rules for Tolkien's orcs, wizards, dragons, etc., written by one Leonard Patt, and published by the New England Wargamers Association in 1970 (and recipient of "Best of Show" award at the Miniature Figure Collectors of America convention that year).

Notably, much of the rules and rules language is shared by the later Chainmail Fantasy supplement by Gygax and Perren (and hence incorporated into D&D after that). I find these observations by Peterson to be fascinating and compelling. I, for one, am very happy to have a better understanding of the origins of the game from this work. Thanks once again to Mr. Peterson for bringing this to light, and also to Mr. Patt for his initial ideas!

Playing at the World:
A Precursor to the Chainmail Fantasy Supplement