When dealing with the many iconic monsters of Dungeons & Dragons, players often have to contend with their lairs; after all, dragons and their dungeons are in the name of the game. How these places work has changed from one edition to the next, and even within the fifth edition changes can be seen with each new release.
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Dungeons & Dragons: 2025 Monster Manual FAQ
Here’s everything you need to know about the 2025 Monster Manual, including what’s new, what’s changed, and what you’ll find inside.
The 2025 Monster Manual revamped many old and iconic monsters as well as redefined what we understand as a lair. In this guide, we will explore how lairs work in the fifth edition of Dungeons & Dragons, and how you can make the most out of them.
What Is A Lair?
In the narrative of a story, the lair of a villain or a monster is their base of operations, where they go back to rest and regroup, and the place they are most familiar with. Depending on the monster, it can be a red dragon’s fiery cave, a vampire’s gothic castle, or anywhere a beholder chooses to call home.
To represent the upper hand these creatures gain when fighting in their lairs, Dungeons & Dragons gives them mechanical advantages, such as additional actions or special traps surrounding their homes. This is why most adventurers, if possible, will choose to lure the creatures out of their lair so they can have an easier fight.
Not all monsters have lairs, even if they are legendary creatures.
Only legendary creatures can have lairs, known as such for their complex mechanics, their legendary resistance, and legendary actions. In the 2014 version of lairs, they are added special actions that happened on a different initiative count than the monster’s, but in 2025, lairs interact with legendary actions directly instead of adding new ones.
How Legendary Actions Work
A legendary action is a limited pool of actions a monster can do outside its turn, specifically at the end of someone else’s turn. Most legendary creatures can only do three legendary actions before their own turn starts, but the 2025 Monster Manual has introduced creatures capable of more.
Since these actions can be quite catastrophic, they need to be balanced in some way. The 2014 Monster Manual gives those actions a ‘cost’, so the creature acts less when using them, while the 2025 version clarifies that some actions can’t be used again during the same round.
How Legendary Resistance Works
When a creature has legendary resistance, it means that it can choose to succeed a saving throw that it fails a limited number of times per day. In 2014, all legendary creatures could do this only three times per day, but the 2025 Monster Manual has creatures that can do this more often.
2014 Rules For Lairs
Lairs that follow the 2014 version of the books (including most publications before the release of the 2024 ruleset) affect the monster in two ways: regional effects and lair actions. Regional effects change how the terrain is shaped by having a legendary creature living nearby, and lair actions are something the creature can do while on its lair, on an initiative count separate from its own.
Regional Effects
These effects are themed around the creature, happening between one and several miles around its lair. They can range from simple cosmetic changes to the terrain, to rule changes like ignoring resistances or constant disadvantage on certain checks.
These effects make facing the creature even near its lair a challenge, since most negative effects won’t be triggered by it. Once the creature is gone from the area, the effects often dissipate in 1D10 days, regardless of the kind of creature involved.
Lair Actions
Lair actions, as stated before, happen in their own turn, but they are still controlled by the creature that owns the lair. Most are traps or natural occurrences that happen to target the players, hence why they have their own initiative turn.
A creature can’t take the same lair action it took last round, preventing the Dungeon Master from spamming the same action over and over again. When a creature has lair actions, its challenge rating goes up by one, to signify the risen difficulty.
2025 Rules For Lairs
As per the 2025 Monster Manual, regional effects and lair actions are no longer a thing. Instead, regional effects are now known as lair effects, and the monster gains additional uses of its legendary resistance and actions rather than gaining any new moves.
Lair Effects
Similar to regional effects, these effects happen in the vicinity of the creature’s lair, but it is always around one mile from it. The effects can range from no benefit from resting to taking more damage of the creature’s type, and some creatures even add negative elements to rolling a one in a D20 test.
Should the lair’s owner die or move its lair elsewhere, the effects end immediately. To signal this, all lair effects are deeply magical in nature, altering the terrain as little as possible, so it is easy to roleplay the end to nature’s alteration.
Fighting A Monster In Its Lair
All monsters have been revamped in some way in the 2025 Monster Manual, with the designers wanting all relevant effects to be inside a creature’s stat block. This is why fighting a monster in its lair has been simplified, keeping the deadly factor while not necessarily adding any new complexity.
As such, when a monster from the 2025 Monster Manual fights adventurers in its lair, it gains one more use of legendary resistance and one more legendary action per round. On defeat, players earn more experience than if they fought the monster elsewhere, but the monster’s challenge rating doesn’t change.
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