The fifth edition of Dungeons & Dragons is a game that has been catapulted into staggering popularity in the years since its initial release in 2014. While people have adapted the game to suit a variety of purposes, the game is really not meant to be a catch-all for your table’s roleplaying needs. Or, at the very least, it’s certainly not designed that way. Its rules and mechanics betray the game’s wargaming roots, as well as its history as a dungeon-crawler. For example, why do we still have all of this adventuring gear that almost never comes up in modern play? And though some might disagree on this final point, it doesn’t naturally encourage the kind of heroic, high fantasy, narrative-focused roleplaying that so many (myself included) try to push it towards.

If you’re running a largely combat-focused game, however, it’s great. That is, of course, assuming you’re running a standard encounter involving a party of about 4-5 players and a small group of enemies that contains one or two more threatening monsters along with some cannon fodder. But what if your entire campaign is designed around combat encounters involving only one or two monsters most of the time? If, like some of my friends, your immediate thought is, “But the game isn’t built for that!”, well, you’re absolutely right. It really isn’t, but I didn’t realize just how poorly it handles these scenarios until I was already in the thick of it.

I like writing a bit too much, and I wouldn’t necessarily expect someone to read all of this in one go, so here’s a table of contents to help you out:

1. Preface: Campaign Background
2. Part I: Spicing Things Up
3. Part II: Action Economy
4. Part III: Strategic Movement
5. Part IV: Miscellany
6. Conclusion

In the preface, I go over the campaign I’m running to provide the context under which I’m designing these monsters. In Part I, we look at how I took a simple monster and made it more challenging for a group of low-level player characters. Next, in Part II and Part III, we examine monsters that are meant to go toe-to-toe with a full party of mid-level heroes. Finally, in Part IV, we cover a few extra tidbits, including my personal spin-off of the dreaded legendary resistance.

Preface: Campaign Background

Before we get into any specific monster design choices, I want to give a bit of background on the campaign I’m running just so that there’ll be fewer things to explain later on. First and foremost, this is a homebrewed campaign. While I did nick bits and pieces from other sources, as any good GM does, the general arc of the adventure as well as the majority of encounters therein are made from scratch by yours truly, for better or worse. The world itself is also custom-made, though in this case I appropriated a lot of geography, maps, NPCs, and gods from other settings. I did this primarily because I wanted my players to be able to experience a wide variety of biomes within a single campaign without having to make their characters take extraordinarily long journeys to get from one to the other (or do a lot of plane-hopping).

As for the monsters, most of them are ripped straight from the Monster Hunter series, in which combat typically consists of 1-4 players battling a single monster at a time. While I do use some of your bog-standard D&D monsters, particularly for generic NPCs, most of the stat-blocks for major encounters are custom-made as well. The reasons for this will hopefully become clear later on, but the important thing to note is that you won’t see any of your usual skeletons, kobolds, or mindflayers in this post.

We should also talk briefly about loot. Any good D&D game involves the players acquiring better gear throughout the campaign, in the form of both mundane and magical items, and these can have a sizeable effect on their success or failure in encounters. As with other things, while I am using some standard equipment, there are relatively few “by the book” magic items in the game. The reasoning for this is that I’m using a custom loot system where, in the spirit of Monster Hunter, the party carves parts from monsters they kill to make upgrades for their equipment. My players are just as overpowered as any artifact-laden character in a standard game (maybe more-so), but not necessarily in the same ways.

To put things plainly, you should take everything after this paragraph with a grain of salt. While it’s true that D&D isn’t designed for single-monster encounters, some of the specific stat blocks presented here might very well TPK a party of the appropriate level in a standard D&D campaign. The general principles I used to construct/modify these monsters should still hold true, however.

[Major thanks to Amellwind, creator of the behemoth-sized homebrew tome known as the Monster Hunter Monster Manual, without whom this campaign wouldn’t have been possible!]

Part I: Spicing Things Up

Let’s start off with a low CR monster from the basic rules to see where problems start to arise when designing encounters with single monsters. We’re going to ignore monsters that are clearly meant to be fought in packs, such as anything below CR 1, and for that matter, we can also safely ignore anything below CR 2 since in the first level of the game, a stiff breeze can kill anyone with low hit-points or low AC in your party. Here’s a familiar CR 2 beast, the giant boar:

All in all, the giant boar is a pretty basic monster, but it does have a few things going for it. It does a decent amount of damage per attack for a CR 2 creature, and does more damage if it manages to charge a creature. Would it pose a challenge for a group of 4-5 level 2 player characters? Well, let’s assume for the moment that it has everything going for it: it acts first, it manages to get enough distance between it and the party to activate its Charge, and lands its Tusk attack. It can probably down one party member on its turn, but assuming the party is similarly successful (they land all of their attacks and spells), it’ll likely go down before it manages to act on its next turn.

[We’ll use this same assumption (that all attacks and spells are successful) going forward, as it makes the math much easier and gives us an accurate picture of what combat will be like, if not how many rounds it will take.]

It does have Relentless, which lets it survive another round if it takes 10 damage or less, but it’s not very likely to get its Charge off again without dying in the process. It would need to move away from the party to do so (provoking opportunity attacks from any melee combatants), so with only its vanilla Tusk attack it only has a so-so chance of actually posing a threat during that round. If the boar had some backup, it could pose a threat, but on its own it’s not going to be very effective.

Generally, once you’re past first level, it’s better to throw more at your players than you think they can handle, as it’s a lot easier to adjust downward than upward mid-battle. How the monsters behave has a large impact on how dangerous they are, and your players likely don’t know the exact stats and actions of your monsters, so you can always leave some of your more dangerous options off the table if the monster is already proving to be deadly enough without them. So, let’s assume that even if we add a few minions, we still want a better boar. What can we do? Let’s see how Amellwind’s Monster Manual handles Bulldrome, Monster Hunter’s version of the giant boar:

There are a couple minor changes here, such as slightly increased hit points (maybe enough to let this boar last another round), but its Relentless property has been removed, so that’s probably a net zero gain. The bigger changes are in its additional actions, notably Thrash. While the DC for the dexterity save is not insurmountable, if the boar finds itself in the thick of it, it has a decent chance of hitting at least one or two characters with this action. More importantly, the knowledge that the boar can deal area-of-effect damage (which your players rightfully would not expect from a CR 2 beast) might be enough to make them reconsider ganging up on the creature.

If any players choose to move away, even if they disengage and only move slightly out of range, the boar’s new Aggressive bonus action means it has plenty of opportunity to position itself for another charge. It may not be worth it, given the boar only has slightly more hit points and is still prone to opportunity attacks, but it’s an improvement at least.

Though I can understand the rationale behind its removal, I did like the flavor of Relentless, and leaned into that even more with my version:

Relentless is back, the boar has even more hit points, and better damage and hit chance on its tusk. Plus, players are in for a surprise once they’ve bloodied it. Blood Rage makes the boar more likely to succeed when wounded, all but guaranteeing a climactic end to the battle.

Notably, the boar can still only attack once per turn, and its Thrash is still only recharges on a 5-6, so while threatening, the boar isn’t likely to utterly wipe out the party, particularly if they have healing and use it, which most parties do.

Let’s summarize the changes made since the original giant boar:

• Thrash lets it deal damage to multiple combatants at once, making the party reconsider their positioning.
• Aggressive gives the boar more opportunities to make use of its Charge.
• Blood Rage combined with the pre-existing Relentless makes the combat more intense as it goes on.
• More hit points means it will last longer, giving it more opportunities to do cool stuff, but the party can still hit it easily.

I mention the increased hit points last because, while often necessary for boss monsters, blindly increasing hit points without giving the monster interesting things to do that the party hasn’t seen yet just makes for dull combat.

I upped the boar’s CR to 3 to compensate for all these changes, but if I recall correctly, even at level 2 the party was still able to deal with it fairly effectively. I did consider modifying Aggressive to let the boar avoid opportunity attacks, but it’s only a CR 3 creature and I have to draw the line somewhere (ostensibly). The boar as originally designed would not have posed much of a threat to them but this variant, which they stumbled upon in the smoking ruins of a town recently ransacked by gnolls, proved to be an exciting encounter for them.

Part II: Action Economy

At this point, you’re probably thinking something along the lines of: “If a CR 2 boar needed all those changes to make it viable as a single monster encounter, I don’t even want to know what sorcery you had to inflict on higher CR creatures.” To that point, (1) you’re right, tuning and re-tuning monsters like this is a lot of work and (2) I’m going to tell you about it anyway.

We’ll be using Rathalos as an example for this section since we can’t very well have a D&D post without flying, fire-breathing monsters. This monster served as one of several boss monsters that my players encountered (in succession, not all at once) during the climactic end of the first half of the campaign. At the time they were level 6, but had help in the form of a demon hunter NPC, as well as an elderly monster they had rescued of similar size and power to this Rathalos, though on its last legs in more than one sense. The party’s monster friend passed a way (a tragic moment), but the party otherwise succeeded in slaying the Rathalos. This bought the capital city, now in flames with its main gates battered nearly to pieces by the encroaching hordes, some much-needed time to evacuate.

Rather than go through several stages as we did for Bulldrome, I’m just going to show you the end product and explain the rationale behind what might seem absurd for a modern D&D monster:

This stat block makes use of a design philosophy known as “Action-Oriented Monsters.” I picked this up from Matt Colville over at MCDM, though it’s possible the concept may have origins elsewhere. Essentially, the goal is to ramp up the intensity of the encounter through the use of unique monster-specific actions that can radically alter the tide of battle.

The primary way that this is accomplished is through “villain actions,” a variant of the “legendary actions” originally found in standard D&D monsters. While standard monsters can and often do have interesting actions to take, they usually have to be done during the monster’s turn, which means the monster often has to choose between attacking and doing more interesting. If the action fails, you’ve just wasted your turn, which is especially unfortunate if this is the only monster in the combat.

Villain actions, by contrast, can be used out-of-turn, just like legendary actions. The ability to act out of turn is a necessity for any boss monster, particularly if that monster is meant to fight the party without the assistance of other creatures. Without this, monsters that should theoretically be on par with the players (or slightly above) will struggle severely due to the simple fact that they can’t act or move nearly as often as the players can.

Legendary Actions vs. Villain Actions

Why not just use legendary actions, you ask? Well, if you look at the stat blocks for monsters with legendary actions you’ll notice that these actions are typically some combination of:

• Make an attack
• Move, sometimes without provoking
• Make a perception check

If you’re lucky, you might even get to cast a spell using a legendary action (gasp!). These are all moderately useful, but they’re not particularly interesting or dramatic. Villain actions are much more impactful by design, which you can see by comparing the above options to the villain actions in Rathalos’ stat block.

To balance out their power, villain actions have a limited number of uses. The typical wording is, as written above, “[the monster] can take each [villain] action only once during an encounter.” In my experience, the ability to use them out-of-turn more than makes up for this.

I’ve ignored the single-use rule at times to increase the tension further when I feel like things aren’t quite dangerous enough, but the point is that you’re not using them as often as legendary actions. As I mentioned before, dialing things back through monster behavior is much easier (and feels less fraudulent to me) than deciding to give a monster more hit points or suddenly introducing reinforcements mid-battle. A more reasonable wording might be “only twice during an encounter,” but your mileage may vary.

Recharge Actions vs. Villain Actions

Most dragons in D&D have a massively dangerous breath weapon that requires rolling a 5-6 on d6 to recharge. For Rathalos, its Fire Breath is a villain action instead, which has a couple of benefits:

1. Monster doesn’t need to choose between attacking and using its breath weapon.
2. Breath weapon is still limited use, but not tied to a finicky dice roll.
3. Since villain actions occur after another creature’s turn, you have more choices of when to unleash it.

Even if you stick to the one-use limitation of villain actions, the Rathalos also has Savage Fire Bolt, which gives you a similar flavor albeit with less devastating results, and has the advantage of being an attack roll (which the Rathalos will probably hit with) plus an area-of-effect, err… effect.

Fear Effects

Dragons in D&D often have auras that make you afraid, which makes sense thematically, but I’ve always found the frightened condition to be more annoying than interesting. Here it is as written:

• A frightened creature has disadvantage on ability checks and attack rolls while the source of its fear is within line of sight.
• The creature can’t willingly move closer to the source of its fear.

Instead of encouraging you to move differently, it just straight up prevents you from moving in specific directions, and having disadvantage on attacks just means the combat is going to go on longer… which, even if you like combat, doesn’t necessarily mean the combat will be more interesting as a result. Either of these alone is bad enough, but together it’s downright debilitating. Making one side less effective without making the other side more effective doesn’t really make things more dramatic.

I’m not saying we need to write it out of the game, but AOE fear effects are a bridge too far for me. Not to mention, most dragons’ fear aura is a passive effect rather than an action that they take. Instead, Rathalos gets a single-target fear effect (Withering Gaze) as a bonus action. More stuff for Rathalos to do, plus you get to narrate the Rathalos giving one of your players a furious, smoldering look.

For AOE crowd control, Rathalos still has options via Savage Roar, which is a stun rather than a fear effect, giving Rathalos a clear advantage in combat against anyone that falls prey to it.

Punishing Melee Attackers

Rathalos has plenty of options for dealing with ranged attackers, from his 60 ft. flying speed to his ranged fire-based attacks, but it can be difficult to catch savvy fighters who like to put the monster between them and the rest of the party and have enough hit points to withstand an attack or two. Flying is great, but doing it without provoking once your monster has engaged with the party’s melee attackers can be a tricky proposition.

This is where our two remaining actions come into play:

• Air Drop (villain action): Gives Rathalos a free attack against a creature within melee range, gives it a way to fly while grappling a creature that might otherwise try for an opportunity attack, plus additional damage to one or more creatures from the ensuing fall.
• Snapping Jaws (reaction): Damages melee attackers, potentially causing them to rethink standing next to the Rathalos the whole time.

These give us more damage, movement options, and most importantly can force the players to reconsider some of their usual tactics.

Summary

So, do we have a monster that can effectively battle a whole party? Let’s take a look. Rathalos…

• Has bonus actions, reactions, “legendary” actions to make the most of his time on the battlefield.
• Has dramatic actions that can alter the tide of battle at nearly any time.
• Has options for dealing with melee and ranged attackers.
• Can take a beating while dealing out hefty damage.

While there’s nothing that can guarantee that a combat will go the way you expect, monsters that have all of these things going for them stand a much better chance of creating a dynamic, high-energy combat experience for your players.

Part III: Strategic Movement

By the time your party hits level 9 or so, your melee-focused party members are going to be pretty hard to take down due to high AC from a combination of Dexterity, equipment, magic items, healing from other party members, and of course nine levels of hit points. While flanking can give melee characters a reason to move around to a degree, there’s not much of a reason for them to move otherwise if they’re only attacking a single target.

Environmental hazards and secondary objectives can help a lot with this, and I highly encourage incorporating those into your encounters, but this post will be focusing strictly on monster design, as there are plenty of other resources that can help with other aspects of encounters that can be applied to more varied mixes of monsters.

As with the previous section, we’ll only be looking at the final version of one of my monsters:

We’ll ignore most of the action economy for this monster – it follows the same guidelines as Rathalos – and focus on the new Monster Parts property. The core loop of the Monster Hunter series involves hunting monsters to harvest monster parts to create better gear to fight more difficult monsters, etc., ad nauseum. Reliably getting specific monster parts often requires targeting specific parts of the monster, which are vulnerable or resistant to different types of damage. This not only encourages players to move around, but also to choose weapons or group up with others with different weapons based on what parts they need to break.

In Amellwind’s Monster Hunter rules for D&D, things work a bit differently, as which parts you get are primarily based on a random roll on a loot table. Even so, for melee attackers, having different areas of the monster resist different types of damage is still useful to encourage more varied positioning. In my experience, it worked quite well, and made combat more interesting for the price of some additional bookkeeping on the part of the GM (I just used tally-marks in a notepad document) and the need for called shots when players made attack rolls. Tracking the facing direction of a monster isn’t something that’s natively supported by most VTT platforms, so that was another wrinkle that had to be ironed out.

As a disclaimer, in the third and final act of the campaign, I ended up abandoning this part-breaking mechanic for a number of reasons. One of these was that my monster facing direction tracker in Roll20 would only work intermittently, which I suspect is more an issue with Roll20’s scripting sandbox than with the custom script that handles that particular feature. Another was that the encounters in the final act shifted towards more standard D&D fare, incorporating soldiers of enemy factions as backup for the boss enemies and monsters that the party was facing. With more enemies to keep track of, trying to then also manage extra data for monsters was too much overhead for this GM.

Still, if you’re looking for more strategic combat against large monsters that doesn’t require too much additional overhead, I think this is an option that’s worth exploring at your table.

Part IV: Miscellany

When we talked about Villain Actions earlier, we mostly discussed them as a replacement for legendary actions, but there’s technically no reason you can’t have both. As long as villain actions remain limited in use and legendary actions remain limited in power, they’re different enough mechanically that they can work in concert. Some of the most powerful, high CR monsters I designed for my campaign employ both of them to great effect.

We’ve also ignored spellcasting monsters, since my Monster Hunter campaign understandably features relatively few of them, and having to look up an entire tome’s worth of spells while running a combat is one of my least favorite activities. In addition, while spellcasters can make formidable opponents due to their versatility, they tend to fall rather easily when swarmed due to their typically low AC and hit points.

Finally, we should also probably at least mention Legendary Resistance, a common but contentious feature of many legendary D&D monsters that lets them ignore a limited number of failed saving throws. Without it or something like it, even high CR monsters can have difficulty dealing with all the crowd-control effects that high level players can employ, but it’s often annoying to fight against it as a player. You can find good alternatives to this in the monsters designed by MCDM (look to their upcoming monster book, Flee Mortals!, in particular), but I’ll offer my custom variant of it in case you find it useful and more palatable than the original rules:

With this change, your players’ actions and spells will have a decent chance of being successful when they are first used, assuming the monster isn’t particularly resistant to the specific effect, but will have less success on subsequent uses. Rising Resistance is far less binary than legendary resistance, and also harder to game the system since it’s not something that severely limited in its number of uses. Not coincidently, this also models how monster resistances work in Monster Hunter. It does require a bit more book-keeping, but you probably won’t have more than one legendary monster in a single combat, which makes it doable.

Conclusion

In this post, we looked at a number of ways to spice up your monsters, give your monsters a fighting chance against a group of player characters, and encourage your players to think more strategically about their movement in combat against these monsters. This is not meant to be an all-encompassing guide to encounters, but rather a collection of examples and suggestions for making monsters more interesting and dramatic in situations where it’s one monster vs. the party.

And that’s it! Thanks for reading, and I hope you found some bit of this useful or insightful.

Peace and TTFN!