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When dealing with the many iconic monsters ofDungeons & 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.
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 istheir base of operations, where theygo back to rest and regroup, and the place they aremost 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 representthe upper handthese creatures gain when fighting in their lairs, Dungeons & Dragons gives themmechanical advantages, such as additional actions or special traps surrounding their homes. This is why most adventurers, if possible, will choose tolure the creatures out of their lairso 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 areadded special actionsthat happened on a different initiative count than the monster’s, but in 2025, lairsinteract with legendary actions directlyinstead of adding new ones.
How Legendary Actions Work
A legendary action isa limited pool of actionsa monster can do outside its turn, specificallyat the end of someone else’s turn. Most legendary creatures can only dothree legendary actionsbefore their own turn starts,but the 2025 Monster Manual has introduced creatures capable of more.
Since these actions can bequite catastrophic, they need to be balanced in some way. The 2014 Monster Manualgives those actions a ‘cost’, so the creature acts less when using them, while the 2025 version clarifies thatsome actions can’t be used againduring the same round.
How Legendary Resistance Works
When a creature has legendary resistance, it means thatit can choose to succeed a saving throwthat it fails a limited number of times per day. In 2014, all legendary creatures could do thisonly 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 effectsandlair actions. Regional effects changehow the terrain is shapedby having a legendary creature living nearby, and lair actions are somethingthe 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 betweenone and several miles around its lair.They can range fromsimple cosmetic changesto the terrain, to rule changes likeignoring resistancesor constant disadvantage on certain checks.
These effects make facing the creature even near its lair a challenge, sincemost negative effects won’t be triggered by it. Once the creature is gone from the area, the effects oftendissipate 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 stillcontrolled by the creaturethat owns the lair. Most are traps or natural occurrences that happen to target the players, hence why they have their own initiative turn.
A creaturecan’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 aslair effects, and the monster gainsadditional uses of its legendary resistance and actionsrather than gaining any new moves.
Lair Effects
Similar to regional effects, these effectshappen in the vicinity of the creature’s lair, but it is always around one mile from it. The effects can range fromno benefit from restingtotaking 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 beenrevamped in some wayin the 2025 Monster Manual, with the designers wantingall 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 gainsone more use of legendary resistanceandone more legendary action per round. On defeat, playersearn more experiencethan if they fought the monster elsewhere, butthe monster’s challenge rating doesn’t change.
