The dungeon boss is a quintessential part of the RPG experience, from the retro days of Final Fantasy and Encountering Garland to the blood pumping action of the Dark Souls series, the grand evil monster in its lair should feel suitably gratifying to exterminate. However, when party could consist of three or more characters, that is where lair and legendary actions come into play, adding some much-needed intensity to a regularly dull singular monster’s turn.
Lair actions are a simple way to keep up the pace of the action economy, ordinarily happening on a set initiative such as ten or twenty. The effect often happens independently of the combative creature, or creatures, almost creating a sense of dread as the players have to contend with the very room around them. For larger groups fighting a singular boss do not be afraid to add a second lair action per round at a lower initiative, thus providing dynamic change players weren’t anticipating. So, with the preface out of the way let us delve into the homes of the monsters.
Low-Level Players(Levels 1-5)
The Kobold Mound- Detracting from the mundane form of a single boss, why not try a horde of monsters hidden under the ground, waiting to be freed? Kobolds are a staple of D&D as they offer a plethora of fun and unique ways to approach combat akin to a horde of miniature mad scientists, that aren’t very smart. Taking from the early days of Warcraft and flavoring the orc defensive huts to our needs, the small creatures burrow slightly under the ground and pile up dirt creating protective mounds. They can then attack with their spears through small openings, stabbing blindly. Making sure to litter mounds throughout the battlefield, perhaps luring the party here for a trap, have any player within 5 feet of the pile make a dexterity save or have their ankles impaled. This is a destructible lair as well, allow the players to target the mounds, which have a relatively low AC and health, and then have 1d4 kobolds spring out and join the fray upon its destruction, the overkill damage of their home’s destruction being split amongst the Kobolds.
Grasping Hands of the Damned-Offering a bit of a terrain hazard the grasping hands can be any limb, perhaps a mass grave or pile of corpses lay amongst a fiendish undead’s lair. A favorite of intelligent undead from Wights to the mighty Lich no body should go to waste, as even severed limbs and skulls have their uses. The undead entity’s very essence permeates this abode, on the Lair Initiative have all corpses, pieces of corpses, walls and floors made of corpses, pretty much any undead architecture reach out and grasp for the players. A strength or DEX save here, as the creatures attempt to restrain the player. Upon failure, the player should take some damage if at a higher level and be restrained until they can break free as an action, thus repeating the save. This is a fun one if, after activating the action, the DM moves the corpses around 5-10ft per round, creating a constant hazard for the players. If going with the “Let’s decorate the dungeon in bodies” route, then have it provide rough terrain or even some sort of cover.
Mid-level Players (Levels 6-10)
Facing down ogres, evil magi, and unfriendly drow the characters who have reached this middle tier of adventurer should be proud to take on dangerous threats while delving deadly dungeons. Medium-sized parties should be facing down their first dragon around now and as such, it is time to provide them with a feeling of deadly effectiveness.
Lightning Tether-Pesky wizards fading to the back and chucking fireballs from far away? Is the fighter about to action surge your BBEG and you need to dunk them in a pit? Well, fear not as the “Lightning Tether” is here! A favorite of the psychotic professor, this action pairs well in a steampunk or arcanist’s lair. By strategically placing various enchanted metal lightning rods around the arena, making sure to keep tight sightlines so players are enticed to approach them. Once they think they are running upon the enemy, oh no its time to shoot a lasso of lightning(or force or whatever your preference to snatch unsuspecting players) right around their tiny, trembling torso. Allowing for a moderate dexterity, or constitution for a thunderous knockback effect, any player within 20 feet who fails should take a bit of damage and have them moved either toward or away, from the pillar. It may be fun to put this next to the edge of something for some added falling fun!
High-level Players(Levels 11-16)
Moving on up, the creatures a party of adventurers who have made it to this level would encounter should be a force of nature. No longer do wandering orc tribes bother this group, no they are storming the citadel while riding a pegasus and carpet bombing the army below.
Endless whispers-This one works well for the encounter that doesn’t have any spells in their arsenal. Silence is quite an effective spell, as it can shut down a magical player’s whole plan of attack. Calling upon screaming and tormented souls from the abyss this is a favorite for only the most depraved of fiends. As the ancient noise penetrates every corner of the room, have a CON save on the start of each turn as this effect goes on. On a failure have the player either walk into a hazard or attach an ally, pretty much whatever dark twisted things your mind can think of. This is also an effective method for breaking concentration on targets that are trying their darndest to focus on that fourth level witch bolt, as they become unnerved and fail the con save, dropping the spell. Just beware, if you choose to take the optional dropping of spells, your warcasters may rebel.
These characters and players have proven themselves, as they are legends in their own right for sticking to a campaign this long. As these adventurers have saved or subdued kingdoms and looted the ancient dragon’s horde, it is time to kick it into gear and aim to change the very battlefield beneath their hardened feet.
Rain of the Abyss-What happens when you mix meteor swarm with the works of H.P. Lovecraft? That’s right, Cthulu eggs falling from the sky! As inky black balls of rock with lashing purple tentacles descend from the heavens its time for a DEX save, or they’re going to take a whole heaping hell of a lot of bludgeoning damage(Meteor Swarm SRD recommends 20d6 fire along with 20d6 bludgeoning) and rather than simple fire, let’s make it psychic damage instead, as the sheer terror of this extra-dimensional hell rock infests the area around it. Now it is time to pull from the Black Tentacles spell, as the next turn a radius around the meteor lashes out snaring all who fail to dodge its mighty grasp. Finally, its time for a good old fashion explosion, take those poor souls who were snatched up and nuke the area around them, causing a solid fireball’s worth of damage. If that isn’t enough I recommend making the meteors eggs for aberrations such as Slaad(solid alien reference) or theming them to your respective dungeons.
As a final note, take the levels as a simple reference, with a little damage tuning and re-flavoring, any of these can fit into a fight regardless of character progression. The escalation of force should never be used too heavy-handed and try not to have the boss be using damage modifiers greater than something it could use on its own turn. These should be used in order to fill out a bit of action economy, adding an effective element to a threatening creature, even on its off turn.
Kobolds, D&D Beyond https://www.dndbeyond.com/monsters/kobold
Wight, D&D Beyond https://www.dndbeyond.com/monsters/wight
Lich, D&D Beyond https://www.dndbeyond.com/monsters/lich
Meteor Swarm, D&D Beyond https://www.dndbeyond.com/spells/meteor-swarm