Okay, so you’re writing up a monster entry. Run through this checklist to make sure that you haven’t missed anything.
#1. The concept should be unique, compelling, and communicable.
You probably have a lot of concepts in your head, but which ones make for good monsters?
You want something that is different from what your players have already encountered (unique), you want it to be cool enough to hold their attention (compelling), and you want it to be something that you can describe (communicable).
Like, a lot of Lovecraftian monster concepts will fulfill the first two requirements, but if you can’t describe how it looks and fights, it’ll just be a blob of hit points to your players. (Minis assist with, but don’t negate, this requirement.)
It may also be worthwhile to think about the monster will be described by you at the table (and by other DMs). The best monsters are the ones that can be conceptualized in a single sentence, even though you can spend additional sentences embroidering it.
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| Lub Glubs from Adventure Time (They look like drifting pool floaties until they get close.) |
#2. The monster must be fun to fight.
We’re talking about monsters, so combat is likely to be involved. Your monster must be fun to fight. This comes from (2a) abilities, but also (2b) tactics, (2c) environment, and (2d) weaknesses. Each of these is worth a fuller discussion, so I’ll talk about them in their own sections below.
So let’s return to talking about the things that make combat fun. Abilities, tactics, environment, and weaknesses.
#2a: Abilities should be appropriate, novel, and dynamic.
By ‘appropriate’, I just mean that the mechanical representation should match the fiction. At a basic level, fire breath should do fire damage, but does a ghost hammer deal bludgeoning or force damage? What’s the best way to handle a lich that drains your life? Level drain, Con damage, reducing max HP, exhaustion, or reducing hit dice?
You have a lot of leeway here, so get creative. Players appreciate when a mechanic is especially cutely appropriate, but it’s not a requirement.
By ‘novel’ I mean that you should try to give them something that they haven’t seen before. If you’re writing an adventure, you need to make sure that there is good differentiation between your concepts. (If you’re writing a monster manual, you can have some similar monsters, because it’s not like the DM is going to make the players fight all 7 dragon varieties in a row.)
And by ‘dynamic’, I just mean that the abilities should push players into interesting decisions. Fire breath is cool and threatening, but it’s not dynamic. The players just take the damage and keep on trucking–there’s no choices to make. Wall of Fire is more dynamic, because now the party is split and they have to make interesting choices about whether or not to jump through the wall of fire, or wait for it to dissipate.
#2b: Tactics should also be appropriate, novel, and dynamic.
You don’t need cool abilities to have a cool encounter. I wrote a post about how tactics can make for fun differentiation between mechanically identical monsters. I won’t rehash it here, except to say that different monsters in your dungeon should have different motivations for opposing you (food? defense?), different roles within combat (hit and run? blind aggression?), different combat goals (eat you? rob you? escape?), and different levels of commitment to combat (morale).
Simple things like modes of movement and attack can also suggest interesting tactics. For example, a flying skeleton archer doesn’t need any special abilities, because you already know that the players will have to come up with new tactics to defeat them (compared to fighting regular skeletons).
#2c: Environment should also be appropriate, dynamic, and/or interactive.
You could argue that this belongs in the adventure design section instead of the monster design section, but the two are interrelated. Combat should never take place in a featureless white room, and certain monsters are more likely to be found in certain locations.
The environment for flying skeleton archers might be a lonely clifftop where sky burials were practiced. Or it might be an ancient bridge where the bird cult threw sacrifices off. Or it might be deep in the catacombs, with bone “nests” built high up on the walls.
Interactivity comes from hazards and difficult terrain, but it also comes from advantages. Cover, chokepoints, hiding places. Also explore verticality: stairs, levels, half-levels, ladders, pits, steep slopes (“scrambles”) and pools.
Also consider how the environment affects an encounter. A low roof makes a flying skeleton archer much easier to defeat. Conversely, if the room has a high ceiling and is bisected by a pit, flying skeleton archers are much more threatening.
#2d: Every monster needs weaknesses (either implied or explicit).
If none of the monsters have any weaknesses, the players will use the same offensive tactics to kill them every time. This can be implicit, like how a flying enemy is “weak” to ranged attacks and nets, or how a stupid enemy can be baited into a trap.
Or a weakness can be explicit, like scarecrows being weak to fire. I’m not a big fan of hard lock weaknesses that require a specific material or spell. “Immune to damage from non-silver weapons” or “Possession can only be ended by casting protection from evil”. If the party has a silver dagger there’s no interesting decision to make–you just use the dagger. And if the party doesn’t have a silver dagger, they just run away and there is again no interesting choice to make. (Hard locks like this can sometimes be useful as metroidvania-style keys, where a certain monster is impassible until the party can come back with silver weapons, but that’s still a weaker use case, in my book.)
I prefer soft lock weaknesses. “This enemy takes double damage from silver weapons” or “possession can be ended by protection from evil, holy water, or unconsciousness”.
Best are versatile weaknesses, that allow players the most flexibility in how they are approached. “This monster’s brain is exposed, and it takes triple damage when attacked from above” or “100% food motivated” or “scared of loud noises” or “killed by falls”. However, you’re a little more limited in these, since you have to use options that all parties have access to, so you shouldn’t only use versatile weaknesses–you should have some soft lock weaknesses in there, too.
Also remember that weaknesses can take the form of buffs to the party. A flying monster with a ranged attack is pretty threatening but if it gives everyone within 50’ the ability to fly, it provokes a new set of tactics and risks. Similarly a monster that is blind and has a terrible sense of smell allows for players to effectively “turn invisible” when they’re fighting it, which also allows for new and interesting tactics.
#2e: Consider threats besides "it kills you". Consider solutions besides "you kill it".
Murder is a common language in tabletop. A fight to the death is instantly interesting, and it is a common focus of game mechanics. But please, step outside of that box.
I talked about alternative types of threats up in #5, but also consider that the players might "win" the combat through other victory conditions:
- Prevent the monsters from fleeing and raising the alarm.
- Avoid breaking the priceless vases in this room while the monsters try to kill you.
- The monster is a sage. Every round, you can ask a question that the left head will answer truthfully. Meanwhile the right head (and the rest of the monster) is trying to kill you. Stay alive and think of good questions.
- The monster is treasure, but only if you kill it in a specific way.
- This monster can only be killed by silver (or salt, or fire, or song, or whatever).
- The monster cannot be killed while it is in contact with the earth.
- This monster can only be drowned.
- This monster will only die if it is physical removed from its tomb.
- This monster cannot be harmed by anything crafted by the hands of men.
#3. The monster should support interesting dungeoncrawling.
If you haven’t played an OSR game, you might be used to having combat start once the players walk into the room. But there’s a huge potential for interesting (hostile or non-hostile) interactions to occur before initiative is rolled.
This includes things like roleplaying and faction play. But it also includes things like:
Bone needle men prevent all rest in a dungeon. The party could hunt them down and silence their rattling skulls.
Goblins have tiny crawl tunnels they use to move between rooms. The party could block them off, or strip off their armor and crawl through themselves.
Through the keyhole, you can see an owlbear sleeping. Ferocious, but known to be easily distracted by a large enough piece of meat.
This is where you can get really creative, and where the most interesting OSR-style problems can be inserted. However, these sorts of things are usually buried in the monster write up. The rattling of the bone needle men is probably obvious to a reader since it’s listed under monster abilities. But the crawl tunnels of goblins might only get a brief mention under the Ecology section, where it’s easily missed. And while the monster entry might mention the rapacious hungers of owlbears, that type of interesting situation is often missed by the monster manual, and left for the people who write adventures. (Which is a pity.)
This one is probably the hardest to address, since it doesn’t map well to any of the normal sections of a monster entry. Still, you should give it some thought. A monster has the potential to be a lot more than a stack of hit points and abilities.
Some places where a monster could interfere with dungeoncrawling:
- It's a member of a larger faction.
- It blocks off part of the dungeon. Optional: it's probably big enough to TPK the party. Optional: it has a weakness, discovered elsewhere in the dungeon. (Basically just a lock and key.)
- Literal lock and key: once it is killed (or appeased) a new path unlocks. The water level falls. The necropolis opens.
- It interferes with a resource:
- Light
- Rest (e.g. no resting or eating lunch)
- Healing (e.g. all healing is halved)
- Magic
- Loot (e.g. the treasure is cursed until you kill the mummy)
- Senses (e.g. no noise is possible in the Halls of Silence)
- It burrows between the rooms, creating new tunnels.
- It has an easy line of communication and/or observation, and can speak to the party as they navigate the dungeon. It may want to scare them away, want the party to release it, etc.
- It can generate illusions.
- Curse of the Dao: all fall damage is doubled. (And the monsters know this.)
#4. The monster should fit into the world.
The monster needs to fit into the world in a way that makes sense. This usually gets glossed over–if you are designing another undead then everyone already knows that it was created by a necromancer, or arose spontaneously from some sort of restless spirit. If it's alive, you should spend a second to think about where it eats, sleeps, and hunts.
But maybe your design is something more novel. Your monster is the angry anti-ghost of the unborn. Or maybe something that is too specific for the DM to just drop it in the dungeon without an explanation, like a squad of humans who fight with grenades. In those cases, you need to spend some time explaining the context for this monster.
It’s tricky because you may be torn between providing a specific explanation (“These are Malthusian grenadiers, servants of Witch Mountain.”) or a general one (“Grenadiers are commonly employed by mercenary forces.”) Because we want our written words to sound authoritative, we often just pick one–but of course there’s nothing stopping you from giving 2 or 3 contexts that your monster might exist within the game world.
Also, consider giving your monster actionable connections to the world. A mated pair of owlbears should imply valuable babies nearby. The presence of the dandelion knight is proof of an alliance with the fairy princes (so the party should be extra wary of them). This vampire has the sword of St. Vipera--is this the Saint herself?
Even something small like a group of orcs, where one incongruent orc is wearing a brand new set of armor, raises interesting questions (and connections) with a single detail.
#5 - The monster should be threatening.
Sure, your monster has attack rolls and it deals damage. It certainly poses a threat to HP totals.
Attacking HP is the oldest and most comfortable way to threaten the players. It’s also the one that is always approved by the implied social contract of the table. (Players don’t object if they take 17 points of damage. But depending on the game, they might object if their sword gets rusted away since it feels unfair.)
The mnemonic for this is “attack all parts of the character sheet”. Abilities scores are usually fair game. Inventory is usually a possible target, too, except in very protective 5e games. XP/Level Drain is an option, but can be deployed with care. Character abilities and skills are usually off-limits, but you can still tamper with them in ways that are fun. In 5e you can have monster abilities that attack inspiration, hit dice healing, proficiency, ideals, etc.
But also remember that you can attack the out-of-combat resources, too. Time is a big one. Noise can attract wandering monsters. A monster like a carbuncle might have a valuable gem on its back that goes down in value after each round of combat. Killing these (murderous, frenzied) dwarves might ruin your reputation with the (friendly, chill) dwarves in the next cave.
Threat is one of the biggest ways that a monster can engage your players, so think about it carefully.
#6. The monster should surprise.
I’ve touched on this before, but you want your encounter to be dynamic. It should force the players to change their plans a little bit.
Ideally, you want to push the players into at least three interesting decisions.
A simple example of this might be:
There’s a giant golem in the next room. How do we kill it and/or get past it?
The giant golem is being controlled by little dudes inside of it. How do we kill the little dudes inside this big dude? Can we make a smoke bomb? Can someone fit inside?
One of the little dudes is running for help. Should we chase him down? Who will go?
Without any surprises, the party will use the same stale tactics.
#7. The monster should reward.
XP is a boring reward. Literally the worst.
Getting past the monster is often a sufficient reward on its own, if there is more cool dungeon to explore.
But also think about the other possible rewards that the players could get out of this encounter, and perhaps include some.
A new ally.
Information.
Delicious monster parts to eat.
Useful weapons and tools.
Valuable gold or monster eggs.
Weird consumables like potions and acid sacs.
A new shortcut in the dungeon.
