D&D’s most original addition to fantasy is the dungeon: an underground nightmare maze, a place with alien rules that must be mastered if you are to survive, a place that has no good reason for existing, a place that you explore for its own sake.

In its 45 years, D&D has spawned a video game industry that’s worth more than either the movie or the book industry. Dungeons, dragons, leveling, character classes, and loot drops define video game design space. But books, movies, and TV shows haven’t absorbed much from D&D that wasn’t in Tolkien.

In medieval and modern fantasy literature, you’ll frequently find magic swords, but no magic armor; wizards, but no clerics; and dragons, but no dungeons.

It’s the dungeons I miss.

I’d watch a TV show or read a modern book about people exploring a torchlit, hostile megadungeon: solving puzzles, bashing down doors, fighting strange and terrifying monsters. I’m not talking about a show with a set-piece in a tomb or sewer: there are plenty of those. I’m talking about the dungeon as a main character.

There’s just not that much content like that. Even most of the D&D novels I’ve read are more likely to spend more time on Tolkienesque wilderness quests than on dungeoneering, with maybe a few set pieces in a tomb.

So here’s where I need your help. I just had knee surgery and I’m stuck in bed. I’m looking for book, TV, and movie recommendations featuring dungeons.

Here’s the well-known, post-D&D fiction that I can think of with dungeon-crawl settings. Let me know what I missed.

Labyrinth: This is a pretty pure example of the breed. It takes place almost entirely in a dungeon. There are puzzles and weird monsters. The rules of the labyrinth are consistent but weird.

Indiana Jones and the Temple of Doom: The series as a whole is a travelogue, although the dungeon sequences are so good that they transcend set piece. Still, Temple of Doom is the only installment which really can be described as a dungeon crawl.

Cube: Cube is set entirely in a classic death trap dungeon. It’s got the puzzle solving, the location as the main adversary, and the claustrophobic dread that comes from knowing you’re a first level character in a module for levels 8-12.

Stranger Things: (mild spoilers ahead) Stranger Things is explicitly about D&D, and in season 2 they do dungeons pretty well. The tunnels of the Upside Down teach you to keep an eye on the ceiling; to use a map instead of a trail of crumbs; and to bring lots of flaming oil. That’s pretty D&D. Still, the dungeoneering-per-minute ratio is low.

Dungeon series: During my D&D-obsessed youth, I started reading the Dungeon series, edited by Philip Jose Farmer. I couldn’t get into it. It’s called the Dungeon series, though, so I suppose it’s probably got dungeons in it?

Maze Runner: A young adult book where teens have to learn to navigate a dungeon. Fits the bill even though the protagonists spend a lot of time in the safe central camp, having teen feelings, and not out there runnin’ the maze like I want them to.

I have no clue about anime. I suppose there must be some show which is exactly what I’m looking for, right?

OK guys, what have I missed? What are the great examples of dungeoncrawl literature of the past 50 years? Again, I’m looking for something where the characters’ primary activity is exploring a series of dangerous interior spaces. Does literature like this exist?

I have to take a break from D&D content today to talk about what’s on all our minds in these dark times: Game of Thrones Season 8 Episode 3. That’s the one with the battle of Winterfell. You know, the episode that looks like they forgot to take the lens cap off. Lots of spoilers ahead.

This episode was reasonably well-shot (despite being dark) and expensive-looking; it also had a number of good set pieces. Its only problem was that not a single DAMN thing made any DAMN sense.

That may sound like hyperbole. But if you are to understand me at all, you must know that I abhor hyperbole above all things. Please imagine me making earnest yet steely eye contact with you as I tell you, my voice quavering with sincerity, that I could spend a full and rewarding lifetime unpacking the preposterous things in GOTS03E08, and when I laid down my burden at the age of 95, I could still say, “There was so much more to do. If only I had more time…”

I never knew it before, but I’ve been training my whole life to be a S03E08 mocker, and I will give it my all. But the sheer weight of absurdity is too much for a single mortal to lift. That’s why I’m pulling in reinforcements. Like an army of implacable and unstoppable Dothraki warriors, Rory comes thundering to my rescue. Between the two of us, perhaps we can get through a recap of this episode.

Before we start: Some may object that the points we’ll make in this article are nitpicks. For the most part, I don’t think they are. I think that, from the point of view of in-world logic, the episode was incoherent. It only made sense as spectacle. Therefore, it was bad fantasy.

I believe that one of the attractions of good fantasy is that it rewards examination. A good fantasy text has a world of detail beneath the surface: fans can get lost in those details, inhabiting the world along with the author. You can have the highest budget, the best actors, the finest CGI, and the slickest production in the land, but a lack of reverence for the plausibility of your world is as intrusive as a boom mic in the shot.

Some may say, “Game of Thrones is popcorn fantasy, don’t sweat the small stuff!” But if you didn’t like excessive analysis, you probably wouldn’t be on this blog, right?

Let’s recap this episode, shall we, Rory?

0:00: The beginning of the episode is effective, tense, and absurdity-free. Nervous warriors await the coming of the undead army. Everyone heads to their posts: Bran to the godswood*, the army to the field*, the noncombatants to the crypt*, and Jon and Dany to a hill nearby*. We also get one shot of Jon’s wolf, Ghost. Cool, we haven’t seen Ghost in a while! Can’t wait to see him finally tear some undead dudes up!**

*Note: I said this part of the episode was absurdity-free, but technically, everything asterisked is pretty absurd. Which turns out to be be almost everything, actually. We’ll get into it later.

**Note 2: Ghost never does anything at all in this episode.

0:09 Oh, cool, Melisandre the Red Woman arrives! Everyone looks surprised. She uses a magic spell! She sets the swords of all the Dothraki on fire! It’s really cool looking and still not absurd. Then she remarks to Davos, offhand, that she’ll be dead before the dawn. I guess she can see the future! And the future is grim!

0:14: The Dothraki, swords ablaze, ride off into the darkness, presumably to fight some wights they saw? Ser Jorah and Ghost go with them.

0:14:30: The distant fire-swords wink out one by one. The Dothraki are all dead. We get horrified reaction shots from everyone. No one, like, lifts a finger to help, though.

0:15: About 5 Dothraki run back on foot, along with Ser Jorah.

OK, let’s take a break and TALK ABOUT THE DOTHRAKI.

Paul: First let’s stop and go over what THE CHARACTERS know about the undead.

1. The wights (low-level zombies) and white walkers (high-level zombies) can’t be effectively fought with regular weapons.
2. They are only vulnerable to fire, dragonglass, and Valyrian steel.
3. The Winter King can raise dead people as wights. So if you lose a battle with wights, your numbers decrease and their numbers increase. That’s one of the horrors of fighting the implacable dead.

Again, the characters on the show all know this. Jon, Samwell, and Tyrion have discussed it ad nauseam. So what was their plan with the Dothraki charge? “LET’S SEND THE DOTHRAKI OUT WITHOUT FIRE, DRAGONGLASS, OR VALYRIAN STEEL.” We, the audience, can clearly see that the dothraki are using their traditional curved swords, no dragonglass in sight. And that Melisandre fire spell was a happy surprise! That was not part of the plan! So apparently the plan was to send them out, effectively unarmed, to be slaughtered, for what – so they could be raised to bolster the undead army? Who signed off on this plan? The Night King?

Rory: Also, and this is a common criticism at this point, but the Dothraki are basically light cavalry, and NO ONE uses light cavalry this way. Light cavalry typically use their mobility to flank enemies after infantry have already engaged, to charge or run down ranks that have already been broken or retreating, and to attack vulnerable and exposed forces, such as archers. Attacking a nebulous mass of undead at the start of a battle is probably the stupidest use for light cavalry one can imagine. If they had been a typical force of mortal spearmen, we could expect a similar result. Anyone who has played Shogun Total War or any of its sequels knows this, and the fact that it’s such a common criticism should be a sign that this isn’t exactly advanced military tactics. It’s really insulting to the audience.

Paul: By the way, what was the point of Melisandre lighting the Dothraki swords on fire? It DIDN’T DO ANYTHING. Melisandre sees the future! Granted, all the action happened offscreen and in the dark: I can barely tell what’s happening in this battle in the present. So maybe her future-reception was a little unclear. But still: why did she even bother to burn what had to be a level 7 or so spell? I guess the Lord of Light was like, “This seems like a good use of my power. I know it won’t do anything. But it will look cinematic at least.”

And that’s really why this whole scene happened. It was glitz at the expense of logic. We’re expected to forget the rules of the show, and to accept the characters forgetting the rules of their own world, in exchange for a cool one-minute-long set piece. Fantasy storytelling at its best!

Here are three ways the show runners could have improved this scene 1000%.

1. Show the Dothraki with dragonglass weapons.
2. While the Dothraki charge, have one of them yell “LEEROY JENKINS!” Then Sansa yells, “Oh no, those undisciplined Dothraki deviated from our plan! Hold your ground, everybody!”
3. Have Melisandre’s spell be part of the plan from the beginning.

Really, though, why were the Dothraki sent to the slaughter? Not for any really good in-world tactical reason. They were sacrificed for a dramatic reason: to demonstrate how scary the wights are. The triumph of dramatic logic over world logic is a theme in this episode that will return again and again and again and again. In fact, it may be the besetting sin of post-GRRM Game of Thrones.

Rory: I mean, the stated goal for all of this is not to win specifically, but to goad the Night King out of hiding. But you know what might actually do that? How about a force of highly mobile horse archers armed with Dragonglass arrows that could harry an army of undead who, for the most part, seem totally unequipped to deal with an enemy at range? That actually seems like the kind of thing that might annoy a white walker who is riding, literally, their only effective answer to a mobile force attacking at range. Like sure, the smart move is probably just to ignore the Dothraki anyway until they literally run out of ammo, but it does take a pretty disciplined commander to watch their forces torn apart with no repercussions and not wonder if there’s SOMETHING he could do. And you know what, if he has an answer I haven’t thought of or some hidden trick, that might actually be pretty satisfying.

Paul: So that’s why the Dothraki have to die. But why do the DOTHRAKI have to die? Well, here’s one ugly possibility. It’s a horror movie cliche to have the monster kill the people of color first. Usually it’s one or two individuals. But what about killing several THOUSAND people of color first? That’s not a cliche, right, and not weird at all? (by the way Ser Jorah and the albino wolf survive the charge). (Also these show runners wanted to make a show about what if the confederates had won)

Rory: Beyond the more generalized racism, I’m just pissed we’re seeing:

• The destruction of more or less an entire culture here. Jesus Christ. Way to not give that the weight it deserves, guys.
• Dropping the ball on literally years of build up for an INCREDIBLY throw away scene. When we first heard about the Dothraki in season 1, they’re painted as this unstoppable horde with only a narrow strip of sea between them and the domination of Westeros. King Robert literally said that if the Dothraki arrived in Westeros, all the nobility would wisely hide up in their castles since no one could face them in open battle while they ravaged the countryside and the people realized their leaders had forsaken them. Guess all that was just a set up for a scene where they fruitlessly charge some undead to set the stakes for the battle. Game of Thrones often plays with expectations, don’t get me wrong, but this wasn’t given the weight it deserve. It felt incredibly callous.

Paul: I agree, it feels callous. That seems like a weird word to use in the context of Ned Stark and the Red Wedding. I think the difference is that, in early Game of Thrones, you had the sense that anyone could die because that’s just how the world is, man. In late Game of Thrones, you get the sense that certain characters have plot immunity until the show has given them the sendoff due to their station. In fact, the show runners mention that in their commentary on this episode. When (spoilers ahead) some characters die later in this episode, the show runners describe how each is given a special moment. Therefore, the grandeur of your death is a direct indication of how much the show runners value you.

Rory: Also, the Red Wedding had a certain “you reap what you sow” feel to it. Robb Stark selfishly marries for love and suffers the consequences. Catelyn thinks she can depend on ancient tradition to protect them only to realize the Freys care more about a slight than they do about their own honor. There was build up to that moment. Not so with the fruitless Dothraki charge.

OK, that has to be enough about the Dothraki charge. Let’s move on to other things. After all, we’re only on minute 16 here.

Paul: Hold on. That’s another thing. The engagement between thousands of Dothraki and unknown numbers of wights seems to have taken about 30 seconds – a handful of D&D combat rounds. GIT ‘ER DONE, right?

You may argue: maybe time was compressed for the sake of the show. Maybe we are skipping over 10 minutes or so of horrified reaction shots as the rest of the army continues to not lift a finger to help.

OK, now let’s move on here, for serious.

Read the rest of this entry »

Last month I wrote up 20 festivals suitable for dazzling your characters on their visit to the big city. Of course, city folk and country folk celebrate very differently, so I’ve also written up 12 country fairs, some of which are stranger and more dangerous than their urban counterparts.

Country Fairs (roll d12):

1. Pumpkin festival: This pastoral fair features pumpkin-eating, -tossing, and -growing contests, as well as prizes for the best pumpkin-related songs or plays. At dusk, everyone locks themselves inside their houses. This festival is also celebrated by goblins, who put pumpkins on their heads and invade human villages after dark, committing vandalism and mischief and trying to lure people out of their homes and carry them away. Possible encounters with entertainers, halfling scouts, pumpkin-tossing champions, and goblins with pumpkins on their heads.
2. Flower fair: a less watered-down version of the city Flower Festival: it’s usually, but not always, held in the spring. It features dancing, feasting, ancient traditions and songs that no one understands anymore. Bizarre, ancient activities include “Tie a Pig to a Goose” and “Wear as Many Lit Candles as Possible”. Druids choose two monarchs of beauty, who perform a secret rite to renew the seasons. Possible encounters with druids, green knights, village leader cult fanatics, and entertainers.
3. Bridal festival: It’s considered lucky to get married on this day: there are usually more prospective brides and grooms than officiants to perform the weddings. Any visiting cleric, druid, or paladin will be begged to perform at least one wedding. Other visitors may be proposed to.
4. Monster night festival: Soft city folk celebrate a jolly and toothless version of this festival, but in the countryside it’s the real deal. It’s taboo to hurt a monster on this day. Instead, villagers ritually praise monsters and leave sacrifices of food and coins near known lairs. In particularly bad years, a youth or two may be left for the monsters as well. Possible encounters: minstrel entertainers, priests, cult fanatics, and monsters of all types: particularly common are ogres, perytons, and hags.
5. Pie fair: Prizes for pie eating, throwing, and baking. People will do anything to get their hands on each others’ closely guarded baking secrets. Possible encounters: halflings, champion pie throwers, hags with a sweet tooth.
6. Mistletoe festival. Worshipers partake in druidic rituals, dances, and hunts, and, in secret, older and darker rites. Possible encounters: elves, druids, scouts, cultists.
7. Goblin market: a traveling fair run by elf and fairy folk of dubious morality. For sale are beautiful but inexpensive things and minor magic items. Items can be bought for gold or favors. Attracts elves, pixies, entertainers, alchemists, merchants, goblins, green hags in disguise, and wicked fairies.
8. The bastards’ fair: Uninvited and unannounced thugs, thieves, assassins, and other rogues descend on a community for a few days, expecting to be fed. Criminals use the fair to make underworld contacts, fence goods, and hire assassins.
9. The village games: Village champions are crowned in wrestling, racing, dagger throwing, wild horse riding, poetry, singing, and other contests. Usually features rivalries between local champions and itinerant adventurers.
10. Devil’s dance: People dress like devils and commit innocent mischief, acting rude and committing minor pranks. At dusk there is a country dance. In troubled villages which harbor actual cultists, green hags or evil warlocks, mischief can be anything but innocent and may claim lives.
11. Picklefest: Who can make or eat the sourest pickle? Who can best extol the virtues of the pickle in story and song? Pickles are hung from trees, given as gifts, and gathered in straw baskets by children. Possible encounters: hungry halflings, dwarves, and local champions with cast-iron stomachs, all eager to test their mettle in the pickle-eating championships; gamblers filling out their brackets.
12. The great hunt: On this day, sacred to a nature god, foresters hunt game such as deer, farmers hunt pests such as foxes and crows, and soldiers and nobles hunt monsters. Vengeful folk sometimes choose this day to hunt their enemies. The vengeful dead sometimes return as revenants. Possible encounters: scouts, nobles, assassins, revenants.

Festivals make a great backdrop for adventures: they’re one of my most-used adventure elements. They’re a fun way to share your world-building with the players. There’s no better way to showcase a religion, city, or fantasy culture than through its bizarre celebrations.

Festivals often include contests, which give players a menu of optional things to do (what high-Con character can resist a pie-eating contest?). Contests are great because they’re one of the few ways you can introduce an NPC rival who doesn’t immediately die in combat.

Next time your characters head to the big city, have them wander into a festival. Here are 20 festivals, ranging from silly to sinister. I’ve tried to give each celebration a story hook, a contest or two, a threat, or something else for the characters to do.

City Festivals (roll d20):

1. Bonfire festival: A traditional time for dancing, firelight, and the occasional arson. Rival adventuring groups run an anything-goes relay race through the city, with each party member carrying the torch through a neighborhood: the race is lost if the party’s torch goes out. Possible encounters with entertainers, apprentice mages, thieves, and racing adventurers.
2. Festival of gift-giving: Everyone gives a present to a close friend. Merchants are everywhere. It’s easier than usual to find magic items and luxuries for sale, but they’re priced higher than usual.
3. Fortune’s fool festival: (Might instead be named after your pantheon’s trickster god.) Everyone wears masks. A traditional time for romances, assassinations, and practical jokes, each of which are generally accompanied by the festival’s irritating catch-phrase (such as “Fortune’s fool!”). Possible encounters with spies, assassins, entertainers, and slumming nobles in masks.
4. War festival: (Might be named after your pantheon’s war god.) Jousts and tournaments. Celebrants drape soldiers and adventurers with garlands. Anyone who defeats someone else in a joust, tournament, or duel may take the loser’s garlands. Possible encounters with knights, veterans, gladiators, and expert duelists.
5. Magical festival: The city is lit with Dancing Lights, Faerie Fire, Pyrotechnics, and dangerous alchemical explosions. Spellcasters are expected to entertain the citizens with dazzling magic shows. Possible encounters with mages, alchemists, and crowds demanding entertainment.
6. Flower festival: A traditional time for flowers and feasts. Each neighborhood chooses two Champions of Beauty to compete in a city-wide dance contest; the winners get money and their neighborhood gets glory. Possible encounters with entertainers, neighborhood leaders looking for contestants, and beautiful people of all walks of life.
7. Midnight festival: It’s a somber festival with lots of chanting. On the plus side, if the midnight rites are not interrupted, the city is safe from undead plagues for another year! Possible encounters with priests, acolytes, holy knights, and the occasional disruptive undead.
8. Festival of life: (Might be named after your pantheon’s life god.) Clerics are expected to cast healing spells for free on this day; people try to outdo each other in good deeds. Possible encounters with priests, holy knights, and sick and injured people looking for healing.
9. Festival of shadows: Honest folk stay indoors while thieves, vampires, necromancer mages, and the like rule the streets for the day.
10. Storm festival: (Might be named after your pantheon’s tempest god.) Rain or shine (preferably rain), there are war dances, feats of strength and drinking, music contests, and challenges to unarmed combat. Possible encounters with barbarian warriors, wrestlers, and skalds.
11. Day of mourning: A gloomy holiday commemorating a tragic historical or mythological event. Donations are given to worthy causes. Guards impose small fines for laughing, celebrating, wearing bright clothes, and the like. Possible encounters: Nobles giving alms, guards imposing fines, paladins in grim parades.
12. Victory festival: The city celebrates its founding or some historical success in battle. A day of parades, patriotism, and traffic. Parades sometimes turn into riots between rival groups celebrating different victories. Possible encounters: veterans, angry mobs, suspiciously well-armed parades.
13. Brewer’s festival: Beer is free. Traditionally a day for merry-making, drinking contests, brawls, and being robbed while unconscious. Possible encounters: drunkards, human soldiers, dwarves, tavern brawlers, and opportunistic thieves.
14. Topsy Turvy festival: Nobles wear rags and merchants provide feasts for the poor. A randomly-selected prisoner is pardoned, released from the dungeon, and made king or queen for a day, which is usually fine, but there have been occasions where it wasn’t fine. Possible encounters: nobles in rags, feasting crowds, kids bossing around parents, or the King for a Day: possibly a pardoned assassin, political prisoner, or an old enemy of the PCs.
15. Faerie festival: People wear masks and glitter, play practical jokes, and give anonymous gifts. Possible encounters: entertainers, nobles, and visiting faerie folk (good and evil) who are serious about practical jokes and gifts.
16. Hero’s feast: Veterans and adventurers are celebrated, feasted, serenaded, and showered with gifts by those they have helped in the past. Possible encounters: veterans and adventurers of all sorts, generous merchants and nobles, and archpriests who cast Hero’s Feast for worthy heroes.
17. Monster night: People dress up as monsters and wander in torchlit parades. Every year, a few people are killed by real monsters wandering the street undetected. Possible encounters: commoners dressed in realistic monster costumes, werewolves, goblins, and grimalkins (demon cats who can change into panthers).
18. Candle Night: After sundown, relatives who have passed away are remembered, ghosts walk, and death magic is at its greatest power. Carrying a candle is said to attract good spirits and ward against evil ones. The candles are by no means foolproof. Possible encounters: ghosts, zombies, shadows, necromancers
19. All gods day: The city’s business is at a standstill as each religion organizes a procession or parade. There are frequent brawls between the processions of rival faiths. Temples compete to exhibit the most impressive displays of divine magic. Attracts: high priests, holy knights, and parades that frequently devolve into angry mobs.
20. Country Fair: Roll on the Country Fairs table

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I’m working on an ambitious D&D project – something that I’m putting more time into than the Random Dungeon Generator or Dungeon Robber – and today I want to share a particularly Halloweeny piece of it.

Here’s an extra page of the hag entry from some imaginary Monster Manual. What’s this hag’s name? motivation? What creepy activity are you interrupting when you walk into her hut?

Hag PDF

I think it would be cool if every D&D monster had random story prompts like this. I’d like to be able to flip open the Monster Manual to any entry and have everything I need to generate a completely unique, no-prep encounter. Depending on the monster, it could include specifics about the monster’s activities and goals, and perhaps some plausible names and encounter locations as well – a different set of encounter locations for each terrain type, of course. An extra page or so for each monster would do a lot towards making D&D encounters come alive.

It would also bring the Monster Manual up to an unpublishable 800 pages.

By the way, the D&D project I’m working on is NOT an 800-page Monster Manual. My ambitions are grander than that!

Sometimes when I’m preparing for a D&D game, I’ll throw in something crazy and mysterious: an immense stone foot protruding from a cliffside, or a glass mountain with a tiny bird imprisoned inside, or something. I think, “this’ll show ’em the mysterious wonder of a fantasy world! Who knows why this is here? Certainly not me!”

Then, on further consideration, I usually attach a backstory that can be discovered, or a magic power, or something. Because in my heart, I know how things will go down if I don’t.

Here’s how it WON’T happen:

ME: There’s a immense stone foot protruding from the cliffside!
PLAYERS: Wow! minds blown! I guess we’ll never truly understand the mysteries of this ancient land. Oh well, let’s continue north.

Here’s the two possible ways it COULD happen.

ME: There’s an immense stone foot protruding from the cliffside!
PLAYERS: (decent pause to show that they heard me) We continue north.

Or

ME: There’s an immense stone foot protruding from the cliffside!
PLAYERS: Wow, that’s interesting! Is there a giant trapped here? Will it be grateful if I free it? Are there circumstances in which the wall becomes permeable? What spells can I cast on the foot? Let’s do half an hour of magical experiments!

In the latter case, rather than admitting that the stone foot was just a pointless piece of window dressing, I’ll probably on-the-spot invent some payoff for the characters’ investigation: they save a giant; eternal friends with the Flintheart tribe; find the evil oni who imprisoned the giant; etc.

If I went to the trouble to prepare the stone foot in advance, why didn’t I figure out what it was attached to? Why do preparation at all if I’m leaving the hard part for the game, when I’m juggling a million things at once?

This is a design antipattern that I frequently fall prey to, and I see it a lot in published RPG materials too. A suggestive detail is proposed, but there’s no payoff. There’s a stone foot? Why should my players care?

Here are some reasons why I think the “so what” pattern is so common.

Lately I’ve been doing statistical analysis on D&D 5e monsters to see how they’re built, and I’ve learned some interesting things: the DMG monster-creation guidelines don’t work as expected, monster design formulae have stayed stable from book to book, and many of the complexities of the official monster-design process don’t significantly affect its outcome.

Today, let’s come up with simple instructions for creating monsters in line with the Monster Manual, replacing the faulty instructions in the DMG.

Along the way, I think we can streamline the process. The Dungeon Master’s Guide has 9 pages on monster creation. I think we can fit the key rules on one page. Or even a business card. That way, you can create new monsters on the fly, not as a laborious game prep chore.

First of all, to reiterate what I learned in previous posts:

1) real monsters have fewer hit points and do less damage than those created by the DMG chart, and are more accurate

2) there is no significant correlation between any major monster stat (HP, AC, attack bonus) and any other stat. For instance, you might expect that a monster whose AC is high for its Challenge Rating should have lower hit points, attack bonus, or damage output to compensate. That’s not the case. Therefore, we can examine each monster stat separately without having to consider the others at the same time.

attack bonus

Here’s a scatter plot of the attack bonuses of all the Monster Manual and Mordenkainen’s monsters. The black line is the best fit line. (For comparison, the red line is a plot of the Dungeon Master’s Guide suggested attack bonuses.)

As you can see, the scatter plot shows us a nice, straight, easily graphable best-fit line. It works out to almost exactly:

So tidy! It’s almost as if the designers designed it that way! Hint: I think they did. While the DMG graph is arbitrary and inaccurate, actual monster design shows signs of being very carefully put together.

A note about CRs below 1: These complicate things. For the purposes of drawing graphs, think of them as negative numbers instead of fractions: CR 1/2 is really 0, CR 1/4 is -1, CR 1/8 is -2, CR 0 is -3. That’s the way that the linear values on the attack graph work out, and the way I’ve graphed it.

How much leeway do we have to adjust the attack bonus up or down based on our concept? The DMG advice is to adjust as much as you want, you can always adjust the CR later. We don’t want to adjust anything later! We’ll just look at our Monster Manual data and see how much variation there tends to be from the average monster accuracy.

For our attack bonuses, the average variance (which is a statistical calculation for determining how closely grouped numbers are) is low: 1.22. In other words, monster attack bonuses tend to be a little more than one point away from the average. And, as we’ve proved in previous steps, there is no correlation between high/low attack bonus and any other monster stat. So we could say, without doing too much violence to the Monster Manual data, something like, “Based on your monster concept, you may add or subtract up to 2 points from the attack bonus without affecting its CR.”

DC

Difficulty Class is similarly neat. In fact, its graph is nearly identical to the attack bonus (nearly every monster’s DC is their attack +7). In the following scatter plot, blue X’es are DC, and green triangles are attack bonus.

The DC best-fit formula is

Variance is also the same for DC as it is for attack bonus. So on our final rules, we’ll say, “+-2 DC based on monster concept.”

Armor Class

From the scatter plot, Armor Class also looks like a fairly neat linear graph.

Expressed as a formula, this is very tidy: AC = 13 + 1/3 CR

From looking at the scatter plot, you can see that there will be a higher variance in AC than there was in attack and DC. The average variance is 1.65: 50% more than in attack and DC. Therefore, if we say “+-3 AC based on monster concept” we’d be allowing all but a few outliers.

hit points and damage

I did attack bonus, DC, and AC first because they were the easy ones. The remaining values, average damage and hit points, are a bit hairy, because they’re not nice, neat linear graphs.

Here’s one interesting thing about hit points and damage: they have a very strong relationship, especially at low level. Take a look at this chart where I graph median hit points (blue) and median damage x 3 (red).

To me it kind of looks like the average monster’s hit points is intended to be 3x the average monster’s damage (or, to put it another way, each monster should survive exactly three rounds of hits against one of its peers). Given the fact that the D&D designers have frequently mentioned three rounds as their target combat length, this seems plausible.

I admit, something about the chart above gave me pause. At high CR, doesn’t it look like there is an inverse correlation between damage and hit points? At CR 19 and 21, for instance, where damage is high, hit points are low. Did I miss something in my earlier analysis that showed no such correlation?

After looking at this graph, I did a more thorough statistical analysis. A note about my methodology: I calculated p-value for each pair of stats (above-median damage AC vs below-median HP, etc) and also for each stat paired with the presence of major special defenses, major special attacks, and legendary status. No correlation was significant to a value of p = .05. However, some more confident statistician should re-check my values with the Monster Manual dataset, since I’m not really a stats guy, just a guy with access to free web stats tools.

In particular, the seeming correlation we see on this chart, high damage to low hit points, does exist but is statistically insignificant: in the monster population as a whole, of the 227 monsters who deal higher-than-median damage, 101 have under-median hit points and 96 have above-median HP: a difference of 5 monsters either way. But some of the similar monsters happen to be clumped together. For instance, it just so happens that three low-HP, high-damage monsters are grouped together at that big red spike at level 18. I think we just have to say that, at high levels, our data is sparse and unreliable and we are going to have to be careful not to over-model the ups and downs of the graph.

At low levels, though, where we have dozens of monsters per CR (and where D&D play actually happens), I do want to be as faithful to the data as I can.

Take another look at the graph above and then listen to my crazy plan. Hit points and damage x 3 look pretty damn correlated: The correlation may or may not be intentional, but it’s there. Maybe we can come up with one trend line that will describe both hit points and damage?

Here’s that graph again, with my proposed best-fit threading the needle between the hit points and damage line. The data isn’t linear at low CRs, but high CRs are linear enough.

Here are the formulae for average damage and hit points:

Average damage below CR 1: 1, 3, 5, 8
Average damage between CR 1 and 7: 5 + (CR x 5)
Average damage above CR 7: CR x 5

Average hit points: 3x average damage for that CR

Unlike for AC, DC and CR, variance increases quite a bit for hit points and damage as the numbers get bigger. Take a look at this damage scatter plot, which sort of explodes into confetti once we get to the airy heights of CR 10.

For both hit points and damage, we can say Increase or decrease by up to 50% based on monster concept and get all but a few outliers.

Shouldn’t such a big increase or decrease – for instance, bumping a monster from 100 to 50 or 150 HP, or from 30 damage to 15 or 45 damage – change its CR? Perhaps it should, but it doesn’t in the corpus. There are plenty of examples of monsters with wildly varying hit points and damage potential sitting next to each other in the same Challenge Rating – without any other attributes which obviously compensate for the differences. Consider Geryon and the ancient green dragon, both CR 22.

Geryon: AC 19, HP 300, attack +16, damage per round 97
Ancient green dragon: AC 23 (+4), HP 385 (28% higher), attack +15 (-1), damage per round 151 (55% higher)

It’s wacky, but it’s how CR currently works. And I’m trying to describe CR here, not improve on it.

We need to do one other thing before we leave the topic of damage: on our new, improved monster-creation rules, we have to explain our average damage calculations so that people can turn each monster’s raw damage total into arbitrarily complex sets of attacks, including spells, area attacks, and limited-use abilities. This will be hard to explain concisely and clearly, but let’s take a shot at it.

Here’s a first draft: “Damage: This is the average damage that a monster can do each round during the first three rounds of combat. Assume 1) it always uses its most damaging attack(s) or spell which hasn’t yet been exhausted; 2) all area attacks target 2 enemies; 3) auras and similar traits target one enemy per turn; 4) variable-length effects like Swallow last one turn; 5) all attacks hit; 6) all opponents fail saving throws. Based on the monster concept, the monster’s damage may be dealt in one attack, or be divided between multiple attacks and/or legendary actions.”

This encapsulates the rules as described in the DMG. There’s one problem with these rules though. They’re facing the wrong way. They’re the instructions to take a Monster Manual creature and turn it into a single damage number. We need the instructions to take a single damage number and turn it into a Monster Manual creature. How about this:

Damage: This is the damage budget for all the monster’s attacks. Limited-use (daily, recharge, or situational) attacks do 4x the damage budgeted. Multi-target attacks do ½ the damage budgeted. Limited-use multi-target attacks do 2x. All other damage sources are 1 for 1, including at-will and legendary single-target attacks, auras, reactions, and variable-length effects like Swallow. If a monster has several at-will options (such as melee and ranged), the lower-damage options are free.

Here’s an example of how you could spend a damage budget on several attacks. Let’s say you imagine a fire-using spellcaster. You give her a 1/day fireball for 28 damage (spending 14 points of the damage budget); an at-will Fire Blast against one target that does 11 damage (spending 11 damage); and, to round it out, a 3-damage dagger attack (free because it’s an at-will option that does less damage). That would cost us 25 damage: right on the nose for a CR 4 creature. But because of the variance in damage, she could be pegged as anything between a strong CR 2 (on par with a pentadrone) and a very weak CR 10 (on par with a CR13 rakshasa).

monster traits

Nearly every monster, except for beasts and some boring humanoids, have some “schtick:” some special trait that makes them unique. It’s hard to quantify these. The DMG tries: it offers two pages of traits, listing the modification that should be made for each to the effective HP or AC. Most of these minor modifications, by the DMG rules, are worth a fraction of a CR. Given the wild fluctuations in power of same-CR creatures, this is illusory precision (I talk more about that here).

We can test common and seemingly powerful traits like legendary resistance and magic resistance and in almost all cases, the presence or absence of these traits has no correlation to higher or lower monster statistics. Therefore, they are not visibly affecting a monster’s CR. The only verifiable exceptions, as I mentioned here, are regeneration (which has a negligible but real effect, reducing some monster HP a by a few percent) and possession (which has a large effect, halving hit points) and possibly damage transfer. I think we can turn these three cases into a general rule: you may reduce damage-avoiding monsters’ hit points by the amount of damage you expect them to avoid over 3 rounds of combat.

what about saving throws?

I think we can improve on the original DM’s Guide rules in another way. The DMG chart has values for proficiency bonus, AC, HP, attack, damage and save DC. Monsters also need to make saving throws. Really, what we want to know is, “what does a saving throw look like for a monster’s good stat?” and “what does a saving throw look like for a monster’s bad stat?”

The bad saving throw is easy. It can be anything based on the monster’s story! For instance, the tarraque’s Dex save is +0.

For the good saving throws: calculating this was an afterthought and I didn’t feel like manually entering the good saving throws for the entire Monster Manual. I decided to see if a sample would be enough. I manually entered the best saving throws of all of the monsters up to page 84 of the Monster Manual, right before the start of the Dragons entry. I also added the ancient red dragon, so I could get the good saving throw of the strongest non-thought-experiment monster in the game. Based on how the data looked, I’d see if I had enough information or if I needed more. Here’s what I got.

This data is clearly tightly-grouped and linear: I don’t need any more sample to see that. It’s a hair off of 1 point of saving throw bonus per 2 levels. This formula will always keep us within about half a point of the real value:

3 + 1/2 CR

And the eye test tells me that variance is very low. I’d estimate it at +- 2. That is to say: the saving throw bonus column is equal to the Attack Bonus column minus 1.

By the way, 3 + 1/2 CR also works for a monster’s good skills!

putting it all together

OK, now we have everything we need to make a complete chart replacing the one in the Dungeon Masters Guide! This will give us out-of-the-box numbers that closely match the Platonic ideal of a 5e monster of any CR. Just tweak according to taste, add a special ability or two, and you are good to go. This is something you can do live at the table, not as part of your game prep!

Here’s the finished chart:

And here’s a PDF that you can print out and put in your DMG.

And if you want something really compact, here’s the important rules on a business card:

Next up in the monster math series: Monsters of the Multiverse Math!

I’m pretty close to finishing up my monster design guidelines based on reverse-engineering the Monster Manual. Before that, though, I want to comment on an interesting episode of DM’s Deep Dive in which Mike Shea (Sly Flourish) interviewed D&D lead rules designer Jeremy Crawford about monster design.

Mike asked Jeremy about the table in the DMG for homebrewing monsters. It’s public record that I have my doubts about that table. Jeremy provided this interesting fact: apparently, the canonical formula for determining monster CR is encoded in an internally-used Excel spreadsheet. (We’ve seen this spreadsheet in action in the Mike Mearls Happy Fun Hour.) The table in the DMG was made after the spreadsheet, and was an attempt to reverse-engineer and simplify the spreadsheet’s formulas for DM’s home use: it’s not used as part of the process for creating for-publication monsters.

My research indicates that while D&D monster stats are internally consistent and carefully designed, their power levels don’t line up well with the DMG chart. This leads me to believe that the spreadsheet does what it intends to do, while the DMG chart does not.

I invite you to ponder this further mystery from the Deep Dive podcast:

In the podcast, Jeremy Crawford talked about how the D&D team approaches what he calls “action denial” attacks: paralysis, charm, etc. This is something I’ve wondered about. My initial research suggested that these attacks didn’t have much of an effect on CR, which I though was strange: taking out a combatant for a few turns seems like it should be a powerful ability.

Jeremy used paralysis as an example to illustrate the team’s approach. First, find the lowest-level spell which inflicts a condition. For paralysis, that’s Hold Person. Next, you translate that into damage by finding the damage output of the simplest pure-damage spell of that level. Hold Person is level 2, and its comparable damage spell is Scorching Ray, which does 6d6 (21) damage. Thus, the ability to paralyze is worth 21 “virtual” damage for Challenge Rating calculation purposes.

I see the logic in that, but it doesn’t scale the way I’d expect it to. If you’re fighting four opponents, I’d expect the ability to keep one of them paralyzed to be worth, say, 33% extra virtual hit points (the hit points you won’t be losing to the paralyzed opponent) – or some similar scaling benefit. If the ability is expressed as flat damage, 21 hit points damage is dominant at low levels and negligible at high levels.

And indeed, when checked against monster data, it doesn’t seem as if monsters are balanced exactly as Jeremy describes. Check out the chart below. This includes all ten CR-5 or lower monsters with a paralysis attack: the carrion crawler, chuul, ghoul, ghast, grell, pentadrone, mummy, revenant, thri-kreen, and yeti. (Above CR 5, the 21 virtual hit points of paralysis would rarely be relevant to CR because monsters generally have a more damaging attack options.)

In this chart, the blue diamonds represent the average damage output of a monster of each CR from 1 to 5. The red X’s represent the base damage output of paralysis-inducing monsters – without the 21-point “Crawford bonus.” As you can see, the paralyzer damage is very close to average monster damage.

The green triangles represent the average damage of paralyzers, once you take the 21 points of “virtual damage” into account. As you can see, adding this would skew monster damage way too high – doubling their effective damage in most cases! If this damage were really being taken into account the way Jeremy describes, all these low-level monsters would have to have very low-damage attacks – a ghoul with a claw doing 1 damage, for instance – to make room for all that virtual damage.

This is one of those unaccountable situations, like many others that we’ve discovered while investigating how monsters are built, where the WOTC instructions for building a monster don’t match the monsters we see in the manual.

My best guess for why this is: playtesting. It’s possible that monster stats started off skewed and exception-ridden. How could they not? It’s an incredibly complicated system. But then through the public D&D Next playtest, the NDA playtest, the internal playtest, and the good intuitions of the designers themselves, the proud nails were hammered down. Monsters were adjusted until they felt right. The tyranny of the spreadsheet was overthrown by humans, or at least reformed into a constitutional monarchy. And so, while the designers of D&D may be still using an occasionally flawed formula to initially prototype their monsters, they’re compensating for the Excel spreadsheet’s failings in later steps of design.

It’s interesting to compare the designers’ intent (as evidenced by what we know of their monster-design process) to the final product (the monsters in the rule books.)

The intent is to account for everything in a monster’s CR. Hundreds of monster traits are weighed to the fraction of a CR. Changing one stat has a ripple effect on other stats. As Jeremy said in the podcast, they’re still using the same Excel spreadsheet that they’ve been using for five years. I’m a programmer and I know what that means. Complication is added to complication, all adding up to the illusion of precision. No one really knows how it works anymore: look how hard it is to reverse engineer (see that DMG table I’ve been complaining about). From this end of the process, monster design has a baroque, stately, creaking majesty.

The final product, when analyzed, is simple, flexible, and streamlined. Challenge Rating gives a broad bell curve of possible hit points and damage outputs. Tweaking one number doesn’t affect another. A monster’s traits and special abilities have no significant, measurable effect on its Challenge Rating: every monster gets its schtick and they all sort of balance out. From this end, monster design appears to have a flexible, easygoing, organic solidity.

This is a common pattern in tabletop game design. Things start complicated. The more they’re used at the table, the simpler they become. I think Jeremy and the rest of the D&D team are geniuses, but their real genius lies in knowing and respecting the value of playtesting.

Next: the final rules for making monsters

In my last post, I demonstrated, via too many charts, that the monster-creation math in the 5e Dungeon Master’s Guide doesn’t match the monsters in the Monster Manual. As an example: the average CR 1/4 monster has 13 hit points. The DMG suggests that they should have 43 hit points. Imagine your level-1 party mobbed by skeletons with 43 HP each instead of 13!

In my next post, I’ll be offering a chart to replace the one in the DMG, which lets you create monsters on the fly: monsters which are about as dangerous as you’d expect based on their Monster Manual cohort.

In between my last post and my next post, though, we need to do a little more analysis. Do legendary monsters skew the math? And has the math changed in recent D&D monster books, such as Mordenkainen’s Guide?

legendary monsters

Legendary monsters are the conceptual descendant of Fourth Edition’s “solo monster”: a single monster designed to challenge the whole party. If I remember right, solo monsters had 4x the hit points of a standard monster of their level. Are 5e’s legendary monsters’ HP similarly inflated?

There’s not much overlap, but it’s pretty clear that legendary and standard monster HP both fits on the same trend line.

I won’t show all the charts here, but I will tell you this: legendary monsters have basically the same armor class, hit points, attack bonuses, and save DCs as their non-legendary counterparts. The only chart that looks interesting, at first blush, is damage:

Legendary damage looks higher, right? But actually I think something else is going on. Dragons. They’re an outlier, with high stats in general: both high hit points and damage for their CR, plus a host of beneficial traits such as Legendary Resistance. Let’s break the legendary creature damage into dragons and non-dragons.

There are not a lot of non-draconic legendary monsters in the Monster Manual, but their damage totals (the green triangles) are on the same trend line as the standard monsters. The dragons form their own trend line, hovering threateningly over the other monsters.

So, in general, legendary monsters have the same stats as any standard monster. How is a legendary monster different?

Legendary monsters are more interestingly built. They have off-turn legendary actions. They may have lair actions. Some, but not all, have Legendary Resistance, so they can’t be shut down with one spell. But, apart from the dragons, they have the same hit points, damage per round, and other game statistics as any other monster of the same Challenge Rating.

Mordenkainen’s Guide

Our charts look plausible so far, but we’re hampered, especially at high level, by low sample size. Enter Mordenkainen’s Guide. Mordenkainen’s is notable because it’s chock full of high-level and legendary monsters: it contains as many CR 8+ monsters as the Monster Manual does, doubling my sample size for high-level monsters. (There are, of course, more monsters in Volo’s Guide and other sources, but I haven’t charted them yet.)

But are monsters in the Monster Manual and Mordenkainen’s comparable? Has monster design changed drastically in the four years since the Monster Manual was released?

First of all, how do Mordenkainen’s Guide hit points look compared to Monster Manual hit points?

Pretty much the same. In this graph, I’ve broken out the hit points of legendary and nonlegendary monsters from Mordenkainen’s so we can check our work from above: legendary monsters don’t have more hit points than other monsters. In fact, if anything, they have slightly fewer. Furthermore, the general hit point trend is the same for Monster Manual and Mordenkainen’s monsters.

I’ll skip over some other uninteresting charts: the long and short of it is, Mordenkainen’s Guide monsters have roughly same ACs, attack bonuses and save DCs as Monster Manual monsters of equal CR.

I do want to take a closer look at monster damage from Mordenkainen’s, however.

Here I’m graphing average Monster Manual damage/CR against Mordenkainen damage/CR. I’ve broken the Mordenkainen data into legendary and nonlegendary just to confirm that there is no significant difference between them. Mordenkainen damage is on par with Monster Manual damage. (Except for that spike at CR 18: that’s the sibriex, possibly the highest-damage-per-round monster in D&D except the tarrasque.)

Nevertheless, there is one statistical difference between the Monster Manual and Mordenkainen’s Guide damage that this chart doesn’t show.

The *standard deviation* – distance from the average – is much higher in Mordenkainen’s.

For the 75 CR 8+ monsters in MM, and the 75 CR 8+ monsters in Mordenkainen’s, the average standard deviation in the MM is 16, even including dragons, and in Mordenkainen’s it’s 21.

That means that high-level Mordenkainen’s Guide monster damage is 30% farther away from the norm compared to the Monster Manual. There is a little less predictability in how powerful a monster is given its CR. This may be a function of the increased complexity of the newer monsters. It may also be a sign that the game’s designers don’t care as much as they used to about adhering very closely to monster-creation guidelines. There’s more art and less math in Mordenkainen’s Guide.

Art is good. That said, there’s something to be said for consistency. Therefore, as a public service, here’s some monsters in Mordenkainen’s to watch out for if you want to avoid a TPK that surprises everyone, including the DM.

The Sibriex: this monster can drop 200 HP a round at CR 18, just about double what you’d expect from a CR 18 monster.

The Duergar Despot, CR 12: the despot fires the equivalent of two full-scale Lightning Bolts per turn. He can do 72 HP of damage to each PC he hits, which, in enclosed tunnels, may very well be all of them.

The Star Spawn Mangler, CR 5: on round 1 it can do 90 damage, all to the same enemy. A level 5 fighter may have 45 HP. DM and player alike may be surprised to see that front-line fighter not only dropped, but killed, during a surprise round, against an equal-CR opponent. Compare the Mangler’s damage to Geryon, the CR 22 legendary duke of Hell, who can do 77 damage on round 1. (Note: On round 2, the Mangler is useless. That’s how it’s balanced.)

Well, that ends my deep dive into… wait, you know what? let’s look at just one more delicious chart. Maybe two tops.

Challenge Rating and monster traits

One of my findings that surprised me the most from my examination of the Monster Manual was that a monster’s resistances and immunities don’t affect its hit points and damage. The DMG claims they affect hit points, and you can certainly find some MM monsters, like the wraith, who have lots of resistances and who have lower than average hit points. But those are balanced by other high-resistance high-hit point monsters.

Let’s look at the hit points of monsters with a lot of resistances and immunities in Mordenkainen’s.

There is no significant difference between the hit points of the general population and those monsters with 8 or more resistances and immunities!

There must be some traits that affect monster stats. Let’s look at regenerating monsters. We’d expect them to have lower hit points.

Finally, a correlation! Monsters with regeneration have lower max hit points than the general population – as we’d expect them to, since regeneration 10 over 3 turns should be worth 30 hit points.

Here are the monster traits which seem to have any noticeable correlation to stats:
Regeneration: Hit points lowered by 30 or more
Possession: Hit points halved
Damage transfer: With no degree of confidence because there are so few examples in either book, this may lower hit points or damage.

And that’s all I’ve found so far that makes any difference. The abilities to stun, charm, paralyze, or petrify don’t seem to make a difference to HP or damage, nor does magic resistance, legendary resistance, superior invisibility, or any of the other traits listed in the DMG – at least not enough to move the needle. That will all be useful information when we get to designing monsters.

I hope you enjoyed my descent into statistical madness! I want to point out here what I hope is obvious: I think 5e is great and I’m not looking to ruin anyone’s fun by examining its math. I just like figuring out how good things work, and, if possible, making them better.

In a few days I’ll deliver that much-promised build-a-monster-on-the-fly chart.

(Edit: In fact, next I talk about Jeremy Crawford on monster design)

While messing around with monster creation, I started comparing 5e Monster Manual creatures with the 5e guidelines for creating monsters (DMG page 274). Based on my number crunching, it looks like the DMG’s central monster creation chart, “Monster Statistics by Challenge Rating”, isn’t in line with the Monster Manual, and if you try to follow it you will get monsters that don’t look much like Monster Manual monsters.

This may be widely known and only new to me, but I haven’t found anything definitive or official on it. A fairly cursory search only turns up a few argumentative message board discussions and some pretty good Howling Tower posts (such as https://koboldpress.com/howling-tower-monster-stats-part-2/ where Steve Winter graphs the discrepancies but backs off the conclusion that the DMG chart is incorrect.

In this post, I’ll try to show the data that suggests to me that the chart is wrong.

Note: the process of creating a monster stat block is long and convoluted: according to the DMG it’s a 20-step process (!) and one of the steps involves executing another 4-step process detailed elsewhere. So there’s lots of room for error, and I could have a lot of things wrong. But the basic process is: figure out the monster’s Defensive CR, which is primarily determined by HP but modified by AC, resistances, and some traits; figure out its Offensive CR, which is primarily determined by average damage over three rounds of combat, modified for burst damage, area of effects, and various traits and abilities, and also by attack bonus or spell save DC; and then average the offensive and defensive numbers to get the final CR.

Hit Points

The first clue that the DMG​ chart is wrong is in the hit points column of the chart. According to the chart, for instance, a CR 1/4 monster has 36-49 HP. However, let’s look at some CR 1/4 monster hit points. Boar, 11 HP. Goblin, 7 HP. Skeleton, 13 HP. Wolf, 11 HP. The CR 1/4 monster with the highest HP is the mud mephit, with 27 HP, still significantly less than the low end of the DMG-suggested hit point range.

Here’s a chart of the DMG-suggested Hit Points versus the average hit points per level from the Monster Manual: purple bar is the DMG’s Hit Point recommendations by CR, blue bar is the actual average HP from the Monster Manual.

That weird dip at CR 18 is because the demilich is the only CR 18 monster. And in fact, there are so few data points above level 10 that any analysis above level 10 should be taken with a grain of salt. Even ignoring the demilich and the dearth of high level data, you can see that the Monster Manual Hit Points skew way low.

The DMG monster creation rules have lots of adjustments to be made: monsters with lots of resistances and immunities are to have their “effective HP” adjusted upwards; and defensive abilities, such as damage transfer, regeneration, or magic resistance also adjust the effective HP. However, on examination, these adjustments don’t actually account for the extra HP in the DMG chart. In fact, they don’t do much at all. Examine the following chart:

In the chart above, “mm no defenses” means those monsters with few resistances and no significant defensive abilities. You’d expect these monster to have the highest hit points. “mm low resistance” are the monsters with few resistances, whether or not they have defensive abilities. “mm high resistance” means those monsters with more than 3 resistances or immunities: you’d expect these monsters to have the lowest hit points. (Many of these bars are broken because there are CRs at which there are no monsters which meet these qualifications.)

In fact, below level 12 – where we have enough data points to do reasonable analysis – there are no significant hit point differences between monsters with high special defenses/resistances/immunities and those without. At high levels, it is plausible that high-immunity monsters may have lower hit points, though we really need more data points to be sure. However, the overall trend lines are clear: none of these groups of monsters has anything like the hit point totals recommended in the DMG – even the no-defense brutes.

Conclusion: In the Monster Manual, hit points are much lower than the values presented in the DMG. Furthermore, special defenses, resistances and immunities don’t seem to be related to hit points.

Armor Class

Now let’s add armor class into the analysis. In the DMG, hit points and armor class are both used to determine “defensive CR” so perhaps it doesn’t make sense to analyze one without the other.

First of all, a simple analysis of real Monster Manual AC versus expected DMG AC.

Apart from high levels, Monster Manual and DMG ACs are close: usually within a point of AC.

Could Armor Class solve our Hit Point problems? Perhaps low-AC monsters have proper DMG Hit Point values?

Here is a chart of the average hit points of monsters grouped by AC.

“Low ac hp” is HP of the monsters with AC lower than the DMG AC value. You’d expect these guys to have high hit points. “High ac hp” have higher than average AC and theoretically should have lower than average hit points. “Target HP” are the monsters whose AC exactly matches the DMG AC expectations.

As you can see, below level 11, there is no significant difference in HP between those monsters with high and low HP. Above level 11, things are swingy as usual because of fewer data points, but there is no obvious through line that suggests that there is any relationship between AC and HP.

Conclusion: In the Monster Manual, AC values are on par with those presented in the DMG. Hit points and AC do not seem to be correlated in any meaningful way.

Damage

It takes quite a few steps to calculate a monster’s “average” damage according to the instructions in the Monster Manual. The process is: figure out the average damage for the first 3 rounds of combat. Assume that all monster attack hits and all hero saving throws fail. All area attacks hit two people, and all ongoing effects (like being swallowed) last for one turn. Effects like Charge or Pounce happen once.

After all these calculations, here are the Monster Manual average damages by CR, compared to the DMG expectations.

(The gap in the blue line is for the demilich, the only CR 18 monster, whose max damage is hard to calculate.)

The Monster Manual damage is fairly close to the DMG expectation, though generally 10% to 20% low. This is odd: Monster Manual hit points are too low according to the DMG rubric, and damage is low too? It seems as if Monster Manual monsters are just weaker than the DMG suggests. But let’s do some further analysis to damage.

Perhaps monsters have a higher “effective hit points” because of special attack modes. If this is the case, those monsters with special attack modes should have lower hit points than simple monsters. To test this, I’ll separate out those monsters with powerful attack modes that don’t do direct damage, like charm, stun, paralysis, and instakill abilities.

As usual, below level 11 where we have the most data, there is no damage difference between monsters with and without special attack modes. At high levels, there are variations, but there is no clear winner.

Maybe there is some relationship between damage and hit points? Perhaps monsters with lower hit points do higher damage, and vice versa?

To test this, I’ll graph the damage dealt by below-average-HP monsters and above-average-HP monsters separately.

Again, below level 11, there is no difference at all between the damage output of beefy and glass-jawed monsters, and at high levels the correlation isn’t clear. If anything, there may be a slight reverse correlation with beefier monsters doing more damage.

Conclusion: The damage output of Monster Manual monsters is slightly lower than the DMG expectations. It’s not correlated with special attack modes or with hit points.

Attack bonus

We have another important value to look at: attack bonus. How do the monster manual attack bonuses compare to the DMG values? And do they correlate to any other monster stats?

First of all, the attack bonus numbers:

Attack bonuses are WAY off. Monster Manual values are consistently too high compared to DMG values throughout – as much as 5 points too low at level 24 (+12 vs +17).

This is starting to make sense. I think the DMG values are an early draft of the monster formulae. I bet that at some point, the developers decided that they needed to raise the accuracy and lower the damage of monsters, aiming for the same total damage. The DMG chart never got updated.

While we’re here, let’s just check for a few more correlations. Do high-accuracy monsters have lower damage output, or have fewer hit points? My guess is no, since we’ve hardly found any correlations yet.

Not only does attack not balance anything out, there may be a reverse correlation: hi-accuracy monsters also tend to be slightly higher-damage and higher-hit point than normal. In other words, within a given CR, some monsters are better all-round than others.

Conclusion: Attack bonus in the Monster Manual is way lower than in the DMG chart, and doesn’t correlate with any other monster attributes.

Save DC

Since we’ve come this far, we might as well look at the last column in the DMG chart: save DC.

The save DCs in the Monster Manual are quite different from those in the DMG chart. The DMG DCs are much flatter, ranging from 13 to 23, while the actual DCs range from 10 to 24. I don’t think I need to do a lot of analysis on DCs.

Now what?

It seems clear to me that the Monster Statistics by Challenge Rating isn’t the up-to-date version of the monster creation formulae. I bet it was accurate as of some iteration of D&D Next and never got fully updated.

It’s also apparent that there is not a lot of correlation between any monster stat and any other stat. All the complicated DMG steps involving adjusting and averaging don’t actually hold up to examination when we look at the Monster Manual monsters. The actual process seems to be something like

1. Start with appropriate numbers based on CR
2. Adjust any stat or two up and down, and add any trait or feature, based on story. Don’t make any further adjustments.

Which is great for us! This two-step system is way easier than the 20-step DMG version. We can even do it on the fly! All we need is an accurate CR-to-statistics chart.

Give me a few days: I’ll try to come up with a new monster-creation chart that will match Monster Manual monster math, and that is small enough to fit, say, on a business card.

In the meantime, here is a copy of the monster-stat TSV file I used to generate these tables. Please feel free to validate the monster stats, validate or invalidate my calculations, correct my assumptions, prove me wrong, or whatever else you want to do with this stuff.

Next: more numbercrunching: we look at Mordenkainen’s Guide