Lair Actions 5e

What Are Lair Actions?

Lair Actions occur in combat when creatures of significant power, like dragons, sphinxes, or liches, fight within their domain.

Unlike Legendary Actions, Lair Actions occur on Initiative count 20 (losing Initiative ties) and offer thematic abilities that reinforce the creature’s effects on its surroundings. Whether it’s an Adult Black Dragon summoning a cloud of foul insects or an Aboleth summoning illusions to mess with invaders’ minds, these effects are powerful and can swing the tide in the lair owner’s favor.

When used, effects caused by Lair Actions typically last until the creature uses that Lair Action again, the end of its next turn, or until the creature dies.

Lair Actions in the new Core Rulebooks

Lair Actions have been removed from the new Core Rulebooks in favor of providing legendary creatures with additional Legendary Actions and Legendary Resistances while in their lairs.

This has been accompanied by a shift in Legendary Actions to make them less generic and more dynamic, allowing legendary creatures to use more special abilities through a round of combat.

While that may be the case, we love Lair Actions here at Arcane Eye, so let’s dive into this beloved system!

How Lair Actions Impact Combat

The main function of lair actions is to improve the legendary creature’s action economy, ensuring that a boss monster doesn’t get overwhelmed—especially when they are the single combatant against a full party of adventurers.

These effects essentially give the legendary creature another action, allowing them to impose debuffs, control the battlefield to their enemies’ disadvantage, or dish out more damage, depending on the type of creature.

For example, an Adult or Ancient Red Dragon could use the following Lair Actions while in their lair:

• Magma erupts from a point on the ground the dragon can see within 120 feet of it, creating a 20-foot-high, 5-foot-radius geyser. Each creature in the geyser’s area must make a DC 15 Dexterity saving throw, taking 21 (6d6) fire damage on a failed save, or half as much damage on a successful one.
• A tremor shakes the lair in a 60-foot radius around the dragon. Each creature other than the dragon on the ground in that area must succeed on a DC 15 Dexterity saving throw or be knocked prone.
• Volcanic gases form a cloud in a 20-foot-radius sphere centered on a point the dragon can see within 120 feet of it. The sphere spreads around corners, and its area is lightly obscured. It lasts until initiative count 20 on the next round. Each creature that starts its turn in the cloud must succeed on a DC 13 Constitution saving throw or be poisoned until the end of its turn. While poisoned in this way, a creature is incapacitated.

Ancient Red Dragon – 2014 Basic Rules

In the 2014 Monster Manual, a creature’s CR wouldn’t increase if it was encountered in its lair, nor would it provide additional XP, which is an oversight that was fixed in the 2025 Monster Manual. For example, now, when you fight an Arch-hag in her lair, the party is rewarded 41,000 XP as opposed to 33,000 XP if she was encountered outside of her lair.

This helps you balance encounters using the new XP Budget per Character system in the 2024 DMG rather than relying on the (inherently flawed) CR system.

Group by Theme: Lair Action Options

In the 2014 Monster Manual, not all legendary creatures with lairs got Lair Actions. For example, Vampires have Legendary Actions and Legendary Resistance, but their lairs only came with a couple of regional effects and some information about minions. For creatures that received Lair Actions, different creatures had different options based on their unique nature and the typical terrain of their lair. Here’s a breakdown based on theme:

Dragon’s Lairs

The treasure-filled dragon’s lair has been a top-tier fantasy destination since The Hobbit (and probably much before that). However, it’s worth noting that only adult and ancient dragons can access Lair Actions to protect their hoards. While a dragon of any age might be able to blast their foes with a breath weapon, only elder dragons can summon the following effects in their lairs:

• Red Dragons cause magma to erupt, shake the ground with tremors, and release volcanic gases that can poison creatures.
• Black Dragons pull creatures into the water sources in their lair, summon swarms of insects, and spread magical darkness.
• Gold Dragons can see into the future to gain an advantage in combat and banish creatures to a dream plane.
• White Dragons summon ice walls, create a freezing fog, and cause jagged ice shards to fall on its prey.

Undead and Necrotic Entities

• Liches regain spell slots, blast enemies with necrotic damage, and summon tortured spirits.
• Mummy Lords can find living creatures, gain Advantage against Turn Undead effects, and hamper spellcasters.

Mystical and Otherworldly Lairs

• Sphinxes use their ambient magic to alter the flow of time to reroll Initiative, make creatures older, and reverse their positions.
• Beholders cover the surfaces in slime, grasping appendages, and eyeballs.
• Unicorns extinguish flames, help native creatures hide, and suppress curses.

Legendary Actions vs. Lair Actions

Legendary Actions allow monsters to act directly after another creature’s turn, whereas Lair Actions always happen at Initiative count 20. Also, creatures get a certain amount of Legendary Actions per round whereas there is only ever one Lair Action per round.

In the 2014 Monster Manual, Legendary Actions were more used to increase the frequency of a creature’s basic attack rolls, like the dragon’s claw or tail attack, while Lair Actions provided thematic, battlefield-wide effects.

Adding Lair Actions to Creatures

If you want to spice up a fight and give Lair Actions to a creature who normally doesn’t have them, you’ll have to consider its challenge rating and expected damage per round. If you’re using the 2014 rule set, you can use the Monster Statistics by Challenge Rating table as a guideline to ensure the total damage—across attacks, Legendary Actions, and lair effects—aligns with its intended difficulty.

To get an accurate calculation of Damage/Round for Lair Actions, you might have to calculate its damage output each round for the first three rounds of combat and take the average.

Designing Lair Actions

Lair actions should reflect the creature’s nature and environment. A kraken might generate crushing whirlpools or electrify the water. When balancing damage, factor in the frequency of lair actions (usually once per round on Initiative count 20) and whether they affect multiple targets. Environmental hazards, forced movement, or battlefield control effects can be just as impactful as direct damage, though it’s harder to factor these into the monster’s CR.

Lairs are Layers of Fun

Lair Actions are great ways to create a dynamic battlefield for your combat encounter, which helps introduce more strategy to combat that’s supposed to be legendary. Whether it’s a dragon’s volcanic cavern erupting with bursts of lava or a lich’s chamber pulsing with necrotic energy, these actions ensure that legendary foes feel as powerful as their reputations suggest. So don’t just make your villains strong—make their home turf a challenge worthy of the fight!