Thoughts on Building Encounters

If you’re a dungeon master, you have a choice of running your players through published adventures such as Storm King’s Thunder, Curse of Strahd and the Tyranny of Dragons duology, or writing your own material from scratch. I’ve usually taken the latter approach, although with my current players—a group of mostly newcomers to Dungeons and Dragons—I’ve opted for a mix, starting them off with The Lost Mine of Phandelver, then a homebrew quickie, then Tyranny of Dragons peppered with personal sidequests.

Published adventures often give little or no guidance on how monsters—especially ones in random encounters—ought to behave, and occasionally, what guidance they give is inconsistent with what would be optimal, given a monster’s abilities and features. So a large part of my motivation behind writing this blog has been to provide that guidance, so that other DMs don’t have to figure it out on the fly, potentially resulting in lackluster encounters.

But when you’re writing your own material, you have all kinds of freedom. You decide what environments the player characters will travel through. You decide what villains they’ll fight, what those villains’ plans are and what kind of minions those villains will have. You decide what kind of help and hindrances the PCs will encounter along the way. And here’s a point of underrated importance: You draw the maps.

If you’ve studied sociology, criminology or urban planning, you’re probably familiar with Oscar Newman’s theory of defensible space. If not, here it is in a nutshell: People not only feel safer but are safer when they have a strong emotional investment in defending their home territory; when they can easily see what’s going on in that territory; when the environment includes visible signifiers of security, such as gates; when there are places for people to assemble; and when adjoining areas are also safe.

Newman was thinking primarily in terms of the safety and security of law-abiding residents, but criminals can exploit defensible space principles, too. Ever seen the movie Training Day? The scene in which the officers drive into the public housing cul-de-sac dominated by gangsters provides a nail-biting example. There’s only one way in and out, and no place for a trespasser to hide from the eyes of the residents.

A medieval castle is about the most literal example of defensible space you can imagine: walls, gates, moats and drawbridges, battlements, barbicans, watchtowers, and the wards and baileys where guards mustered and trained, all serving the explicit purpose of defending those inside from outside attack. But the defensibility of a castle didn’t come just from its design; it also came from its location. A castle might be sited on a river, on a rocky outcrop or in a mountain pass, in order to limit the directions from which attackers could approach.

The fifth-edition Dungeon Master’s Guide gives DMs good mathematical tools for constructing a combat encounter pitched to a desired level of difficulty. But it also includes a pair of sections that are easy to overlook: “Modifying Encounter Difficulty” and “Fun Combat Encounters” (pages 84–85). They’re short, so I’ll let you look up what they say for yourself. The key takeaway is, if you’re simply throwing your PCs and monsters at each other in a plain, rectangular room, you’re missing all kinds of opportunities to add flavor and complexity.

There’s one part of Volo’s Guide to Monsters that particularly delights me: the section on kobold lairs. In my post on kobold tactics, I make three points that are essential to understanding how kobolds fight: First, by necessity, they fight in darkness or underground, not under broad daylight. Second, they’re small and weak yet instinctively coordinated, so they seek strength in numbers. Third, they make use of traps. Volo’s takes all these points and runs with them, depicting a kobold lair as an anthill of twisty subterranean passages, full of traps and choke points, in which larger creatures will get lost, stuck or both. This is defensible space, distilled. But not just distilled—customized to maximize kobolds’ comparative advantage over their likely foes. The foes are big, and kobolds are small; therefore, the passages are small. The foes may not be able to see in the dark, and the kobolds can; therefore, the passages are unlit. The terrain is familiar to the kobolds, unfamiliar to their foes; therefore, the passages are full of traps to punish the unwary and ignorant.

In the campaign I’m running now, the home village of our hill dwarf ranger is under attack by suspiciously well organized goblin raiders. Tracking the goblins, the party has found that these goblins are being coordinated and commanded by hobgoblins, who’ve fortified a cave in the karst foothills of the Spine of the World. This cave is their defensible space. They’ve built up earthworks around it and constructed watch platforms. Inside the cave (our druid discovered, reconnoitering in the form of a fly), they’re building mangonels and making incendiary projectiles out of birch stumps and pine resin, which they plan to launch against the shake–roofed dwarven village.

In this case, though, the PCs are explicitly not supposed to attack the goblinoids in the cave. There are too many of them, and it’s too well fortified. Instead, they’re supposed to wait for the goblinoids to come to them and fight them from the village, where they have the advantage of defensible space, in the form of a gated log palisade.

So let’s say you’re writing an adventure in which the boss monster has lair actions—an adult white dragon, for example. We’ve already established, from studying its stat block, that a dragon needs room to fly around, that it has blindsight and darkvision, that it can scramble around icy surfaces as easily as walking on the ground, and that it has a Frightful Presence that can cow those who see or hear it. We also know that it can fill certain areas with freezing fog, cause shards of ice to fall on trespassers and impale them, and create solid walls of ice, and that a dragon’s lair is filled with an obstacle course of icy walls and surrounded by miles of chilly fog.

We’ve already got a couple of elements of defensible space in place: Dragons are super-territorial, and the fog in the region around their lair disfavors trespassers. The maze of ice walls is a visible sign of the dragon’s determination to defend its lair. All we really need is a way for the dragon to see what’s going on, and that’s easy: as both a flying and climbing creature, with Ice Walk, it can either rest on a high platform with a clear view of the entrance to its lair or simply hang from the ceiling like a bat.

On top of this, what other things can we do to make a fight in the dragon’s lair especially favorable for the dragon? Maybe the lair is full of ice shelves that the dragon can leap to, so that when it’s using its breath weapon rather than making melee attacks, it doesn’t have to stand where its opponents can hit it—it can breathe down rather than across. That’s pretty good. (Or, alternatively, it could just fly to a spot on the wall or ceiling and use Ice Walk to cling there.) Also, since its lair is basically a maze, it can use its legendary action to trap PCs in certain parts of it, taking them out of commission for a combat round. And those same mazy walls can constrain the PCs’ ability to flee when it drops freezing fog on them.

OK, but that’s just the boss fight. We’ve also got to come up with some encounters on the way to the dragon’s lair. What are some of the elements we’re dealing with? The climate, for one. A white dragon is going to dwell at a high latitude and/or altitude, so adaptation to cold is helpful. The fog around the lair lightly obscures visibility, so creatures with keen hearing and/or smell will make good minions. Let’s start with those.

  • White guard drakes (CR 2) are obviously appropriate watchbeasts for a white dragon. They have resistance to cold damage and proficiency in Perception, negating the fog penalty.
  • Ice mephits (CR 1/2) would be drawn to the area around a white dragon’s lair and might even colonize the lair itself, like little elemental cockroaches. They have proficiency in Perception and Stealth, and they’re immune to cold damage.
  • Polar bears (CR 2) have Keen Smell and Perception proficiency. Need I say more?
  • Winter wolves (CR 3) have both Perception and Stealth proficiency and Keen Hearing and Smell, plus Snow Camouflage, which gives them advantage on Stealth checks in snowy terrain, giving them a decided advantage over PCs. They’re also immune to cold damage. The region around a white dragon’s lair is a perfect winter wolf hunting ground; they’d naturally migrate to such an area.
  • Yetis (CR 3), like winter wolves, have Perception proficiency, Stealth proficiency, Keen Smell and Snow Camouflage, and they’re immune to cold damage. Abominable yetis (CR 9) have all of that, plus cold breath of their own. They may be a bit much to throw at your PCs when they’re off to fight a dragon, and a white dragon might actually consider an abominable yeti an unwelcome rival that needs to be eliminated. But ordinary yetis would probably be beneath the dragon’s notice.
  • Barghests (CR 4) have resistance to cold damage, Stealth proficiency and 60 feet of blindsight.
  • Ice trolls (CR 5) appear in Rise of Tiamat. They’re just regular trolls with added immunity to cold damage. But since even regular trolls have Keen Smell, ice trolls could easily detect the PCs’ presence through the fog around the dragon lair. And unlike the abominable yeti, they’re not quite powerful enough for the white dragon to get jelly about.
  • Bheur hags (CR 7) are naturally drawn to the same climes as white dragons, they have Perception and Stealth proficiency, they’re immune to cold damage, and they share the Ice Walk feature.

I think we’ve got the makings of a pretty good monster ecosystem in the vicinity of a white dragon lair here. The mephits, especially, offer a nice recurring element that a DM can use to get under players’ skin. Malicious little opportunists, they can show up repeatedly on the fringes of fights with more powerful monsters, adding insult to injury.

Now let’s consider a villain without a connection to a supernatural lair—an efreet. Efreets are genies, which in D&D 5E are categorized as elementals, so other fiery elementals make natural minions. The most obvious choice is the salamander. The Monster Manual flavor text alludes to the enslavement of salamanders by efreets, plus they have an interesting tactic in their aptitude for disarming opponents. Fire elementals are also suitable minions for an efreet. Magma and smoke mephits can play the same opportunistic nuisance role described above, as can magmins.

That’s a good starting point, but let’s go a little deeper. Salamanders are shock attackers. Fire elementals are skirmishers. What have we got that can play the role of a front-line or long-range attacker in the service of an efreet? Not azers, because they have a history with efreets and want nothing to do with them. What about genasi? As a PC race from the Elemental Evil Player’s Companion (free PDF), they can be mapped onto any NPC archetype you like. Need a front-line fighter? Add a fire genasi knight, veteran or gladiator—or, for an elite lieutenant baddie, a blackguard or champion. Some ranged attackers? Fire genasi archers. Or, for another elite lieutenant, a fire genasi assassin.

Now you can assemble a whole unit of baddies that will pose a variety of challenges and threats to your PCs. Combine, say, 60 percent fire genasi front-liners, 30 percent salamanders and 10 percent fire genasi ranged attackers (a typical ratio of infantry, cavalry and archers in a medieval army), tuned to the level of your PCs’ party, each group employing a different set of tactics appropriate to its own strengths, and you’ve got a fight that will be just as memorable as the boss fight that follows it. (And you can also have mephits taking potshots at distracted PCs, just to make them tear their hair out.)

Efreets aren’t necessarily the best example of a boss villain, just the first one that happened to come to my mind. They’re not the best example because they don’t really have any weakness. A lesser boss is unlikely to be strong in every respect. It will have a dump stat or two, or a damage vulnerability, or such an inclination toward a specific combat role (such as front-line brute or glass-cannon spellslinger) that it’s wholly unsuited to any other.

In a case like that, a savvy boss will compensate for its own weakness by recruiting minions that are strong where the boss is weak. That glass-cannon spellcaster, for example, will surround itself with formidable brutes that can serve as its offensive line, plus skirmishers that can harass the enemy’s own ranged attackers and spellslingers. The brute boss, on the other hand, wants a couple of wingmen, and a whole lot of ranged backup, and at least one sharp-eyed controller (a cleric or bard, perhaps, or a monster with similar abilities) to notice and neutralize flank attacks.

But that’s a savvy boss. It never occurs to a stupid boss—one with both low Intelligence and low Wisdom—that it has weaknesses, let alone that it needs to compensate for them. The stupid boss knows only its own strengths, and consequently, it surrounds itself with minions that possess the same strengths—only to a lesser degree, because any minion that had those same strengths in the same degree would be a rival!

Finally, no matter who or what your main villain is or who or what its minions are, every NPC and monster the PCs encounter wants something. It has desires, it has fears, and it has animosities. It may have a sense of fairness, or not. It may feel kindness, or not. It may be loyal to its kind, or not. It may be obedient and deferential to its boss, or not. It may hold something sacred that its companions don’t, or vice versa. And it may be extra-suspicious—or extra-gullible. PCs proficient in social skills can exploit any or all of these traits if given the chance to do so.

So when you build an encounter, always have some sense of why each NPC or creature is present. What’s in it for them? What would it take for a PC to win them over to his or her side? Can an enemy be deceived, persuaded, intimidated, bribed or blackmailed into standing down or turning coat? Even beasts are susceptible to psyops if you have a ranger or a druid in your party who can Dr. Dolittle them.

See what I did there? A sophisticated approach to creating defensible space from the point of view of your main villain(s) gives your PCs something to explore for vulnerabilities. Filling out build-up encounters with a variety of villains playing different positions adds spice to combat encounters. And knowing the NPCs’ and monsters’ motivations opens opportunities for PCs proficient in social skills to swing the odds in the party’s favor. Exploration, social interaction and combat: the three pillars of D&D. Something for everyone.

Next: wood woads.

5 thoughts on “Thoughts on Building Encounters

  1. This is such a cool article. I would love to see more about different ways to implement defensible spaces with some of the other bigtime DnD Beasties. What does a Beholder Lair look like? Or even a Green Dragon?

    1. These are questions you can answer for yourself just by thinking about what these creatures’ tactics are, what they value and whom they believe they need to keep out. It’s an easy and entertaining thought experiment.

  2. Love this one. Even knowing most of it it is always helpful, and apriciated, to have it all summed up in one place. Keep up thr good work, mate. And enjoy the games.

  3. I love this one. Whenever I am building a dungeon, I go back to it, because it really does an amazing job at explaining how to maintain the suspension of disbelief.

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