This is part 4 of 5 of the series: Custom Monster Building for Beginners

Monster Building 202: The D&D Monster Monster Building Lab Practicum

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Look, it’s no secret that my relationship with 4th Edition was (and still is) complicated. In some ways, I really hated 4th Edition. But I also loved certain aspects of 4E. Most notably, I loved the Monster Manuals. The creatures in 4E were imaginative and interesting and new. In the first Monster Manual, demons were half-elemental fiends, elementals were hybrid creatures like tornadoes filled with shards of rock, angels were just awesome, the lamia was actually a collection of beetles dressed up like a person, and there was a thing called a rimefire gryphon. I remember listening to James Wyatt explain the 4E Monster Manual to Mike Mearls and Dave Noonan before it’s release and he was so f$&%ing excited about all the amazing, creative things they were doing. He was so passionate. Because they had consciously decided not just to fill the Monster Manual with the same old rehash of the same old monsters.

But beyond that, there were two really neat (and related) things that the 4E Monster Manual did that were incredibly useful. First, the idea of monster roles.

See, as I’ve noted in previous articles about building combat encounters, a monster isn’t just a set of stats. A monster is a strategy, it’s a way of fighting. And understanding that strategy is the key to building a really good combat encounter. Well, monster roles were central to that idea. Every monster had a stated role: it was a defensive monster, it was an ambush monster, it was a damage-dealer, it was a support monster, whatever. And that told the GM how to use it. Ambush monsters need ways to approach the PCs unseen. Defensive monsters pin PCs down and benefit from chokepoints. Sniper monsters need terrain to protect them from approach. And so on. These roles became especially useful in team-ups. A defensive monster could protect a sniper. A damage dealer could provide a distraction for an ambush monster. And so on.

BUT, that’s only half the story of monster roles. The other half of the story is that the roles were cues to the designers. So, when a designer decided to build a defensive monster, that told him that the monster was going to have to be hard to hit and be able to maintain some control over the battlefield. The designer built the monster to do just that. It had reactions to keep PCs from getting away, for example. Or maybe it could take damage for its allies. Or interpose its shield to protect another creature. And it had a high armor class so it was hard to hit. And enough hit points to take a beating.

Every monster was built to do something specific. And then it told the GM exactly what that specific thing was. For a GM who cares about the quality of their combat encounters, that s$&% is in-f$&%ing-valuable.

The other thing that 4E did was to give you some variety with your monsters. So, you didn’t have one goblin, you had several. You had the sniper goblin, the lurker goblin, and spell-slinging goblin. Now, obviously, that works really well with roles and team building. But it could have presented a problem. After all, when you have five different goblin stat blocks, what is it that – mechanically – makes them all goblins. What makes them feel like members of the same race?

Well, the reason I said it COULD have presented a problem is because the designers were actually very smart. There were certain Traits that unified all goblins. Or all orcs. Or all ogres. They shared some common abilities and their ability scores were pretty similar. And beyond that, most abilities were flavored by both role and race. So a goblin ambusher did things differently than a bugbear ambusher or an orc ambusher.

I really loved that s$&%. Because, me, as much as I love a good story – and I really do, you can’t deny I have a keen understanding of narrative building and the freedom that a good RPG brings – I also love the solid gameplay experience that is a well-build combat. In gaming, as in all things, I’m pretty much the most moderate of moderates.

Now, roles disappeared from the game. In addition, the idea of statting up creatures differently for different roles also disappeared. At most – AT MOST – you get three versions of a creature. The creature, the leader, and the spellcaster. To be fair, they are well-designed and they follow of the philosophy of race plus role defines stat block, but your basic monsters have to fill all the combat roles and the leaders generally fill the same role plus one support ability. And the spellcaster is just a hodgepodge of spells .BOOOOORRRRRIIIIINNNNNNGGGG.

Because, here’s the dirty little secret I discovered. 5E has everything you need to build monsters at almost exactly the right power level AND also to design to specific combat roles and tactics. That is, you can design a monster for a very specific purpose in your game if you know how to do it right.

Last week, we analyzed every single number that goes into making a monster. Basically, we took monsters apart. Now, it’s time to put monsters together. I’m going to teach you how to build a monster. And I’m going to teach you how to do it in a much more sensible way than the DMG does. Moreover, we’re going to take a role-based approached. Now, don’t worry, I’m not going to go so far as to say we’re going to design rules for soldiers and brutes and artillery. We don’t need to do that. What I mean is that we’re going to START with the question “what the hell is this monster going to do in the game?”

Recording Your Creation

Before we begin, let’s take just a moment to talk about how you actually record your creation. You might have noticed that I’ve built up a template for creatures here on my website. It isn’t precisely the same as the D&D style, but it is inspired by the D&D style. If you want to use it, it works in MS Word 2013. It’s all yours. Don’t get excited. It isn’t a form. It doesn’t do math for you. Nothing like that. It’s just a document you can overwrite.

There’s also a web based solution I haven’t tried yet. A frienemy recommended it, so I’ll share it with you. I think you need to be comfortable in HTML to use it. It’s Valloric’s Statblock5e.

Of course, you can record your creation any way you want. It’s all the same, really. And the format doesn’t matter. What matters is how awesome your monster is.

Okay, let’s build a monster.

Edit: A Crazy Warlock down in the comment section below shared this awesome downloadable tool for building monster stat blocks. Check it out and consider donating to the folks who made it if you like it. I will personally check it out this weekend. If it’s good, I am going to make sure the world knows about it and throw them some cash.

D&D Monster Make from The Genius Inc.

What the Hell is this Monster For?

The first thing you want to know before you start building your monster is what the monster is for. And this is the first place I deviate with all the other f$%&wits giving monster building advice with their “concepts” and their “hooks.” The backstory, the fluff of a monster? It’s secondary. Anyone who tells you to start with a compelling concept or story is full of horses$&%.

It’s not BAD to have those things. They can help inform the design. But you don’t HAVE TO have them. If you design a mechanically compelling monster, you can usually figure out its story later.

But what you absolutely DO need to know is what you’re using this monster for. Even if you’re just designing a monster for fun or to share as part of some well-intentioned but misguided “I’m going to share a custom monster every f$&%ing day on my website for a month thing,” you need to start with the in-game purpose for the monster. And that boils down to three things.

First, what Challenge is the monster? And I don’t mean “approximately what level of difficulty are you going to try to shoot for if everything works out okay and the planets f$%&ing align.” I mean what Challenge Rating is your final creation going to be. There’s no mystery here. There’s no chance. You are going to build a monster to fit a specific challenge. End. Of. F$&%ing. Story.

Second, how does the monster fight? Is it aggressive? Is it hard hitting? Accurate? Defensive? Does it suck up damage like a sponge? Is it fast? Does it fight in large numbers? Is it a loner? When you put this monster into a fight, what is it going to do? And how is it going to do it?

So, for example, I’ve been talking about a couple of different types of monsters. I want to populate my a temple to the Mad Monkey God. So, I need some little tribal humanoid lemur people. And I also want a big, brutal, ape monster.

I see the lemur people as scurrying. They are fast, they are mobile, they are dodgy. They run circles around the party and use guerilla tactics. And the ape monster is big and tough, sure. But I don’t want him to be the typical hard-hitting ogre. I want him to also be fast. Not scurrying, but surprisingly agile and athletic. And he hits hard.

Now, we’re actually going to make the lemur people even more interesting, because I’m going to stat up several different lemurians. Sure, I could just make a lemurian with a ranged attack and a melee attack and be done with it. But I like the idea of different breeds of lemurian that fill different combat roles. And that means, they are also going to appear in a group.

So, for the lemurians, I want a skirmisher type that relies on scurrying melee attacks. And I want a ranged attacker that throws things and relies on scurrying out of danger. And then, for something really interesting, maybe I will add a tougher protector lemurian. That lemurian likes to scurry around protecting and supporting his allies.

Now, my adventure is level 4, which means my encounters can support anywhere between 500 and 2,000 XP, but should average about 1,000 XP total per encounter. That means, if I have a group of 3-6 creatures, each creature needs to be worth about 100 XP (remember, when we have 3-6 creatures, we effectively double the XP for difficulty purposes). And that tells me my lemurians need to be Challenge Rating 1/2.

My ape monsters are probably going to appear alone. But I don’t want them to be “bosses.” Just creatures that live in the temple. So I’ll make them Challenge 4. They appear alone, but they are just an average encounter.

So, let’s work through the process.

Step 1: Challenge Rating

The first step in the process is to decide what the actual, final Challenge of the monster you’re creating is going to be. As I noted, I don’t believe in the DMG approach of f$&%ing around and then seeing what kind of Challenge you end up with. Challenge is just too f$&%ing important to leave to chance.

More importantly – because you might have noticed that I already technically answered the Challenge question – all Challenge is not created equal. As we discussed in our Dissection Lab, Challenge is actually made up of two components. The monster’s FINAL Challenge is the average of its Offensive Challenge and its Defensive Challenge. And that is such a powerful fact that I’m furious that the DMG is almost dismissive of it. That simple fact is EVERYTHING.

Suppose you decide to design a CR 4 monster like a giant Lemurian Behemoth. Hypothetically. You COULD assume that its Offensive Challenge and its Defensive Challenge must both be 4, right? And that’s true. The average of 4 and 4 is 4. But you know what else averages out to 4? Well, 3 and 5. Or, even 2 and 6. Or, 8 and 1/8. DO YOU UNDERSTAND WHAT THAT MEANS?

What that means is that, when you create a creature, you have two knobs: Offensive and Defensive. You can dial the Offensive knob UP a step if you dial the Defensive knob DOWN a step. For example, if I want my big Lemurian Behemoth to be an aggressive damage dealer that’s easy to hit? Maybe, I build him for Defensive Challenge 3 and Offensive Challenge 5.

Now, a small variation goes a long way. And that’s a good thing, because if you make a creature that’s TOO divergent (like that 8 and 1/8 thing), the results can get … ermm… messy. Especially if you dial the Offense up. A high defense creature lasts longer, which makes him potentially boring because he’s hard to hit and takes a lot of hits to go down. But a high offense creature turns PCs into chunky salsa. So I personally try to keep everything within one or two steps. But even that small variation can do you a lot of good.

We’re going to stick with just two running examples right now. The Lemurian Darter (which is just the basic lemurian combattant) and the Lemurian Behemoth. We’re going to save the Lemurian Protector (that’s the defensive one) and the Lemurian Pelter (that’s the rock-throwing one) because I am actually going to show you a cool trick with them.

Step 2: Traits (and Other Things)

Every creature needs at least one cool Trait that says something about what that creature is about. There’s a small number of creatures in the Monster Manual that get by with a flavorful attack. But most creatures should have something that speaks to their particular style of fighting. Or just existing in the world. A Trait is a way to make the creature more than just a pile of stats. For example, recently, my players encountered an imprisoned ogre that had been enslaved by a brutal tribe of Hell goblins. So, I added this Trait.

Cowed. Erug’s spirit has been broken. He suffers disadvantage on Intelligence, Wisdom, and Charisma saving throws to avoid being charmed or frightened. If Erug cannot see or hear any of his allies and he is not in combat, creatures making Charisma (Intimidation) and Charisma (Persuasion) checks to influence Erug receive advantage on those checks.

It kind of makes the ogre this pitiful little broken puppy. Without his taskmasters yanking on his choke-chain, he’s helpless and he can be pushed around by anyone. He’s just terrified of anyone hurting him anymore. Sad, huh? Well, my players didn’t manage to discover him on his own. So the goblins just turned him loose and they hacked him to bits while he slammed away at them, too terrified to run for his life.

But I digress. I know it seems weird to jump right into Traits, but there’s a good reason for that. Remember how I said we dissected monsters so we knew what things we could control and what the most important decisions were? Well, in the end, we can get the numbers to come out however we want. Mostly. Challenge is important because it tells us what numbers we need to target. And Traits are important because they can have a drastic impact on those numbers.

Check out DMG 280 – 281. That’s a big ole list of sample Traits you could slap on a monster. It’s tough to use because you have to actually go look up the monster to find out what the Trait does, but that’s 5th Edition for you. Notice how many of the Traits have an impact on the Challenge Rating. And notice that that impact is never “increase the Challenge by 3” or whatever. And that’s actually a good thing. It’d be much harder to build a monster if all the Traits f$&%ed directly with the Challenge.

Instead, each Trait changes some stat for purposes of calculating CR. So, for example, goblins have Nimble Escape. We’re told to figure their challenge as if their AC and attack were 4 points higher. That means, if I build a creature with Nimble Escape, well… what does that mean?

All else being equal, remember that every two points of AC increase Defensive Challenge by 1. So, if this ability is equivalent to increasing AC by 4, it’s a +2 Defensive Challenge. Likewise, every two points of attack increase the Offensive Challenge by 1. So, effectively, it’s a +2 Offensive Challenge. Now, if I design a creature and I want it to be a Challenge 2 creature. And I give it Nimble Escape, overall, that’s going to make it a Challenge 4 creature. But if I already PLANNED for that, I can reduce the creature’s AC and attack bonus accordingly.

Basically, the idea is to figure out the cool Trait or Traits that you want the monster to have. And then, LEAVE ROOM for those Traits in the stats.

THAT’S why we look at Traits next. But this can also get more complicated. Let’s talk about a few specific issues with Traits.

How Many is Too Many

Remember, every Trait takes up brain space in the GM. It makes the creature more complicated to run. In addition, the longer and more complicated the Trait, the harder it is for the GM to run the creature unless they’ve read the creature’s stat block beforehand. Now, you know you and you know what you can handle. And when you create a monster, you’re familiar with that monster. But if you ever share your monster, suddenly, the mental load that monster puts on the GM is a concern.

Now, I’ve written some LONG Traits here on this very website. They were necessary to make Paragon and Minion monsters work. But, in general, I don’t like doing that. A lot of custom monster creators focus on the Wall O’ Trait: giant, overly complicated Traits because that’s where all the flavor lives. And I advise strongly against that.

Likewise, I advise strongly against giving a creature more than two or three Traits. Occasionally, a creature warrants it. But if you have more than three Traits, you want those Traits to be simple and familiar. For example, Spider Climb is part of most GMs vocabulary and after a quick glance, it’s easy to remember. It doesn’t take up much brain room. Shark Telepathy (Sahuagin, MM 263) is not a part of most GM’s vocabulary, but the name says it all.

The more Traits you have, the simpler they should be. And even complicated Traits, shouldn’t be more than about ten lines of text unless they absolutely have to be.

Honestly, you can make some very interesting creatures just by mixing the Traits of different monsters together.

Racial Traits and Member Traits

As you can tell, I’m a big fan of the approach of having multiple stat blocks for the same species, varying them by tactics and equipment. And that’s where racial Traits come in. For example, every goblin I build will have the Nimble Escape Trait. That ties all the goblins together. And also, it means the players can learn something about goblins that they can rely on. No matter what variation of goblin I invent, the players will always at least assume they get a bonus action to Disengage or Hide. And that’s what you want. Yes. YOU WANT YOUR PLAYERS TO FIGURE OUT HOW YOUR CREATURES WORK AND RESPOND ACCORDINGLY. It creates consistency and it creates challenge by empowerment.

So, when I make a new race, I tend to start by figuring out the Trait (or Traits) that emphasize that represent inborn racial abilities. And then, I usually add a Trait that speaks to what that specific member of the race does a little differently. Remember that I said that. We’ll come back to it.

Now, here’s where things can get a little complicated. See? Traits affect the Challenge Rating of the monster, right? But that assumes the monster will actually get some advantage from those Traits. For example, Bugbears (MM 33) have two racial Traits, Brute and Surprise Attack. How do I know those are racial Traits? Because both Bugbears on MM 33 have them. But what if I made a Bugbear spellcaster or a Bugbear archer. That Brute ability adds extra damage to melee attacks. The spellcaster and the archer won’t really enjoy any benefit from those.

In those cases, I like to invent a similar Trait that keeps the same flavor. Bugbears hit hard, right? So maybe my archer isn’t an archer at all. He’s a javelineer. So he gets a version of Brute that allows him to add extra damage on thrown weapons. He’s still using his Strength. And the Spellcaster? Maybe he can add his Charisma to the damage roll with evocation spells to reflect that he’s unleashing furious extra energy based on the sheer force of his will (assuming Charisma is his spellcasting stat). In those cases, I’m replacing a racial Trait with a similar one that will be useful for the specific creature. And I’ll probably call them Brutal Throw and Brutal Warcaster or something.

That way, the players can still get to know that bugbears crank out brutal damage because of all the brutal they are. See?

So, for example, my Lemurians are modeled on lemurs and spider monkeys and jumpy, scurrying monkey creatures, right? I kind of like the idea of them scrabbling around the party, climbing on walls and on the ceiling, maybe dropping from above. And I like jumpy monsters. So, let’s figure out racial Traits for them.

Bullywugs have this neat Standing Leap. It just gives them the ability to jump really far. It’s not super useful by itself, but in the right terrain it could be fun. I’m just going to swipe that.

Also, I like the idea of the Lemurians scrabbling around on the ceilings, swinging overhead on the vine covered ceilings of the temple. Ettercaps and Spiders have Spider Climb. Done and done.

Now, those are both pretty minor abilities. And checking DMG 280-281, we find that neither of them have any actual impact on the creature’s challenge. Fine and dandy. So I can actually afford to add a third Trait, right? If the Lemurians spend their time swinging from vines and climbing on ceilings, they must fall occasionally, right? And falling carries two problems. First, you take 1d6 of damage per 10 feet that you fall. And second, if you take damage from fall, you end up Prone.

So what if we invent a Trait that covers Lemurians when they fall. Or when they drop. Say, when they drop from above to attack a PC. Let’s say that they ignore the first 20 feet of a fall. And even if they do fall and take damage, they still scurry away. They always land on their feet as it were.

Cat-Like Acrobatics. Lemurians do not suffer damage from falls of 20 feet. If a Lemurian falls more than 20 feet, it suffers damage for the fall as normal, but it does not land prone.

So, racially speaking, all Lemurians have these Traits:

Cat-Like Acrobatics. Lemurians do not suffer damage from falls of 20 feet. If a Lemurian falls more than 20 feet, it suffers damage for the fall as normal, but it does not land prone.
Standing Leap. The lemurian’s long jump is up to 20 feet and its high jump is up to 10 feet, with or without a running start.
Spider Climb. The lemurian can climb difficult surfaces, including upside down on ceilings. Without needing to make an ability check.

Which is actually a pretty fun combination of Traits. In a normal room, a lemurian can leap up to the ceiling, scurry along the ceiling, and then drop from the ceiling. It doesn’t need any checks to do that and it won’t take damage from the falls. That’s pretty damned flavorful.

But hold on. We have two varieties of Lemurians. Actually, we’re going to have four. But right now, we’re just building two. The Lemurian Darter and the Lemurian Behemoth. Now, I realize the Behemoth is a giant gorilla and the Lemurian Darter is just a humanoid monster like a monkey-kobold, but I still want to keep them tied to the same race.

Once I have one or more definitive Racial Traits, I take each specific member of that race, each separate stat block, and I try to give it one special Trait that says something about how that particular creature works. Obviously, if you’re just building a unique creature, you don’t have to worry about this. You just build the Traits in.

So, we’re building two varieties of Lemurians right now. First the Darter. The Darter is a skirmisher type. I like the idea of them bouncing around the battlefield like Yoda on speed, jumping into melee and then out again, or jumping up to the ceiling and then dropping from the ceiling and then running away. That would definitely feel very much like being mobbed by tiny monkey monsters.

So, how can we make the Darter dart? Well, goblins are pretty nimble and they tend to act like that. But they also rely heavily on stealth. The Lemurians don’t. They just like to stay out of reach. What if I give them a lesser version of Nimble Escape. What if they can Dash or Disengage as a bonus action. They can always take a second move or get out of a creature’s reach.

Scurry. The darter can take the Dash or Disengage action as a bonus action on each of its turns.

Voila. And what about the big guy? Well, the big gorilla guy is a big gorilla guy. He doesn’t jump around, darting into and out of fights, he jumps INTO fights and flattens whatever he lands on. Basically, he Pounces. Check out the allosaurus (MM 79) or the tiger (MM 339).

Pounce. If the behemoth moves at least 20 feet straight toward a creature and then hits with a XXX attack on the same turn, that target must succeed on a DC XX Strength Saving Throw or be knocked prone. If the target is prone, the behemoth can make one XXX attack against it as a bonus action.

That’s pretty cool. Especially because 20 feet is the exact distance by which it can fall from the ceiling onto an enemy. Or the distance by which it can make a long jump without a check. What’s with all the X’s? Well, those are all the things we don’t know yet.

Notice also I use a trick to separate Racial Traits from Member Traits. Because I name my creatures with compound names ala 4th Edition, I use the name of the race in Racial Traits and the title of the member in the Member Traits. You don’t have to do that. But it makes it easier to design several creatures at once.

So, just to review, the Lemurian Darter has these traits.

Cat-Like Acrobatics. Lemurians do not suffer damage from falls of 20 feet. If a Lemurian falls more than 20 feet, it suffers damage for the fall as normal, but it does not land prone.
Scurry. The darter can take the Dash or Disengage action as a bonus action on each of its turns.
Standing Leap. The lemurian’s long jump is up to 20 feet and its high jump is up to 10 feet, with or without a running start.
Spider Climb. The lemurian can climb difficult surfaces, including upside down on ceilings. Without needing to make an ability check.

And the Lemurian Behemoth has these traits.

Cat-Like Acrobatics. Lemurians do not suffer damage from falls of 20 feet. If a Lemurian falls more than 20 feet, it suffers damage for the fall as normal, but it does not land prone.
Pounce. If the behemoth moves at least 20 feet straight toward a creature and then hits with a XXX attack on the same turn, that target must succeed on a DC XX Strength Saving Throw or be knocked prone. If the target is prone, the behemoth can make one XXX attack against it as a bonus action.
Standing Leap. The lemurian’s long jump is up to 20 feet and its high jump is up to 10 feet, with or without a running start.
Spider Climb. The lemurian can climb difficult surfaces, including upside down on ceilings. Without needing to make an ability check.

How Traits Affect Challenge

Now, the whole reason we sit here figuring out the traits is so that we know what adjustments we have to make to the monster stats to allow for them without f$&%ing up our chosen Challenge Rating. What you want to do is make a note on your note paper (or computer) about what affects the traits have on the creature.

For example, let’s run through these.

First, Pounce. It’s the easiest. DMG 281 says to just assume the creature’s damage output increases by the bonus attack that it gains once out of every three rounds. So, if the creature has an attack that does 10 damage, and when it knocks a creature down with pounce, it gets a bonus attack of the same time, over the course of three rounds, it will do 40 damage. Right? Divide 40 by 3, and we get an effective damage output of 13 per round. We just want to remember that we’re going to have to factor this in.

Second, Spider Climb and Standing Leap are both on DMG 281 also. And neither of them has an impact on Challenge Rating.

And now we’re stuck on two more. Cat-Like Acrobatics and Scurry. How the hell do you figure out how brand new abilities affect the Challenge of a monster. Well, you use your f$&%ing brain. And you try to parse down the ability to something similar.

So, we might be tempted to think of Scurry as similar Nimble Escape. But if you look carefully at Nimble Escape, you’ll realize that most of the effect Nimble Escape has is because of the free Hide action. That +4 to Attack and AC is the joint impact of being an unseen defender and being an unseen attacker. After all +4 and -4 are just secret code words for “assume the thing has Advantage or Disadvantage.” We’ve taken the Hide out, so we’ve taken the biggest impact.

What IS the effect of giving a creature a bonus Dash OR a bonus Disengage? Well, here’s where you have to study things a little. Orcs are Aggressive (MM 246) which allows them to move their speed as a bonus action toward a hostile creature. It lets the creature cover ground more quickly and stay engaged with a foe. And it’s basically just Dash as a bonus action. Bingo. So, half of Scurry (the Dash) is worth the same as Aggressive. And DMG 280 says that’s basically a +2 damage output per round. Why? Because where other creatures might lose one round of damage when they are closing to engage, these creature doesn’t.

What about the other half of Scurry? The bonus Disengage. Basically, as a bonus action, the creature can decide not to provoke opportunity attacks for moving out of range. Well, that sounds an awful lot like what Flyby does for a Peryton (MM 251). And Flyby has no impact on Challenge.

So, Scurry is essentially worth 2 extra points of damage per round.

And we could stop there, right?


Remember how I said there’s a lot of finesse and a lot of thinking about things just the right way? Look, if you stop there and say the Lemurian Darter has two extra points of damage output every round and that’s the sum total of the effect of all of its traits, you probably won’t break anything. But you’d be wrong.

And your clue might be in Flyby.

Why doesn’t Flyby have an impact on Challenge? Seems like it should, right? Well, the reason it (probably) doesn’t is because, in order to have Flyby, you have to be able to fly. And flying DOES have an impact on challenge. Specifically, a creature below CR 10 that can fly and can deal damage at range effectively has a larger Armor Class because it can stay out of reach. You treat it as if its AC is 2 points higher. Right?

The reason that doesn’t affect melee creatures is that the melee creature has to close to attack. And at that point, a smart party will ready their melee attacks to beat the creature up when it closes. And Flyby doesn’t really screw with that strategy at all. In fact, from the way Fly and Flyby are handled, we can infer that the system doesn’t consider Opportunity Attacks to be a normal occurrence. If it did, then any ability to avoid Opportunity Attacks (like Flyby) would have an impact on challenge. Instead, D&D assumes most creatures will avoid Opportunity Attacks most of the time and therefore doesn’t factor them into PC damage output. That’s good to know. A free Disengage doesn’t change the Challenge numbers.

But we already knew that. So why am I saying we stopped too soon. Well, this is kind of complicated, but in the end, effectively, we’ve actually made a flying creature. We’ve built these monkey things that can leap to the ceiling, fall from the ceiling, dart up walls, and freely disengage and run around. As long as they are melee creatures, that’s no big deal. They have to close to do anything and that means the Ready action will allow melee combatants to stay in the fight.

But what if we also built a Lemurian that primarily survived by throwing weapons or shooting arrows. Some sort of Lemurian Pelter? Well, suddenly, the combination of all of those racial traits does have more of an impact. It’s essentially a flying creature with a ranged attack.

And that’s what separates a good monster designer from a great one. The ability to think beyond the traits and realize sometimes things are more than the sum of their parts.

Sure, my Lemurian Darters just need slightly lower damage every round to compensate for the bonus Dash I’ve attached to Scurry. And my Lemurian Behemoth just needs to be treated as if it has one extra attack every three rounds, which I can figure as if all of its damage is increased by 33%. If its attacks deal 10 damage, I need to treat them as 13 to account for the extra 10 damage every third round.

But when I go ahead and make that Lemurian Pelter, I need to act like its AC is 2 points higher because I’ve actually made a flying ranged creature. Effectively.

Other Things

Now, remember there’s a handful of other things that do also affect the challenge of a monster. Damage Resistance and Immunities, Flight (which we already discussed), and Saving Throw Proficiencies. You want to also make those decisions now. The key is to figure out everything that affects the Challenge of the monster. I’m not going to add anything else here, because those effects are all much simpler than traits. I’m happy with my Lemurians.


The last thing I need to discuss about picking Traits (and don’t worry, this is the hardest f$&%ing part), is Spellcasting. Holy f$&% does Spellcasting complicate everything.

See, Spellcasting a is gigantic pile of extra traits and actions and stats. Give a creature scorching ray, well, you’ve given it three attacks in one round that each deal 7 (2d6) damage. And if it has two slots to cast cast scorching ray with, well, that’s two rounds of 21 damage output. A creature with mage armor effectively has a different AC for the entire combat. A creature with expeditious retreat is basically Aggresive like an orc. At least, it is if it’s a melee creature. Otherwise it isn’t.

And frankly, to do it right, you have to think through each spell and what impact each spell is going to have and whether it’s worth adjusting the Challenge for. Obviously, two slots of scorching ray are definitely changing that Offensive Challenge Rating. But expeditious retreat probably isn’t unless the spellcaster is a melee creature to begin with.

But honestly, you can usually fake it by looking at the most damaging and most defensive spells in the arsenal and assuming the creature cranks those out. Because those tend to have the biggest effect. I’m not saying a spell like Grease or Blindness/Deafness aren’t effective in the right circumstances. But, what I’m saying is, if the creature uses its second level slot for Blindness/Deafness that’s not going to have any more or less impact than Scorching Ray. In theory, spells of the same level are balanced against each other.

Spellcasting takes a lot to balance and, honestly, it’s almost impossible to get it perfect. You just have to focus on the biggest effects and assume all of the other spells basically fall in line.

I tend to avoid spellcasting monsters because they are such a pain in the a$& to get right. Still, I did just pit my players against a pretty cool Hell Goblin warlock.

Step 3: Picking Your Numbers and Their Dependencies

Let’s review where we are at right now.

Lemurian Darter
Small Creature
Challenge 1/2 (Def 1/2, Off 1/2, Prof +2)
Cat-Like Acrobatics. Lemurians do not suffer damage from falls of 20 feet. If a Lemurian falls more than 20 feet, it suffers damage for the fall as normal, but it does not land prone.
Scurry. The darter can take the Dash or Disengage action as a bonus action on each of its turns.
Standing Leap. The lemurian’s long jump is up to 20 feet and its high jump is up to 10 feet, with or without a running start.
Spider Climb. The lemurian can climb difficult surfaces, including upside down on ceilings. Without needing to make an ability check.
Effectively +2 damage per round

Lemurian Behemoth
Large Creature
Challenge 4 (Def 3, Off 5, Prof +2)
Cat-Like Acrobatics. Lemurians do not suffer damage from falls of 20 feet. If a Lemurian falls more than 20 feet, it suffers damage for the fall as normal, but it does not land prone.
Pounce. If the behemoth moves at least 20 feet straight toward a creature and then hits with a XXX attack on the same turn, that target must succeed on a DC XX Strength Saving Throw or be knocked prone. If the target is prone, the behemoth can make one XXX attack against it as a bonus action.
Standing Leap. The lemurian’s long jump is up to 20 feet and its high jump is up to 10 feet, with or without a running start.
Spider Climb. The lemurian can climb difficult surfaces, including upside down on ceilings. Without needing to make an ability check.
Effectively one extra attack worth of damage every three rounds

Now, I can start working out my numbers. And as I’m doing that, I’m looking for dependencies. What do I mean?

For example, if the creature needs an attack modifier of +4 and I know it’s Proficiency bonus is +2, that tells me that its Strength modifier must be +2. Which also tells me it’s damage will be SOMETHING +2. Remember, this is all about setting the most important things and letting the rest of the stuff fall into place.

There’s five numbers that determine challenge. Hit Points determine Defensive Challenge, which is then modified by AC. Damage determines Offensive Challenge, which is then modified by Attack and Save DC.

Let’s start with the Lemurian Darter. He’s pretty simple. I’ve already decide he’s a balanced monster. He doesn’t favor attack or defense. We can pretty much set his numbers at the baseline for a creature of his Challenge and be done with.

Let’s start with Defensive Challenge. A Challenge 1/2 creature has 50-70 hit points and an AC of 13. But those hit points actually seem a little high. And this is where we are going to employ a math trick again.

Remember, for every two points by which the AC varies, the Defensive Challenge has to be adjusted by one row on the table on DMG 274. If I want to reduce the Hit Points (because that seems high for a small monkey creature), I can simple increase the AC. For example, if I target 36-49 Hit Points, that’s a Challenge of 1/4. But the AC should only be 13 in that case. If the AC is 15, that bumps up the Defensive Challenge to 1/2.

But that still seems high for a humanoid creature, right? HP 36-49? I mean, I could keep pumping the AC up, but that gets ridiculous fast. What can I do? Well, I can add another trait that has an effect on the Defensive Challenge. Or, I can just decide that maybe Defense 1/2, Offense 1/2 isn’t a good target at all. Maybe, Defense 1/4, Offense 1 might be better.

Then, to hit Defense 1/4, I can start with 7-35 HP and have an AC of 15. Look carefully at the table and see how I’ve come up with all of that.

And this is why I spent SO MUCH TIME explaining Challenge. Because if you understand the pushes and pulls, you can make these tweaks as you design.

So, 7-35 HP. These things are basically monkey goblins, so I don’t want them to have huge amounts of HP. Goblins start at 7 (2d6). That seems a little low considering this is a 4th level adventure. Let’s say 14 (4d6). And they don’t need any Constitution modifier. They aren’t that tough. Which, by the way, tells me my Constitution score is going to be 10 or 11.

What about AC? Well, I need an AC of 15. How can I get there? Do these things wear armor? No. They rely on agility and natural tough skin and fur. So, I can just say AC 15 (natural armor) and be done, right? Well, sort of. It’s actually kind of weird for monkey skin and fur to be worth AC 15. So a big component of that, is probably Dexterity. I want them to have a Dexterity modifier of at least +3, so the monkey skin and fur aren’t worth more than 12 + Dexterity Modifier.

But the Dexterity modifier isn’t just going to be determine Armor Class, is it? Because these things aren’t very strong. They are small monkey creatures. They use Finesse weapons. Which means their attack and damage are dependant on Dexterity.

Well, offensively, the creature is going to need an Offense Challenge of 1. Which means it’s going to do 9-14 damage with a +3 attack bonus. And already, we see a problem. We know it’s Proficiency bonus is going to be +2. Which means its Dexterity must be +1. That ain’t good. I mean, we could make the creature’s attack based on Strength. But that’d be weird. What do we do?

Well, if we make the Dexterity +3, that means the attack bonus is +5. Two points too high. And just like we did when we traded off AC for HP, we can trade off Attack for Damage. In this case, we bump the damage down one row on the table. Now, the damage has to be 6-8.

But remember, two points of that damage comes from the fact that the creature gets a bonus move, right? Those traits. Yeah. So, the creature’s damage has to be 4-6. AND we know the creature has +3 damage. Why? Because creatures use the same Ability for damage as they do for attacking. So, we need a die plus 3. Well, 1d6 averages 3.5 which we round down to 3. So, the creature could do 1d6+3 damage and have a +5 to attack. It’s accurate, but it doesn’t hit tremendously hard.

So, our Lemurian Darter now has the following stats.

Armor Class 15 (natural armor)
Hit Points 14 (4d6)
Dex 16 (+3), Con 10 (+0)
Cat-Like Acrobatics. Lemurians do not suffer damage from falls of 20 feet. If a Lemurian falls more than 20 feet, it suffers damage for the fall as normal, but it does not land prone.
Scurry. The darter can take the Dash or Disengage action as a bonus action on each of its turns.
Standing Leap. The lemurian’s long jump is up to 20 feet and its high jump is up to 10 feet, with or without a running start.
Spider Climb. The lemurian can climb difficult surfaces, including upside down on ceilings. Without needing to make an ability check.
Attack. +5 to hit, 6 (1d6+3) damage

What about our Behemoth?

Let’s start with his Offense. Because we’re going to run into trouble there. Trust me.

We want him to have an Offensive Challenge of 5. Which means 33-38 points of damage every round with an attack of +6. That’s a lot of damage. Of course, we have to factor in the idea that that damage is actually not all real. Remember, we have to add one third on to it’s damage to account for a bonus attack.

Normally, what we would do for a creature like this is to use Multiattack so that we don’t just have a ridiculous attack that does 11d6 damage. But Multiattack is a problem here. Why? If the creature is allowed to make two, say, Slam attacks, do they both trigger a Pounce if the creature moved first? By a strict reading of the rules, they do. And that actually makes things funky. Notice the creatures that have Pounce don’t have Multiattack. And the designers were SUPER CAREFUL about this potential weird interaction. Proof? Check out the Goristro (MM 59) whose Charge is similar to the Pounce. Notice that if he uses his Multiattack, he can’t trigger Charge. Because Charge is based on the Gore attack. And he can’t use Gore as part of a multiattack.

This actually suggests a neat solution.

What if the Lemurian Behemoth has a slam attack, a simple punch attack. And it can crank out two of those per round. Or, it can do a powerful two-legged kick by using its arms to launch itself at its foe. And THAT attack is what it Pounces with, essentially launching itself like a gorilla ballistic missile. And if it manages to down a foe with the kick, it bites the foe’s face.

How do we work out how to break down the components of the damage? Well, remember, we need to average the damage over three rounds and assume the bonus attack combo only happens once. That makes sense. The creature will probably lunge at someone, Pounce, Bite their face, and then spend the next two ranges engaged with the target and beating it up. Now, over three rounds, we need to crank out 99 to 114 points of damage (33 to 38 times 3 rounds). There’s a couple of ways we can do that. But the easiest way is to just split up the 100 damage between three rounds, remember that two of the rounds have to be the same. For example, we could do 33/33/33. That’s the easiest. But boring. Or we could 40/30/30. Or even 50/25/25.

Now, we always want to worry about TOO MUCH variation. Big spikes kill PCs. And they throw everything off. But we do want SOME variation. So I like the 40/30/30 split. But now we have to split it further.

30 means the two punches will do 15 damage each. But we can split 40 a variety of ways too. It seems to me like the kick should do the most damage of anything. The punches should be next. And the bite is probably the weakest. This is a gorilla, after all. Not a shark. The bite is insult to injury. I knocked you the hell down, now I’m going to eat your face. We could easily do 20 and 20. But I’m inclined to front load the damage because, remember, the creature has to get past a Strength saving throw to get that second attack and it still has to hit. Right? Remember, it only gets the bonus attack if the target falls prone. Of course, if the target falls prone, the bonus attack has Advantage. But even so. Let’s split it 30/10. The kick is as powerful as two fists. And the bonus damage is weaker than a fist.

So we need damages of 15, 30, and 10. Complicating this is that the static bonus has to be the same on all of them. We’re always going to be adding Strength. Now, ideally, that Strength modifier will be… what? Well, we want an Attack Bonus of +6, right? DMG 274 tells us so. But the creature’s final Challenge is only 4. So it’s proficiency bonus is +2. That means it’s Strength gives it a +4.

So, we need dice codes to generate 11, 26, and 6. Or close enough. We’re at the low end of the range here. 2d6 is 7, right? So that’s our Bite. How do we hit 11? 2d10 averages 11. Perfect. So the fists are 2d10. 28 is a little trickier to hit. 4d12 would give us 26. And those dice codes are absolutely perfect. And I’ll explain why, if you’ll indulge me. And you’d better. Because I’m f$&%ing brilliant.

Now, this is a weird, complicated little point, so feel free to ignore it. But people watch the dice you roll and it signals things. For example, the size of the dice you are rolling says something about how dangerous the attack is overall. The fists are d10s, the bite is d6, and the kick is d12. And that matches our idea about how relatively powerful the attacks are.

Now, the number of dice rolled also conveys something about the power of the attack. Both the fists and the bite involve two dice. Those are normal attacks for the creature. That’s just where its baseline is. But the kick is TWICE as powerful. The kick is its nova. Or, in this case, it’s starting gambit. No one wants to be kicked by the thing.

Also, it’s important to keep the kick damage below the total of two fists. Otherwise, there’s never a reason not to kick. Two fists deals slightly more damage even though there are two attack rolls involved. But they also let the creature pound on two different targets. It has some versatility.

Anyway, so that’s offense. What about defense.

Defensively, this thing only has a Challenge of 3. Which means the baseline is 101-115 hit points and an AC of 13. Now, I want this thing to be easy to hit, but soak up damage. If I can reduce its AC by 2, I can move to the next higher HP bracket, 116-130. I want the PCs to notice that this thing is a really easy target that takes a real beating. So, maybe that’s what I do.

And here’s where my obsessiveness shows. In theory, there is nothing that says you can’t just say Armor Class 11 (natural armor) and make its Dexterity modifier anything you want. After all, we know it’s using Strength for its attacks. And you can do that. You totally can.

BUT, I don’t like that solution. And here’s why. Because in my universe, I have established that Lemurian Hide is Light Natural Armor that grants AC 12 + Dexterity modifier. And this Lemurian is bigger and tougher. He could have the SAME hide, but he shouldn’t have a WEAKER hide. Again, this is JUST my brain. You don’t have to go this far. I do. And that is why I know, that the giant Lemurian is powerful, but not agile. His Dexterity modifier must be -1.

Meanwhile, HP. We want to target the high end of the bracket, the 130. And we know that large creatures roll d10s for hit points. We want the creature to have a good Constitution, but Strength is probably it’s schtick. So, the Strength is +3. Constitution should be +2. So, how many times do we have to roll 1d10+2 to get up to 130? You know how to do this already.

So, what do we know about our Lemurian Behemoth?

Armor Class 11 (natural armor)
Hit Points 127 (17d10+34)
Str 19 (+4), Dex 9 (-1), Con 15 (+2)
Cat-Like Acrobatics. Lemurians do not suffer damage from falls of 20 feet. If a Lemurian falls more than 20 feet, it suffers damage for the fall as normal, but it does not land prone.
Pounce. If the behemoth moves at least 20 feet straight toward a creature, including straight down from above, and then hits with a Kick attack on the same turn, that target must succeed on a DC 14 Strength Saving Throw or be knocked prone. If the target is prone, the behemoth can make one Bite attack against it as a bonus action.
Standing Leap. The lemurian’s long jump is up to 20 feet and its high jump is up to 10 feet, with or without a running start.
Spider Climb. The lemurian can climb difficult surfaces, including upside down on ceilings. Without needing to make an ability check.
Multiattack. Two slam attacks
Slam. +6 to hit, 15 (2d10+4) damage
Kick. +6 to hit, 30 (4d12+4) damage
Bite. +6 to hit, 11 (2d6+4) damage

Now, I assume I don’t have to explain how the Saving Throw DC was calculated for Pounce. But also note that I slightly reworded pounce to call attention to the fact that the creature could drop from the ceiling. Even though it doesn’t NEED to be specified, it’s such a signature tactic that I don’t want to risk some GM missing the possibility. Right?

Step 4: Finish the Damn Monster

Okay, here’s the secret. You’re actually done now. You’ve figure out everything that affects the Challenge of the monster. As long you don’t go tweaking one of the things that actually screws with the difficulty (like suddenly deciding your monster is flying and immune to mundane weapons), nothing else you put in the stat block matters. It’s all up to your sense of flavor and fluff.

Me? I like to leaf through the Monster Manual and find creatures that are similar to see what sort of extraneous statistics I can set. And I tend to just go down the stat block and fill in everything that isn’t already set by the previous steps.

For example, I’m trying to figure out how Intelligent I want to make my Lemurians. They are social creatures and they use tools (because they have pelters that throw things), but they aren’t tremendously intelligent. They remind of ettercaps but they could be as dumb as ogres. I think the big guy is a bit dumber. But they are clever. They are survivalists. And they are alert. So, they have a decent Wisdom score. A slightly low Charisma, and an Intelligence around 5. I don’t see them as having any extraordinary senses though. Just my choice. They are diurnal or crepuscular. So, it’s pretty easy for me to just bang out some stat blocks.

Lemurian Darter



Not As Complicated as It Seems

Those lemurians are actually complicated little critters. And I did that on purpose.If you can follow everything I did, you can build great monsters. Simple ones and complicated ones. It’s not a difficult process and you can fly it through pretty quickly once you get it down. Honestly, the longest part of making monsters now is (a) coming up with cool traits that bring your monsters to life and (b) typing out the goddamned stat blocks.

But let’s talk about something else too. Remember how I said I wanted my little tribal lemurians to have friends? Let’s talk (briefly) about that.

How to Make Friends for Your Monsters

Whenever I decide to make a “race” of creatures that I know are going to have a couple of different, similar, varieties. I start with what I’ve nicknamed “the skirmsher.” That was the 4E term for what was pretty much the most generic version of any group of monsters. Yeah, I know, it had a different definition. But that’s how it worked out.

Notice I purposely kept the Lemurian Darter generic. I tried to keep its offense and defense in line (as best as I could, I did have to reduce it’s HP). And I also specifically noted the one trait that was it’s “tactical” trait. Why? Now, I can build variations on that template.

I’m not going to go through the entire process. But I’ll show you the shortcuts.

First, copy and paste the stat block. You’re just going to fiddle with some things to change them.

We need a tactical trait for each of our variations to replace the Scurry ability. As I mentioned, I have the Pelter. His job is to be a ranged combatant. And I have the Protector. His job is to be the defensive one. I still want to emphasize speed and mobility and acrobatics. So the new traits should reflect that. And the best source for “tactical” traits – that is traits that give a creature a specific tactical bent – is the NPC section of the Monster Manual (MM 342 – 350).

For the Pelter, I could go the simple route of giving them multiattack because rapid shot is kind of a signature for an archer. But then I see Assassinate on the Assassin and Sneak Attack. I kind of like the idea that the Pelters are smaller and more cunning. And they are good at dropping rocks (or throwing them) right on the heads of surprised people who walk under their trees. That would work well. Right? But only if the creature can be stealthy. I just don’t want to call it assassinate. Because that’s not what it is.

What’s the effect of those two abilities? Well, that’s tricky. It’s not in the DMG. But we can work it out. The creature is probably going to have it’s Sneak Attack every round, right? After all, we expect that it’s rarely alone, so it will always have an ally in melee. That means we just assume it will always do the extra sneak attack damage and increase the damage output accordingly.

What about the assassinate power. What effect does that have? Well, if we look at the Doppelganger, it has ALMOST the Assassinate Trait divided between its two Traits: Ambusher and Surprise Attack. Ambusher represents a momentary, one round advantage on an attack roll. It’s a little more situational than ours, but close enough. And Surprise Attack tells us how the DMG suggests we figure a damage boost in the first round based on surprise.

Now, that means that the creature has an effective +1 Attack, which is fine because +1 Attack isn’t enough to change the Offensive Challenge. But what is it’s damage? Well, each round it will roll a damage die plus sneak attack plus damage modifier. And in the first round, we’re going to assume it crits. Which means it rolls double damage. Which means, effectively, its damage across three rounds is increased by 33%, just like the Behemoth. And that could be a lot of damage.

And this is where things get kind of complicated. Which is why I decided to add this section in even though it’s added a good hour onto all this typing. You guys just don’t appreciate me enough.

You have to decide, when making a variant creature, whether you want to keep the Challenge the same or not. And whether that is even possible.

In this case, I want to keep the Challenge the same. Why? Because I want to build monkey teams of 3 to 6 little monkey monsters at a time. There’s a lot of variety I can build with three variations of mix-and-match-monkey-monsters. I can build at least five interesting combats with just those three creatures in different combos.

So, the pelter, defensively is actually a little bit stronger. Remember when we realized that our combination of monkey traits makes this effectively a ranged creature with flying? We need to figure the Challenge as if it’s AC is 2 higher. Which means, it’s Defensive challenge, without changing any other stats, is 1/2 instead of 1/4. I need to keep the total Challenge at 1/2 , right? And I could probably call it close enough if I keep the Offensive Challenge at exactly 1. Any higher than that and I really have to figure the Challenge as if it’s higher.

On top of that, my hands are kind of tied with the Dexterity. See, I can’t have the little sneaky monkey sharpshooter have a lower Dexterity modifier than the standard monkey. That’s absurd. So I can’t touch the AC. I’m stuck with it. And the HP are already as low as they can go. And the Attack Bonus is based on the Dexterity. I can’t move that. That means the monkey can ONLY DO 6-8 damage per round over three rounds. Is that possible?

Well, if I assume 1d4 for a thrown rock +3 Dexterity modifier +1d6 sneak attack, the damage is 8. Perfect. Except for the damned first round critical hit. Remember, that means in the first round, it’ll do an extra 2.5 + 3.5 damage or 6 damage. Divide that over three rounds, and that’s 2 extra damage a round and we’re up to 10 damage per round. And the Offensive Challenge gets bumped.

So, we have a difficult choice. Do we bump the pelter to Challenge 1 or do we drop the critical hit effect on the first round? Without that extra damage, we’re golden. And it’s up to you. Me? I’m dropping the crit effect.

Lemurian Pelter

What about the protector? Amusing as it sounds, I like the idea of a little monkey with a plank shield. That’s why I made them smart enough to use tools. That’ll give it a +2 to AC. Which puts it in the same boat as the Pelter. We need to make sure the damage stays low. But what about a neat trait?

I kind of want it to be able to interpose its shield as a reaction, to protect its monkey buddies. But I also want to make them more like monkey leaders. And for that, I’m kind of looking at the hobgoblin warlord. Hobgoblins have Parry, they can grant themselves a bonus to AC as a reaction. Logically, if you have two creatures of the same Challenge, does it matter which one gets an AC bonus? The AC bonus will be substantially the same regardless of which creature gets it. So, I say that Shield Interposition to protect an adjacent ally is AT BEST equivalent to Parry. And frankly, that’s probably overestimating anyway. After all, it’s more situational to be forced to use it on an adjacent ally. In the end, the effect is a +1 increase to AC for Defensive Challenge anyway. And that doesn’t bump the effect enough.

But as I look at the hobgoblin, I notice that Leadership thing. And I like it. So, I’m going to give my little Lemurian Protector Leadership and the ability to grant disadvantage on an attack against an adjacent ally (+4 to AC). As long as I also keep his damage down, his Challenge isn’t affected. I kind of want to assume he punches with his shield. That requires me to make him a little stronger because that’s a Strength attack in my mind. But how strong can I really make the guy? Maybe 13 tops. He’s a little monkey!

Now, where am I? Well, he has +3 attack and does 4 (1d6+1) damage. That drops his Offensive Challenge to 1/4 . Where’s his Defensive Challenge? Well, his AC is 17 and his HP are 14. That makes his Defensive Challenge 1/2. I can justify calling that a Challenge 1/2. It’s halfway between 1/4 and 1/2. And that’s fine. But, if this guy is going to be a leader, maybe he could use some more HP. After all, he can have up to 35 HP before it changes any of the numbers. And with a little more HP, I’d feel more comfortable calling him a true CR 1/2.

Lemurian Protector

Now Go Make Your Own Monsters

As you can see, there IS a process to making monsters, but it’s more important to think the right way. To think in terms of the connections between Offensive and Defensive Challenge, between AC and Hit Points, between Attack and Saving Throw DC and Damage, and how Traits and other abilities affect the whole mess. That’s why I included that last part about fiddling with monsters you’d already made. Because once you see how everything is interconnected, it can be easier to tweak a monster than start from scratch.

You can download the lemurians here. They seem like fun monsters. A little complicated, but that’s because I wanted to show off a lot of concepts. Feel free to use them in your own game.

Extra Credit

Okay, here’s the story. It just so happened that a friend on Twitter was looking for some help building a custom monster. A spellcaster. So, I offered to have a Skype chat as long as I could share the transcript as a sort of object example of how to build a monster.

The transcript is linked here. And you get a bonus hobgoblin warcaster for your trouble.

31 thoughts on “Monster Building 202: The D&D Monster Monster Building Lab Practicum

      • Thanks for the mention! The ref=2.2.3 actually tells us that someone is upgrading from 2.3.3 (or whatever version they’re upgrading from) so I was surprised that there were SO MANY people upgrading this weekend!

        Something we have planned is translation support for other languages and SVG output! Glad you’re liking the software!

  1. I’m trying to build some monsters using Goblins as a starting point, but I can’t figure out how these calculation work for a regular Goblin. With an average 5 points of damage the base Offensive CR is 1/4, which gets bumped up to 1/2 due the Effective Attack Bonus being +6 from Nimble Escape. The Defensive CR is 1/8 based on 7 HP, and this gets bumped up to 1 because of the Effective AC being 19 (due to Nimble Escape again). Averaging these out I get a final CR of 1/2. Am I doing something wrong, or is this a case of the designers bumping the Goblin CR down for some other reason?

    • You are 100% entirely correct. The goblins in the Monster Manual do not conform to the Challenge calculation rules. And, if you look back at the goblin stats I’ve made on this site, mine break the rules the same way.

      I’ll tell you this: the goblins do not follow the rules. But they are not TECHNICALLY wrong. Can I use this comment as an Ask Angry. There’s an important point here. But it won’t fit in a comment section.

  2. Just before the not quite final behemoth statblock you talk about working out the HP and set the constitution modifier to +2, mentioning that you want it to be less than the strength modifier of +3, but earlier in the article you give the creature a +4 strength modifier. I’m guessing this is just a typo?

  3. Alright, I have been reading your articles Angry, and I will say, it changed my D&D outlook entirely. Unfortunately, as I have been new to D&D only 2 years ago, my first campaign I played, (which shaped my first DMing campaign initially) was ran by an egocentric twat who believed he is above the rules of D&D 3.5E. Initially, he started the game with horrifyingly stupid rules which were simply backed to make DMing for him “easier”(but not really); No strength to damage rolls with melee attacks or anything else, don’t cut the modifier in half after 12 EX: Dexterity 17 = +5 modifier, ect… Just a bunch of bogus that I began to loathe, and as the campaign continued, I began to mature as a D&D player, reading rule books and figuring out how blatantly robbed I was from a true good D&D experience. Here’s the most unfortunate part, I started my own campaign (3.5E) with one player prior to learning fully about what the game was supposed to be like. So the doubled modifier, the obserd critical hit ratios and so forth remained. I bandaged what I could with my campaign as best I could as I have been learning with the rule books, and (most recently) with your articles. (I allowed strength to damage rolls from the getgo, because it’s too obvious) I can’t wait till I bring the story to a close and start on a new 5E campaign where I can make it right from the start. Your articles have been truly enlightening, so thank you Angry. I wish I could take an article and show it to my first DM to describe how wrong he is, but the ego on this guy wouldn’t allow logic to root into his thick skull.

  4. O Mighty and Hallowed Angry

    The pounce states that the pouncer makes his second attack as a bonus action. Since one can only have one bonus action, there is no way you could make 2 bonus attacks from pounce with a multiattack. Isn’t that the whole point of action economy ?

    Am I missing something ?

    • The problem is that the creature would need to make two Strength saves to avoid being knocked prone by the Pounce. This would increase the chances of getting that bonus action attack, even though you are correct that you won’t get it twice as you only get one bonus action. It’s also weird to have two save effects right after each other.

  5. Hey Angry, the DMG does not mention how attacks or abilities that inflict conditions affect CR; rather it just says “Add some to make it more unique!”. Do you have any advice on how to calculate the effect condition infliction has on CR?

  6. All right I’ve got a teaser for you.

    Lets say you have a creature who can use a Breath weapon but instead of it doing damage it shoots out sand. The sand pushes people back 10ft (no save) and Dexterity DC 12 save to avoid being blinded until the end of the creatures next turn.

    So normally with a breath weapon you’d assume it hits 2 people and they both fail their save (as per dmg). You’d take the damage from the attack and include it in your 3 round average damage (? as far as I’m getting this whole process)

    However, we’re not dealing with damage anymore so how do we calculate this into the creatures dmg calculations? I’m interested in what people think here.

    Personally, the solution I came up with was +2 effective AB / +2 effective AC for CR calculations.

    If we look at nimble escape and its +4ab / +4ac modifier, and we accept angry’s reasoning, that hiding essentially grants advantage on Attack and Defence. Then, we can assume that since blindness also provides the same mechanical benefit it should be costed the same. Then why have we not given the ability a +4/+4 penalty? Well, the dmg already tells us to assume that only 2 people are affected by the breath weapon, whereas with hiding it appears to be assumed that the creature is hidden from all enemies. Given average party size of 4-5, it is reasonable to assume this blindness effect is only half as effective as being hidden.

    At least I think? I’m assuming the last bit about hiding. It seems consistent with other damage calculations assuming they always hit.

  7. Pingback: Making Monsters, based on what I have #DND #RPG (also a hat tip to @TheAngryGM) | FreeRangeGeek's Adventures

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  9. Great article. I know you’ve talked about how testing caused tweaks in CR, but I’m looking at a specific case that is raising some questions.

    Phase Spider. Challenge 3
    AC 13, HP 32, +4 to hit, 25 DPR, DC 11
    Unknown adjustment trait: Ethereal Jaunt (bonus action in or out of the ethereal plane)

    When I run the numbers on DMG 274, I get OCR 3, DCR 1/8. Now I could see potentially doubling HP to account for ethereal jaunt (though readied actions makes me hesitant). Thus, I’m just wondering how this spider ended up at CR 3 overall when I feel like CR 2 may even be a little generous. Is it the high damage output that can put PCs down too easily below level 3?

    Any insight would be great.

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  11. Thanks for posting this. I’ve used your advice to build one complete monster and 3 versions of another, both based on enemies from fiction. One is Gollum (CR 2), who I’m going to use for a campaign based on “The Hobbit”, and the other (with 3 different versions) is Ultron from the second Avengers movie.

    I’m including Ultron in my vague plans to run an Avengers campaign at some point. Figuring out how to get 3 different versions at different challenge levels (6 for the prototype, 2 for the minions, and 9 for the boss) was fun, and a lot easier with your guide to help me. I’ll have to see how they work in practice, but I’m reasonably sure I’ve got the maths right and they’ll work roughly as intended. The most useful thing was the reminder that Offensive and Defensive challenge can be different – that saved me when I was trying to figure out how to nerf the minions down to CR2 when I couldn’t mess with their attack capabilities too much. I just knocked their hit points down to about a quarter of what they had been.

    I’m currently working on a version of the Great Goblin, from “The Hobbit”. I’m building him at CR 5, with the idea that the PCs will encounter him as a boss fight around level 3 or 4. My problem is that he’s not a goblin! That’s why I can’t just use a normal goblin stat block, or even base something on them. He’s nothing like normal goblins – for one thing, he’s a whole 2 size categories too big! So I feel justified in not giving him Nimble Escape as a racial ability, because it really doesn’t make sense for a creature with that bulk. On the other hand, I don’t know what to give him instead, or how to account for the fact that he’s massively fat.

    Speaking of which, any ideas on what the damage should be when a Large creature falls over onto someone? I want to have that as part of a Reaction called “Death Throes” – everyone in 5 feet makes a Dex save to avoid being squished beneath his corpse, which seems like a really fun idea. I can’t find any rules for what damage it should do, though, and all the things that sort of fit, like Improvised Weapon or Falling damage, seem way too low.

      • Thanks! I hadn’t discovered Mephits before, and they look quite cool. I’ll have to run the numbers on them to figure out what Death Burst does to their CR, which should help with the Great Goblin. ☺

  12. Heya, could you get in contact with me on my email please, i would like to create a new monster, but i’m not exactly following you on your guide. I would like some help.

  13. “I assume I don’t have to explain how the Saving Throw DC was calculated for Pounce.”

    But, um… could you? DCs are one thing I struggle a lot with, and looking at this and the various monsters in the Manual… I have no idea. Many of them don’t match any ability modifier, with or without the addition of proficiency bonus, and have little more relationship with the chart on DMG 274.

    • Saving throws are all calculated as 8 + proficiency bonus + ability modifier, so in the case of pounce the prof bonus is +2 for a CR 4 monster and it’s based off strength 19 (+4) resulting in 8 + 2 + 4 = 14.

      Hope that helps.

  14. This is a fucking brilliant article. You’ve been a huge help, in all your works.

    Thank you!

  15. Great article, as always!

    What’s your thoughts about the PC facing enemies created with PHB class mechanics? In my campaign, the party is facing an army (more like an elite task force, actually) of paladins, and I’ve decided they’d be 6th level paladins (the party is 9th level), using the PHB paladin rules to make them feel more real. As I was building them, however, not only I’ve realized that they’d be extremely complex to play as a GM, but also they had very few hit points and a lot of damage potential, which could lead to situations like kill or be killed.

    Do you think it’s viable/balanced making enemies with PHB class levels, or should I just make regular enemies with the guidelines provided here and include some features and traits that resembles paladins?

    • Have you looked at your DMG in the DM’s workshop chapter, because it provides a method for that. I haven’t looked at it, but it’s in there.

      Also, Greater and mighty Angry, I am trying to make a Titan monster, but I’m having trouble understanding the Dice Codes. I was thinking it should be on size category bigger than the giant I’m basing it off of.

    • Personally I just make them up using the DM’s workshop, with the PHB open next to me to give me a guide on what to give them. Firstly because (as per the article) the first thing you want is your monsters CR, which you then adjust the stats to fit if possible.

      Secondly player characters are, by design, massive glass cannons compared to monsters. They also get far more abilities, and those abilities are balanced around encounters, short rests and long rests in a way that you don’t really need to your mobs.

      This is especially true for high nova damage classes (like paladins and assassins). Your players know what that character should be capable of. And you’ll either be having them act obviously dumb on purpose, or you’ll be wiping players right of the table.

      A 6th level devotion Paladin with STR 16/CHA 16 (hardly unreasonable) and a greatsword would burst up to 65ish damage in a single round. Sure, it’s a lot of their resources per day. But faced by a (higher level) player party that’s always going to be the right call. And with a +9 to hit. He’s then +9 to hit and 26ish damage per round after that. That’s an offensive CR of 7. He’s also go roughly 48 hp and AC probably 17. That’s a defensive CR of 1. So he’s technically CR 4 right now.

      You make him up, consult your charts and throw 4 of these guys at your 5 man party (the tougher members of which likely have hp in the 70s) as a deadly encounter.

      That is some serious rocket tag right there. Now of course that could be exactly what you want. God knows I once ran a campaign whose first session left my players terrified of goblin ninjas. On purpose.

      But you don’t want to end up there by accident.

    • “Attack of the Genericons”

      It won’t let me link it, but if you just click over to next week’s article, or seach, you’ll find it.

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