Building Better Monsters Part 3: Making the Monster Fit the Bill

by Bauxtehude (Liam Gallagher) on April 25, 2011

One thing that keeps coming up is the idea that monster design should be elegant, graceful, smooth and all these other flowery and juicy sounding words. What I mean to say in more direct terms is that your monster needs to realize its design goal with as little effort from you while DMing as possible. When your monster hits the grid and it’s time to throw initiative, the party is going to immediately do its best to murder your new creation. As a result your monster is going to have very little time to make a good impression.

In music one of the mistakes young musicians make all the time is not playing expressively. They practice a piece for ages before they perform it and come to know its subtleties and complexities very well, but their audience doesn’t. In order for people to understand the piece of music on first hearing the way that the musician has come to understand it over a period of weeks, the musician has to accentuate its good qualities so that they are readily apparent.

As the DM you have the very same problem with your monster. Any trimmings that don’t further your goal for the monster should be removed. Strip the monster down to what abilities it really need because it’s only going to get a few rounds of combat to use them.

“Perfection is achieved, not when there is nothing left to add, but when there is nothing left to take away.” – Antoine de Saint-Exupéry.

So you’ve got your idea for your monster and you know what you want it to do and how you want it to function in your game. It’s time to put those plans into action. There are a lot of considerations to be made and it can be daunting to figure out where to begin. My outlook is that the best place to start is anywhere. The following considerations are not placed in any special sequence. As you read each heading remember that you can never be too creative.

Powers and traits

These elements can get really complicated quick because they describe the manner in which the things your monster can do take place. That’s quite a burden. Think about your monster’s goal and have it realize that goal as easily as possible. If you just want your nine-headed, fire-breathing dolphin to burn people you don’t need a complicated power. Give it an attack score, make it do ongoing fire damage and call it a day. Obviously the scope of my marine friend is quite limited, but you might be designing a major villain for whom more considerations need to be made. The process will be the same however, just longer. Villains need survivability, they often need a way to escape. What kind of villain are you making? Would you design a power that allows their minions to take hits for them so that they can flee, or do they cast blink as often as they care to? It’s up to you!

Giving your creatures too many powers or traits

Power redundancy can take place quickly. Think about to my fire dolphin, even though spitting fire is the name of the game for it, it only needs one fire spitting power. If I had one power that only strikes a single target and deals a lot of damage, and one power that attacks a burst and does less damage, to me these are nearly the same power and any time I spend at the table considering exactly how the dolphin is going to spit fire is likely wasted time that I could be using to run the mechanical part of combat stupidly fast. I could be swayed to allow two types of fire attacks if they were really different enough but as is, fire burns, let’s move on.

Even if there aren’t redundant powers monsters can simply have more powers than they will live to use. If a monster dies before it has the chance to use the power the time that was taken to design that power was wasted. There may be a chance for the party to face this monsters again, which then will allow for it to demonstrate a greater degree of complexity (if the monster does indeed possess it) but otherwise trimming off unneeded powers will save resources. Beyond the effort, at every table I’ve ever played at space is at a premium.

Attack and damage scores

There’s a few ways to go about determining this number, but if you’re looking for a formula you’re not going to find it because it doesn’t exist. What I recommend is gathering some data from your players. First, to get your attack roll compile the defenses of your party and determine what the bonus to attack should be from that. How easily should your monster hit the toughest PC? The weakest? What will you need to roll in order to get a hit? Considering the type of monster it is, should it have a relatively high attack score for its level? If you’re worried about not having an acceptable base line to work from just open out your monster manual and take a look at similar creatures at similar levels.

Attacking which defense

Typically attacks that target AC are weapon attacks, things that have to pass through a PC’s armor to wound them. Fortitude attacks target a PC’s ability to withstand the effects of poison, extreme pain or to see if they can hold their ground. Reflex represents the PC’s ability to dodge or evade, while Will represents the ability of the PC to protect their mind or concentrate. Most attacks can be sensibly described as attacking any given defense. For example, fireballs typically attack Reflex. However there could be a strong argument made that the dolphin’s attack targets Fortitude. The volume of fire is so great that it is not a question of you getting burned or not, but instead how badly do you get burned. Maybe the swordsman is so skilled that armor is useless against his blade as he can place it where he wishes, instead the attack targets Reflex, and so on.

To determine the amount of damage the power should do many of the same considerations for the attack score can be made. Figure out how many hit points the people in the party have at had and then determine how many times they could take a hit from that attack (bearing in mind how often it will hit) and then go from there. Should this attack be a particularly devastating maneuver? Considerations for what the damage type should be are fairly straight forward. This is all covered in the DMG on pages 185 and 186 as well as the update (errata) online.

Further similar considerations can be made for the severity and variety of effects that creatures can impose. Remember the goal for your monster and do your best to realize it. There are a suite of conditions that you can impose upon the PCs, like daze and blind, but you are at liberty to make up anything you please. You can create effects that stipulate that a creature can’t see until in falls prone, that on its turn it must use its move action first, or that until the end of the next extended rest people find that creature confusing. The sky is the limit, bare in mind what you feel like adjudicating and what your players will tolerate from you and you’re golden.

Villains – threat and statistics

If your building a major villain it is tempting to give them incredible powers that drain levels from the PC and defenses in triple digets, but fighting such a villain is seldom satisfactory for a party. The threat of an enemy should be a combination of its abilities, the risk inherent in the scenario and the values of the party. Anyone can pound the number pad on their computer and then make that the monster’s damage roll, but it takes a skilled DM to actually make a monster frightening.


You can determine the defenses for your monster in much of the same way that you figured out its attack score. Consider what the monster’s goal is, consider the party’s attack scores and adjust accordingly. If you feel more comfortable working from a reference, you can find such a table on page 184 of the DMG.

Resistances, immunities and vulnerabilities

Fire creatures are typically resistant to fire damage, but you can create your own interesting resistances. How about a creature that takes less damage from an attack that also stuns or dazes it? How about a creature that has resistance against any creature that is shorter than it, or younger? While you might be thinking about your players flipping the table on you already, consider some of the works of fantasy you’ve read? An epic monster from a certain ring related book that can only be killed by women comes to mind. You options are only limited by your creativity.

In this area I like to take a que from Pokémon. To me if creatures have resistances to certain damage types they should have vulnerabilities elsewhere. Players usually feel good when they get to exploit a monster’s weakness, but that might not be what you have in mind for your monsters.

Ability scores and skills

Thankfully these stats work the same way that the PC equivalent do. What skills does your monster need to accomplish your goal? Say you have a cat burglar, and your goal for her is that she’s actually a very poor thief. It only makes sense that she’s all thumbs (Dex of 9) and isn’t trained in Thievery. In order to figure out what the actual scores are for each stat you can do what you did for defenses and attack scores.

In the April 6, 2011, Wizard’s of the Coast D&D podcast game designer Jeremy Crawford let the cat out of the bag on the relationship between ability scores and attack and damage bonuses. He explained that while designing monsters the R&D teams determine the attack score by level and then adjust that score through play testing. This is a very practical approach and it’s the one I use. Any attempt to produce an accurate formula for monster stats will leave you like the Romans with their Gregorian Calendar, wondering why it’s snowing in August.

Monster level

What threat level should this creature present to the party? Is this a heroic, paragon or epic creature? Picking the level for your creature is a hard consideration as any experienced DM will note that the power level of monsters within a level ranges wildly with variables like what monsters the creature is pared with, the terrain involved in a combat, and if it is a social interaction, how well the creature is situated in society. I recommend trusting your gut and extensive use of trail and error until you get a good feel for what your party is capable of. For me, an elite monster should be able to beat the crap out of a single PC of the same level, but the PC should come out on top in the end.

D&D math and XP

As discussed in Building Better Monsters Part 2, experience points serve two purposes in D&D. They determine when PCs get to level and how much XP a DM has to spend on an encounter of a given level.

An experience point can be the base unit that is used to progress characters from level to level. In this way it generally represents the growth of PCs, be that physical training, book learning or elderitch embudement. XP is typically gained by overcoming monsters or overcoming skill challenges, though many DMs dole out the XP in their own way.

In 4e, XP has been tasked with budgeting combat encounters; monsters have an XP value that’s determined by a ratio between it and the number of XP needed to get to the next level. A PCs needs 1,000 XP between level one and two, so if you have a party of 6, that means (given an equal distribution of XP) the party will need to earn 6,000 XP before they reach level 2. The experience math of D&D assumes that there is going to be 10 encounters between each level. A level 1 encounter has a 600 XP budget (for a party of six). This means that a level 1 PC needs to defeat 10 level 1 monsters to reach level 2. This 10:1 ratio continues through all levels. You can compare the tables on pages 56 of the DMG and 29 of the PHB to affirm these findings.

Monsters have an XP value and they also have distinct parts: powers, ability scores etc. so it only seems sensible to suggest that each of these things ought to have a proportion of that XP value associated with the monster, right? The answer is an unhelpful “Maybe?”. When XP is thought about in this way it implies a point-buy system, such as buying ability scores in D&D. There’s a large stumbling block to this approach in that one has to arrive at the absolute values of many game mechanics that will forever remain elusive.

Initially you would have to determine the exact value of an experience point and how much threat it would represent to a PC. After that you would have to be able to chart the progression of a PC’s power level, incorporating spikes in your curve for levels where the PCs gain daily powers, paragon path or epic destiny features. Though it would tempting to assign a high XP value to a melee attack that does 40d12 + 90 damage, if that damage is assigned to a monster with no move speed it’s going to spend a lot of time waiting for a PC to waltz by. But what if there was a controller in the encounter who could push the PCs? Already things are getting complicated, without comparing the relative attack and defense scores of our two monsters and PCs, or any reactions they might take.

There are too many things to buy points with to anticipate the way that they will interact and so associating an absolute value to a point, while not impossible is infeasible. In the case of building monsters the DM is better off comparing their monster to similar monsters of the same level and then eyeballing the final product. Though the creation of a point-buy system could help DMs ballpark their ballpark figures, the complexity required of such a system would far surpass the complexity of the job with which it is tasked.

D&D math isn’t really math because the numbers that are being worked with are not known variables. The numbers and figures are loose to give more power to the DMs, as it is the DM’s job to tell a story, not to realize mathematical equations. As is demonstrated in the aforementioned podcast and the DMG, the attack score of a monster is Level + 3 + whatever the game designer thinks is best. These conditions are not the basis of accurate mathematical modeling.

Personally I think the XP is a useless unit, and in my years as a DM I have never tracked or awarded a single experience point. I find XP to be a useless statistic that only adds to the amount of book keeping required, and only encourages meta game thinking in players. The PCs should level when it is appropriate for them to do so in game, and monsters should have the abilities and the powers that are sensible for them to have given the storyline.

Synergy in layout and format

Though the way some stat elements can affect others it is most evident with powers and traits, these relationships can flow through the stat block in other ways. In the end the only sense in having a stat block at all is to help you run monsters in your game; the stat block is there to serve your end goal and should be treated as such.

Reformat, omit and expand upon the presentation of the stat block until it suits your needs. As an example I never write out a monster’s equipment as I feel all that information is contained within its powers and its defenses. I typically skip alignment as well because I like to decide the disposition of NPCs on a case-by-case basis. These stat elements, along with others are removed from the stat block to save me time and space. Feel free to create your own stat block style.

Prep time required

the amount of work a DM has to do is considerable, and while custom building monsters for a campaign will give the DM greater control over the style of game it can be very time consuming. Monster stat blocks that are whittled down to their basics will be much quicker to build and will require less rereading when their time comes.

Listen to the party

There is no substitute for play testing and your party can give you invaluable advice and criticisms. They are in a unique position to give you first hand accounts which will be of more use to you than any guide I could write. Your players are your target audience, and despite whatever grand designs you may have for your campaign you should never forget that without them you are nothing. If you milkshake doesn’t bring the boys to the yard you have to cancel the game and all your planning was for not.

Don’t listen to the party

At the end of the day you’re the DM, you write the adventure, you make the monsters and give voice to the NPCs. You have to produce sessions that you can run with confidence and you have to tell your story. Remember, you’re not running for government office so you don’t have to do what they want you too. Being the DM is not a committee process, and the players are not in the position to give you advice on what the game should be like because they don’t know what you have planned, and in many cases it is important that they don’t know for the game to run. Trust your judgment, do your best, and if you catch flack for it, find people who are less mean spirited to play with.

So there’s a very long list of considerations you will need to make in order to design your monster. How has your monster design progressed? Let me know of any stumbling blocks you’ve encountered and how you might overcome them. In Building Better Monsters Part 4, I’ll cover the issue of themeing, building monsters that fit into encounters and the campaign setting at large.

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1 Alphastream April 25, 2011 at 12:58 pm

Great points on having too many powers. Having fewer powers can make the monster more memorable. It has these flaming fists, and everything they touch catches on fire. For non-boss monsters it can be superior to have a single memorable attack and then ham it up when you run the game.

For creatures that should be dynamic, such as many bosses, a range of powers communicates the flexibility and power they have. This works well for intelligent boss foes that should have PC-like flexibility.

Nice series, thanks!

2 Dave April 26, 2011 at 1:27 pm

Macbeth resistance: none of woman born shall harm you.

[enter Macduff]

3 skallawag April 28, 2011 at 1:11 pm

I personally don’t agree with your “Don’t listen to the party” section. You may as well DM to yourself in a vacuum. This and you pretty much contradict your “Listen to the party” section.

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