Designing an Encounter - Terrain
Header Image: Wilderness (2D Fantasy Landscape) by Acidify Art
Combat doesn’t happen in an empty white room, but in crumbling ruins, sweeping prairies, tree-choked forests, sucking bogs, and cavernous tunnels. One of the easiest ways to make combat more interesting is by adding elements onto the battlefield that provide choices to the participants.
When I say more interesting, I don’t necessarily mean harder. Hard encounters can be memorable for being difficult, but that doesn’t mean they were interesting or fun to play through. An interesting encounter features choices that break free of the normal playstyle, instead of a fighter just charging forward and making their attacks, the player is given options to accomplish what they ultimately want to do. This could be creating difficult terrain that is dangerous and a single clear path that is slower but safer.
Interesting encounters include a lot more than just terrain, but we are going to start there. This is the setting for your combat, your social jabs, and however else you encounter others! Having a good setting for your encounter helps set the tension, encourages tactical play, and can help further set the mood or genre your campaign is going for.
Note: Most of what I am going to talk about here is going to be focused on combat, but that doesn’t mean that that is the only encounter that relies on terrain. Terrain can affect social and exploration encounters; a volcano is dangerous no matter if you have swords or not.
Terrain
The first part of this is to clarify what exactly terrain represents. Terrain is the physical feature that an encounter takes place on. This could be the plains, a cloud, an underground cavern, a flowing river of magma, the rocking ocean, or any other physical feature that an encounter takes place on or in. Oftentimes, the terrain is something natural though it could be artificial, like the inside of a ship or the labyrinth maze of a minotaur. Depending on what the terrain is, it can offer a host of different challenges for your players or give them new ways of experience a battle.
When creating terrain for an encounter, think about what might naturally appear there. Bursts of lightning that leap from one side of the map to the next might be a cool idea, but it wouldn’t fit inside of a tavern while it would in a broken airship crashing to the ground. A prairie could offer prickly shrubs for the rogue to hide behind, a heavy rainstorm could be flooding the city streets, or a tunnel might have gaping fissures forcing combatants to either stick to ranged attacks or risk leaping the fissures.
When creating terrain for an encounter, there are a few important things to think about.
What It Isn’t
Before we get into what terrain is, let’s first address what it isn’t and what it shouldn’t be used for. There are three things to know:
Terrain is not used for punishing specific players or removing them from the encounter. If someone can’t climb a slippery slope because the DC is impossible for them or they lack the ability to do so, that means they are unable to take part in the encounter, which is awful. Terrain is not to be used to stop players from playing the game as that sucks the fun out of playing the game and can feel like the Game Master is specifically removing someone from the game. When putting a barrier into the terrain, always have multiple ways that people can overcome that barrier, and if it requires them to use resources, even better as it gives them chances to use powers and show off how they are different from others.
Terrain should not be highly lethal and hidden. Hiding massive damage behind innocuous terrain creates gotcha moments in a game, which can create unhealthy tensions at the table. Often this is used to trick players into biting off more than they can chew by no fault of their own, creating an adversarial nature between Game Masters and players. While some tables relish that type of conflict, it should be agreed on beforehand, otherwise, the table refuses to put their trust in a Game Master. Eroding trust quickly saps the fun out of a game, creates hostilities at the table, and makes it so that players will never trust a plot hook, a piece of flavor text, or an NPC again turning your game into fights between the two sides. If you do include highly lethal terrain, it should be telegraphed. A lava flow is easy to tell it is highly lethal and has the subtlety of an ogre.
Terrain should not be ponderous. Combat takes long enough that terrain should not bog it down so much that it increases the time between turns. The fun part of any game is actually playing it and if players are sitting out for longer because the rules for your terrain cause combat to come to a standstill, then the terrain is getting in the way of the game. If you do include slogging terrain, it should be based on what the players do and something that they initiate, like sand pouring in from a ceiling is quickened by them knocking over pillars to purposefully do that.
What It Is
Just as there are things that terrain isn’t, there are things that terrain is. Understanding how to properly use terrain can create exciting encounters that are more than spamming spells and attacks.
Terrain should offer choice. Terrain should create ways for the party to make decisions that can affect the encounter and their tactics. There shouldn’t be one ‘right’ choice, as that means there is no choice at all, but rather multiple ‘right’ choices that a player can feel as if they have some say on their destiny. They might try to slog through the thick mud and difficult terrain or spend a longer time sticking to the clear path.
Terrain should have an impact. If you are going to draw it out on a map, ensure that everyone at the table knows the terrain, then it should have an impact. If it is on the sidelines, untouched, then it didn’t add anything to the encounter and just bogs down the description and your prep work. If terrain is included, it should have an impact, even if it is small.
Terrain affects everyone. If terrain only attacks or affects your player’s characters, then the terrain is an enemy. While terrain can be crafted by enemy, not every enemy should have complete control over their terrain and could be put flat-footed when dealing with the terrain just as much as your player’s characters are. Then again, the terrain doesn’t have to affect all creatures in the same way. A lava flow doesn’t affect an efreeti the same way it does a human.
Examples of Terrain
Terrain can come up in any encounter you want to be more interesting than a blank room. It can be simple, like populating different sized trees across a forest encounter with thick shrubs creating difficult terrain, or complicated, like having a multistage terrain feature that slowly gets bigger during the encounter. A few examples are provided below with various effects based on the terrain.
Artic
Thick snow patches slow down movement, but a character could spend an action and move up to half their movement speed to clear out a path for their party to follow.
Slippery slopes coated in ice force creatures to make an acrobatics check to keep from falling. Those who fail suddenly begin sliding down the ice slopes up to 1d4 x 10 feet before striking a rock or ledge to arrest their fall.
Thunderous noise, like from spells, threatens to cause an avalanche while in mountainous regions that is 1d10 x 100 feet across and will arrive in 2d4 rounds.
It is far easier to be tracked, and to track, while in the snow.
Thick blizzards change visibility each turn. At the start of a creatures turn, they roll 1d6 x 5 to determine how many feet they can see in front of them.
Deserts
Sand is constantly shifting along the dunes, requiring an athletics check to move at full speed up them, otherwise, it is treated as difficult terrain.
A sandstorm reduces visibility to 1d6 x 5 feet and all creatures within the storm take bludgeoning damage unless they have taken cover.
Electricity builds up within the sand, discharging on those who use lightning spells, though it may even empower the spells.
Forests
Massive trees grow with tiny trees growing around them, creating difficult places to move. Random placements of trees could create a nice copse of trees for cover, or make it almost impossible to engage the enemy in melee without spending a turn or two to move around them.
Shrubs create natural difficult terrain, with some even having thick briars that cut and stab into any creature that tries to barrel through it. A creature can treat briars as difficult terrain, and not take any damage, or charge through it at normal movement and take 1d4 piercing damage per 5 feet.
Thick canopies block much of the sunlight, plunging the forest floor into dim light or even darkness during the middle of the day.
Thunderous spells cause trees to collapse. Roll a d8 to determine what direction a tree falls and 2d20 to determine the height of the tree. A creature must make a Dexterity saving throw or become restrained under the fallen tree.
Shrubs are quick to be caught on fire from fire spells. Fire spreads among the brush in a random direction every turn, roll a d8 to determine the direction.
Hills & Mountains
Wide fissures require creatures either to jump across or to climb down and then climb back up.
Massive boulders litter the ground, offering ample places to take cover or as ammunition for spells and giants.
Thin ledges offer the only places to cross, requiring an acrobatics check to stick to them. Failure causes one to fall 1d10 x 5 feet until you hit a ledge below.
Steep hillsides and mountain slopes make it easy to move down them, for every 10 feet you move down, it only takes 5 feet of movement. Going up the sides requires 15 feet of movement for every 5 feet moved up.
Plains
Grass readily catches fire from fire spells, burning in patches that spreads quickly. Every round, roll 1d8 to determine what direction the fire moves.
Grass grows almost 5 feet tall, allowing small creatures to hide in the tall foliage.
Prone creatures are covered completely by the foliage, making them heavily obscured from creatures more than 5 feet away.
Strong winds make any ranged attacks outside their first range increment to automatically miss.
Swamps & Marshes
Thick bogs can be much deeper than they appear. Bogs are 1d4 x 5 feet deep.
Bog gas ignites easier, empowering fire spells. Treat all 1s rolled for damage as 2s.
A long, clear path zig zags through the bog, making it a slow process to make it to the enemies without cutting through the bog.
Creatures within the bog waters are heavily obscured thanks to the murky waters.
Sunken trees make small bridges from plots of land, requiring an acrobatics check to navigate without falling into the swamp.
Artificial Terrain
A crashing skyship has corridors bursting into fire and lightning.
Temples have long bench seating, creating difficult terrain unless one follows the corridors between the benches.
Ships rock back and forth on the ocean, requiring an acrobatics check to remain on your feet every round or fall prone.
Wizard tower’s stairs are in constant motion, some stairways rotate while others have stairs that flow backward or go completely smooth.
Castles have hidden murder holes in their walls, with small holes just large enough for guards to shoot arrows out of them and into the hallways.
Weather
Heavy rainfall reduces visibility to 1d6 x 5 feet.
Heavy winds cause ranged attacks exceeding their first range increment to miss.
Extreme temperatures empower fire and cold spells, treat all 1s rolled for damage as 2s.
Climbing while it is raining makes it harder, imposing disadvantage on athletic checks.
Flooding can knock a creature over, at the start of their turns, creatures must make an athletics or acrobatics check to remain on their feet or be knocked prone and pushed 1d4 x 5 feet.
Want More?
If you like this topic, consider checking out my various other posts on exploration and the Wilds! I’ve written about how to Survive the Wilds, tips on how to Explore the Wilds, a system for Exploration, tips for Running a Game in the Dark, more tips on making exciting encounters, and even a fun minigame to represent hunting!
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