I have bigger, better articles in the works but I noticed my output has slowed down, so back into the vaults I go. I've dug up this list from many years ago and adapted it. This was inspired by a recent claim I made that there's such a thing as "system-agnostic combat encounter design" that you can and should learn, which many people were resistant to. Here was the original pitch I wrote for this:
I've talked to many people who think that combat in 5E isn’t really fun. There are many arguments for this, some of which are perfectly valid and some of which just come down to subjectivity, but by far the most common argument is this: they say that because it removed so many mechanical elements from the process (e.g. flanking mechanics, using miniatures and grids by default, having to take feats and shit to move in conjunction with an attack, having to spend actions on drawing weapons and reloading crossbows and shit, no full-round attacks, etc.) that there aren’t enough options in combat to keep it interesting. And they say that, because of this, every combat is just, “I make a basic attack. ...I hit. …alright I attack again. ...I hit. ...alright I attack again. ...I missed" for like 10 rounds.
But I can’t say that I agree. My own group doesn’t have this problem and it’s not like we're working that hard to avoid it, either. No, it doesn't have a bunch of "cool power buttons" to press like 3.5E and 4E. But you still can do all sorts of creative things as long as you think of something useful and cool other than “basic attack,” and the DM thinks they can run with it.
The goal of 4E D&D was to have the rules do all the heavy-lifting for you. It has intrinsic tactical depth, but the effort they put into that came at the expense of pretty much everything else. 5E asks you to put in some extra work if you want to have an action-oriented adventure, but it does so because it's also granting you the freedom of tactical infinity.
To put it shortly, are you really all that surprised that your combat hasn't been fun when you keep throwing your players against 5 regular goblins in a blank, flat room with no secondary goals or complications to the situation? Doesn't it feel a little silly to blame the rules when that ends up being a boring experience?
Of course, I know you believe me. You know what I'm talking about. There've been many other writers who've developed some theory as to what makes this work. Chris McDowall has "Information, Choice, Impact." Patrick Stuart has "Game vs Threat" (found in his book Silent Titans. [EDIT: I've decided to just splice the page in at the bottom of this post since it was bugging me that I couldn't find anything about it on his blog]). The Monsters Know What They're Doing has made a career of their theory. Runehammer has a great series on "Room Design" that covers what I'm talking about. 4th Edition D&D made use of one of my favorite game design concepts innovated by DOOM: "Orthogonal Unit Differentiation" (watch that video, it rocks). I even once claimed that there are literally only two enemies you ever need (which is a lie, but a good lie).
But this was my own effort from years ago that I think holds up pretty well. It's just a list. Not a theory or a formula, just a list of elements to include.
I split this into three categories:
- Stuff that's interesting about the monsters
- Stuff that's interesting about the environment
- Stuff that's interesting about the situation
Sometimes there's overlap. You should make sure you have something from at least two categories in every combat, if possible. These lists are by no means exhaustive, but if you plunder from each of them a few times then you'll see their value and you'll begin to develop your own ideas that aren't included in them.
This is the least valuable list because if you're playing a combat-focused game then it probably already comes with monsters that have this stuff built in (hopefully). There are basic tools like giving them immunities, vulnerabilities, legendary actions, etc. but I'm going to list ones that aren't necessarily going to show up in your game on their own just by always picking the most common options, and which you might need to add in yourself if the monster stat blocks are too boring.
- Uses teamwork. Give the monsters some devastating combo but have it rely on multiple participants to work. One shoves the PC prone and the other attacks. One dumps a bucket of tar on the PC and the other lights them up. Two run past the PC on either side holding a net outstretched between them, and a third comes up to beat on the PC while they're struggling with the net.
- Rides a mount. PCs may or may not have their own mounts. Provide ample space and do some hit-n-runs and some tramples.
- Regenerates health. I've run trolls in D&D before and they don't take it nearly far enough. Faster, better regen if you want it to make a difference.
- Oozes. Okay this one isn't a trait but use more oozes goddammit. Oozes are like halfway between a combatant and an environmental hazard.When you fight an ooze, it hurts you not with an attack, but by passively occupying your space. Therefore, your safety is dependent on maintaining distance while still being able to effectively harm it yourself. An interesting positioning-based tactic is built in already. And to make matters worse, physical blows against an ooze are often rendered ineffective by its properties, forcing the players to find tactics specialized for use against oozes. Maybe they corrode weapons that hit them. Maybe they suck it up and then your weapon is stuck inside. Maybe they split apart when struck and now there are two oozes. Maybe they're just springy and your blows bounce right off. Swarms have a lot of similar properties to oozes, too.
- Reacting weirdly in general. Undead healing from necrotic damage, nilbogs causing things to happen the opposite way, a creature that explodes upon death, etc.
- Many illusions. Prolong a fight by having lots of false targets, but also give a clue to what's real so astute PCs can be strategic.
- Attacks can cripple. If you aren't already using a rule system that has injuries, then you can make them a part of some monster's specific attack.
- Can read minds. Embrace metagaming with a diegetic justification for doing so.
- Causes confusion. Don't overdo it, but just a couple PCs being struck by one round of confusion can cause chaos.
- Has a weak point. "Called shot" mechanics are a can of worms but I think it's easy enough to just say, "the monster has a gem on its forehead, it's assumed that your attacks won't be very effective unless you specify that you're targetting the gem, which has a higher AC than the rest of the monster because it's tiny."
- Eats PCs. Remember when you were a kid and all monsters' goals were just to eat you? This works a lot better if you have the monster do it mid-battle instead of waiting until their prey is killed. Don't have the PC automatically be dead once swallowed, though. Give them a fighting chance to either cut their way out (if the monster is gargantuan) or at least sit tight while waiting for their friends to liberate them.
- Basically anything that turns the fight into somewhat of a puzzle. A monster that can only be destroyed based on what time it is/what round it is (e.g. every 4th round, and you have a little 4-section clock somewhere in the room that updates each round in front of the players). A monster that turns into stone between every one of its turns so you can’t do much (if any) damage to it unless you find an opportunity to attack it on its own turn. A monster whose body is separated from the source of its stats (e.g. they can only be damaged by attacking a magic stone on a pedestal in the room, or they perceive things through an eyeball on the wall). A monster that attacks PCs in dreams, so they’re vulnerable when asleep. Be creative.
- Grapples. This is a really nice alternative attack to just straight damage dealing. It still incapacitates the PC and can lead into other forms of damage. Maybe the monster does at-will damage to anyone they're grappling, meaning that the consequence of being hit by the monster is delayed but will be ongoing if you don't counter it. Maybe the monster throws you, and you either take fall damage or damage from something you're thrown into. Maybe the grapple can be a setup for something more devastating than a mere club or axe can inflict, but the PC has at least one round to respond and escape somehow. And any round where they're doing something other than a basic attack is usually a good sign.
- Multiple pools of HP. Imagine a huge, huge hydra where each head has its own HP and are killed separately.
- Multiple waves of enemies. Bonus points for telegraphing each wave.
- Rises as undead. Similar to multiple waves but the monster should meaningfully change somehow once in its "undead" form. Alternatively, the rising might be delayed until after the PCs leave, and so later on in the adventure they encounter the same enemies but now as zombies/ghosts/whatever and are like "what the fuck??" Maybe it's further down the line or maybe it's just a couple rooms later!
- In fact, any way to give it multiple phases. I tend to prefer shorter combats anyway so something complicated like a boss monster that unlocks new attacks after certain damage thresholds or who takes on 3 different forms or something like that is probably out of the question for me. But at least one big before-and-after event that changes the situation significantly can add a lot. Either that or several smaller changes that are easier to implement, like a monster that mutates slightly every round.
- Frightens the PC. This one might be controversial but I genuinely enjoy fear effects. A lot of purists deride any possibility for the PCs' agency to be compromised or for you to "tell them what their character is thinking" (a debate that I personally feel is kinda dumb, but that's a fight for another day). However, I would counter that 1) fear effects can make for interesting gameplay if they force the PC to make different decisions than they normally would, and 2) it's a great example of a negative consequence to inflict on a PC other than dealing damage. Here's a Reddit post that talked a bit about it.
- Petrifies (slowly). Insant petrification is kind of shitty. Instead, you should make it implement in stages each round. First phase, halve the PC's speed. Second phase, limit them only to moving or taking an action, not both. Third phase, make them have disadvantage on physical checks. Then, finally, you can petrify them. Give them a method of curing themselves before its too late so they can use their diminished abilities in those petrification rounds to frantically try to prevent the condition from cementing.
- Similarly, mutates the PC. Imagine a monster whose most basic attack is to just inflict its target with a minor but impeding mutation. Roll to hit, boom - thumb growing from your palm now. Disadvantage on all checks requiring your hand until you cut off that extra thumb. Roll to hit, boom - gain 6 more eyeballs around your body that completely disorient you.
- Relies on unconventional senses. Blind monsters who rely on sound or smell are obviously a fun thing to play with (see Veins of the Earth as well as A Quiet Place), while a personal favorite of mine is "tremorsense" (since I like burrowing monsters). Truesight is less interesting than most options, but something like infravision can be neat since PCs can come up with ways to trick that (see Predator). There are many more weird and obscure ones you could try gamifying if you think they have potential. Echolocation (distinct from Hearing Perception, because the creature is creating their own sound to use as feedback and create a mental 3D image from it), sensing electric fields (electroreception), sensing magnetic fields (magnetoreception), sensing based on moisture in the environment (hygroreception), sensing pressure in the air/water, etc.
- Telegraphs their next move. Rears up a big axe swing, or stomps before it charges, or summons a bunch of power before casting a spell, etc. If the move they're about to do is too mundane, then all this technique serves to do is undermine their ability to actually get the PCs with it. Thus, the move should be something big and which demands immediate action to avoid or counter, so that way you can justify granting the PCs a full round of anticipation to deal with it somehow. It can be nice if the windup also has a lesser effect of its own. For example, imagine a dragon that's about to breathe fire takes a whole round to breathe in beforehand, but the act of breathing in also pulls a bunch of PCs and objects closer towards them (thus positioning them closer to where the line of fire will end up being).
- Has social relationships. Maybe the group of monsters has a visible hierarchy, and PCs can be more or less effective if they target the leadership. Maybe there's a small monster that is beloved by a big monster, who’ll be protective and defensive while small target is alive but then go berserk if small target is killed. Maybe there's a monster that all the other monsters want to impress and if you can just get them to embarass themselves then the whole fighting force falls apart.
- Wants something. The classic example is the Rust Monster. It doesn't want to hurt you, it just wants to eat your metal. Once you understand them, you realize that you don't have to fight them at all. Just drop a crowbar or frying pan for them. You could have monsters that want water, money, specific information, the opportunity to demonstrate something, whatever.
- Controls the PC. Either by charming them, mind-controlling them, or something else, the PC spends part or all of the fight working for the enemy. This is such a simple trick but it's excellent. The party is down one whole member, they're fighting against someone who is likely quite a bit more potent than any monster of their designated CR, and they have to find a way to neutralize the threat without killing their ally. You could also make it some NPC ally to the party if you're worried this goes too far, or you could make a whole group of enemies be a bunch of mind-controlled innocents. What would your party do to protect civilian noncombatants, especially when those are the threat the party faces?
Whereas you can take most of the monster suggestions and put them into the monster statblocks that you'll be dropping into your game, the environmental traits I list below are probably going to have to be decided on ahead of time as you sculpt areas of play like dungeon rooms. You could make some random tables to generate these on the spot and then insert them into whatever combat breaks out mid-session, but a lot of them work best when they have some forethought and are chosen specifically to fit the greater location they're used within.
- Difficult terrain. This can take the classic form of brambles and ground foliage, halving all movement speed. But there are lots of kinds of difficult terrain. Mud that leaves tracks, webs or quicksand that suck you in, ice floors lacking in friction (DEX check or you move an extra 5 or 10 feet in the direction you were moving), etc.
- Hazardous ground. Spikes, thorns, fire pits, and other insta-damage areas of floor. If those sound video-gamey to you, then you'll love this one: pieces of the ground fall away into a chasm once stepped on.
- Hazards from above. Falling rocks, lightning strikes, hails of arrows, etc. Since you can't just draw these on the battlefield like you can with floor hazards, it's better to telegraph them one turn ahead of time.
- Massive or growing hazards. Rough weather and storms, an earthquake, a growing fire, rising water, decreasing oxygen, etc.
- Obscurity. Darkness is the big one, as is fog. Pockets of sunlight that poke through in rooms with darkness can be an interesting addition, since it allows PCs a space to fight without a torch in their hand, or maybe a "trap" to shove a sunlight-sensitive dark elf or troglodyte into. An environment that's extremely hard to hear can also be used to justify some disadvantaged perception and opportunities to use stealth even out in the open.
- Dynamic thresholds. There are several exits to the room, there's a chokepoint, there are staircases, narrows spaces/squeezes, etc.
- Traps. Better to use ones that are visible since PCs can't take the time to prudently search for traps during the heat of battle. Just have them out in the open and force PCs to move around them or get shoved in by monsters.
- Generally interactable scenery. E.g. you're fighting in a kitchen and it has tons of kitchen equipment everywhere. All it takes is for you to name 2 or 3 objects in every battlefield: chandelier, fire pit, array of glass bottles, etc. Bonus points for destructible scenery, such as pillars that can be knocked over.
- Cover. This is a huge one and should feature in some capacity in nearly every battlefield you use. I don't care what rules you use for cover, you can decide mechanics yourself and research some options you like. But include barrels and crates, pillars and trees, big broken objects like carts, some corners to hide behind, a portcullis, a low wall, whatever.
- Creature positioning. Maybe the monster is tethered to a spot like a dog on their chain. Maybe a PC is tethered to a spot. Maybe something physically separates the PCs from one another. Maybe there's a large distance between the PCs and the monsters at the outset of the battle, like if the PCs start getting shot at by archers across a chasm. Maybe the monsters use battlefield formations like infantry walls, clusters, a perimeter around the PCs, etc.
- Shifting elements. Moving platforms, big rotating gears, changing walls/ceilings/floors, pockets of anti-gravity (or maybe the whole battlefield has anti-gravity that turns on and off), etc. Don't forget wild magic zones.
- Water. Puddles, rivers, waterfalls, sewage, drains, boats atop a big body of water, or even just a whole battle submerged in water.
- Monster has lair actions. If you aren't playing 5E then you should steal some of these from it, they're one of the best parts of the whole system.
Oh my lord I could keep going and going and going and going. Another handy list is one I included in the "Dungeon Resources" page of my RPG Brave (link to the main page for that here, where you'll find the PDF). It's a table of architectural room types like "mezzanine" and "stairwell" so that, even if there aren't any of these neat interactable elements, the shape of the room itself opens opportunities for interesting gameplay (not to mention, seems more believable as a real architectural space).
This is the one that I honestly think is possibly the most valuable and the least frequently used. The number one flaw is that, too often, the only goal in combat is simply "kill everyone on the other side." For most of my life that I've been running games, that has made up a small minority of all the combats I've run. There are so many other possible goals. And even if the goal is just "kill everyone else," then there are also many constraints and complications that can affect the situation in interesting ways.
- Enemy must be dealt with within a time limit
- Enemy must be distracted until a certain point in time
- PCs simply must survive until a certain point in time
- PCs must defend innocents/object/location
- PCs must rescue hostages
- PCs must get from point A to point B (can include escaping)
- Race against the enemies to a target
- PCs must steal an object (while being attacked)
- PCs must complete a ritual (while being attacked)
- PCs must kill one specific target
- Enemies won’t stop spawning until puzzle is solved/object is destroyed
- PCs must capture target(s) alive
- Enemies are trying to capture PC(s)
- PCs must acquire information
- PCs must deescalate the tension
- Enemies ambush PCs
- PCs have a chance to ambush enemies
- Specific PCs are being targetted
- Fighting multiple factions simultaneously
- PCs are disarmed
- Magic is either unavailable or useless
- Only magic is allowed
- PCs are exhausted (don't use the 5E exhaustion rules. They suck. Pick something better from another system)
- There will be legal consequences for certain actions taken in combat
- Allies are present/coming
- Enemies are illogical
- Don't forget to have the enemies surrender or retreat! 90% of my combats end this way!
- Dialogue during/before/after a fight. Monsters who threaten PCs, lie to them, try to persuade them to give up, or try to convince them this is all a misunderstanding
- Any of these conditions change mid-battle
In summary, in your next 5 combat encounters, try to include at least one item from each list. Don't overdo it, but don't just roll randomly either. Read through them and pick the ones that seem spiciest to you, or at least complementary to some monsters you're about to use. After that, if you're still unsatisfied, then go ahead and begin exploring some other rules for combat from systems other than the one you're playing. There's a lot of really amazing stuff out there for you to plunder and I encourage you to do so, but first I just want to make sure the problem has been diagnosed correctly.
Bonus content: here's Patrick Stuart's theory of Game/Threat Polarity.