I can definitely understand the struggle with making a climactic encounter difficult enough without being overwhelming to run as the DM. Sure, you could throw in MORE enemies, but that just gives you more minions for which you have to track damage, take turns, etc, and in the end I find that my X minions are destroyed in the fireball whether there's 5, or 10.
So let's look at other ways to add to an encounter to increase a sense of epicness. What if the dungeon was caving in/collapsing, and in about 5 minutes the whole place is going to be rubble?! What if the goblin shaman who's running the keep is on the other side of a long bridge, which is protected by some dubious-sized SWINGING AXES?
Something that I'd like to see change is the big thick line we draw between monster encounters and skill challenges, puzzles, and traps. So many DMs knowingly, or unknowingly, draw this thick heavy line that separates one half of the game from the other. And what do you end up with? Well, you get two halves of decent mechanics. I guarantee you can get better results if you combine the two, provided you do it well. I'm not talking the "take a roll of duct tape" kind of join, more of a "mixing blue and yellow play dough together to make GREEN". Get something different out of your encounters. It'll make them more fun to run, and your players will find it more fun to play.
So, the million dollar question: how do I add traps and hazards to an encounter to make it better?
Notice the emphasis on "make it better". Don't just slap one trap or hazard in each combat-encounter room and clock out. You want to add something to the encounter, but you're looking for improvement. If you mix every colour of paint together you lose colour entirely. Look at what you have and ensure that your trap or hazard is a worthy inclusion in these situations.
Things to ensure
1) Make sure the hazard or trap suits the environment and enemies they are with
Flame-pit traps are awkwardly out of place in an ice-dragons lair. An ogre's cave would feel weird if there were repeater-crossbow traps around the place. A dwarven stronghold that has been well maintained would probably not be riddled with "crumbling wall" hazards. Try to make sure that traps and hazards aren't too jarring when you include them.
2) Make sure the trap isn't counterproductive
This also goes with the first one in a way, make sure that the trap isn't a massive inconvenience for the monsters too. A room of poisonous gas would be as dangerous to goblins as it would to the PCs (if not MORE dangerous!). Instead, imagine a poisonous gas room in an undead dungeon, or a yuan-ti lair.
For best effect, put in traps that only inconvenience the PCs, and not the other monsters which they would be fighting. A "closing wall" trap is unbelievably nasty when you are fighting wraiths which can freely move in and out of the room. Spiky pit traps are extremely dangerous when you are fighting a floating beholder in his throne room. While fighting 3ft kobolds, the room may be littered with pressure plates that activate dart-firing traps from the walls.... But these traps are built 5 feet off the ground, so that the kobolds are immune to the danger!
3) Make sure the trap is meaningful (and not just shrugged at, easily avoided, etc etc)
What good is putting a fancy "blades scything out of the walls" trap if the party can just walk up the middle for the whole encounter? Is there really any point in putting a giant pit trap on the left side of the room if the fighting is going to take place on the right? Don't throw in traps and hazards for the sake of... throwing in traps and hazards. Make sure that the traps play SOME role in your encounter, by either influencing the PC's decision to take longer routes to the enemies, or by changing how and where the combat is going on.
4) Give the characters a reason to interact with the trap or hazard
I really cannot stress this point enough. If you want your trap to be a "here's an obstacle!" Then the players will essentially treat it as if it was just that, an obstacle. They will go around it/find another way. In which case, you should've just used a stone wall and saved yourself the prep time of choosing and injecting the trap/hazard in this encounter.
Traps and Hazards should have the option of risk vs. reward. Sure, there is a short, narrow bridge over water, but swimming across the distance (or attempting to jump over) is always another option. If you want to spice things up a bit, used poisoned water, or acid, or lava.
Traps have a trigger, and traps should have a way to disable/mitigate. Some traps can also be used by the players to affect the enemy! Lever-activated traps (like stairs-to-ramp traps, toppling bridges, even potentially pit traps or kissing maiden traps) can be a fun way for characters to enact revenge on the monsters with a taste of their own medicine.
Also, with regards to disabling/disarming traps, that's what rogues are good for! Many think of rogues as the kill-stealing dagger dynamos who hide out of harm's way until it's time to deal a bunch of damage to an enemy...followed by them hiding again after their attack. NO. They are also great at disarming traps (Artificers and Bards are also decent at this). Perhaps the rogue has to sneak/dash past the trap and then hastily disable it while the ranger/wizard provides covering fire. Once the trap is disabled, the fighters can now charge through the corridor of death, safely, and help the rogue survive against the enemy minions.
5) Make sure the trap is not impossible to overcome
There is no point putting in a trap that auto-kills. A trap that blocks a path and has no way through (without obvious death) and no way to disable, again, functions as a stone wall. Note that when I say auto-kills, I mean in the context of "there's no way of going through this corridor without dying." Perhaps an extremely deadly trap would "auto-kill" a player, if successful, but there has to be a way for the party to get past the trap. It's the same as pitting the PCs in a combat against a foe that's impossible to beat. Where's the fun in that?
Example Scenario, Eberk the Terrible
The Party have slogged through Eberk's wizard tower for hours, and have finally reached the top level. Here is the climax of the area - the final battle of the player characters vs Eberk the Terrible. But, he is not alone.
· Sprite (Eberk's familiar)
· Two Shield Guardians
Traps and Hazards
· Wall of Force - Two levers in the room must both be pulled down in order to disable the wall (pulling both levers back up again will re-cast the wall too)
· Electric-warded floor, two 10ft by 10ft areas, one near each lever. If someone stands on it, they take 8d6 Lightning damage (DC:15 con save halves damage). This trap counts can be mitigated with "dispel magic" as if it was a level 3 spell.
· Swinging Axes Trap - One other lever in the room can be pulled down to activate a dozen, giant, SWINGING AXES to come into the room. After 6 seconds, the lever returns to the upwards position, ready for another pull. A player in the path of a swinging axe must make a DC15 Dex save or take 6d6 slashing damage and be knocked prone.
Eberk sets up in the middle of the room against the far wall. The swinging axe trap lever is behind him. He is surrounded by the wall of force. Outside the wall is his familiar, and his shield guardians, as well as the two levers that activate or deactivate the wall.
In combat, Eberk will cast spells from his familiar's position while staying in the safety of the wall of force. If a PC teleports inside the wall of force, Eberk will attempt to banish them. If the wall goes down (from the two levers being pulled), Eberk will pull the "Swinging Axe" lever behind him, and then cast blink so that he leaves the area while the swinging axes scythe through the room.
This just one example of some ways that you can include traps and hazards in your combat encounters to make them feel a bit more epic. They are traps that are interactive, have a purpose to exist, and provide alternate strategy options for the players to overcome their enemies here.
Here is a quickfire list of my favourite traps or hazards to get your ideas spurring
My quickfire list of favourite traps
· Pit Trap
· Kissing Maiden
· Closing wall trap
· Bucket-over-the-door trap
· Bear/Hunting trap
· Lava/water flowing into the room trap
· Darts from the wall trap
· SWINGING AXES
· Scythe-blade wall trap
· Falling Portcullis trap
My quickfire list of favourite hazards
· Poisonous Cloud in area
· Cloudkill in area
· Lava or Acid Pit
· Campfire/ Open Fireplace
· Open Graves
· Crumbling Walls
· Caving-in Roof
· Spiked Palisades
· Cauldron of Acid or Lava
Peter is an avid dungeon master, role-player, and story teller. When he's not running homebrew campaigns, he is creating new worlds, or he is reading and writing fantasy stories, forever immersing himself in the gaping black-hole known as the fantasy genre.