Making a Lich Lair

[yonah]

I'm trying to make a lich lair but I've never dmed something this high level before. My players are level 20 (it's a two-shot). Does anyone have advice for traps or dungeon layout or literally anything? I have a lich sheet and that's about it.

[J-H]

I'm assuming you want it to be fairly lethal and dangerous.

1) Use Guards and Wards extensively. It covers a lot of territory. The hallway fog may impede their sight, but the Lich's allies (like the skeleton with the Wand of Lightning Bolt) aren't hindered by it.
2) Use Symbol extensively to wear them down. Note you can pair multiple Symbols in an area (like: Compulsion, go down the side hallway. Side Hallway has Symbols in it). You can have Symbols on walls covered by Tapestries. Mage Hand/Bonus Action Mage Hand to yank a tapestry down and expose a Symbol.
3) Summons: There should be some summons or bound creatures. For a 20th level party, you probably want to introduce 1-2 lesser foes per round to split their attention. Maybe the lich has a lesser portal somewhere, or a Dire Hellwasp Swarm spawner, or a back area (that the party hasn't seen) with golems that straggle onto the battlefield according to their move speed. If it has access to True Polymorph, then it can have a bunch of CR 9 creatures just sitting around from casting it 1/day. Heck, maybe it has Flesh to Stone'd a bunch of Mind Flayers or Devils as declorations, and opens the battle by going "I Wish they were all affected by Stone to Flesh."
4) Revamp the Lich. More HP. Better spell list. INT to damage. Add a Legendary Action (costs 2 actions) to cast a leveled spell in his off-turn, then give it 4 legendary actions per round instead of 3. Make sure the lich wears all the relevant magical items from its hoard. Give it 3 9th level spells slots, 4 8th level, 5 7th level, etc. If it casts Magic Missile, it should be upcasting to like 6th level for 8d4+8+6 damage, not just 3d4+3.
5) Buffs: It knows the party is coming. Death Ward, Freedom of Movement, Mirror Image. Consider letting it concentrate on two spells at a time, like Invulnerability and, I don't know, Dominate Monster. Start the battle with Greater Invisibility up.
6) Assume it knows the party coming and has scried on them. Optimize tactics and saving throw targeting.

It's a high-INT caster with decades to prepare. If you can think of it, the Lich has done it five times. Go ham.

[Zhorn]

Layout should be something that is either practical for the lich's needs, or is not of such a design that would inconvenience them.
Don't go for long errant corridors unless it is something the lich wouldn't care about or they wouldn't have to deal with, such as if they planeshift or teleport in and out a lot.

Traps should be trivial for the lich to bypass, or not be of any risk to the lich at all.
Like how weight based traps are good for kobolds as their are too light to trigger them themselves, the lich's lair would be trapped in a way they can either ignore the traps, or not be concerned if they were to trip them anyway. Poison gas traps are a big one, magical charms and paralysis, exhaustion inducing effects, as the lich's immunities will mean these will all fail to cause even the slightest issue to them.

Undead minions galore. They don't need to be a constant active thing, but with the lich's inclination to devour souls to sustain themselves, a base collection of bodies around their lair should be reasonable to expect. Why waste the materials? Should the lich be aware of impending intruders, they could spend some time raising a security force to soften foes up or capture/restrain/eliminate lesser opponents before the lich even needs to pay them serious attention.

Guards and Wards, along with Private Sanctums. A lich is fundamentally a wizard, and so would use the same magical protections a wizard would use on their own private base. They've had plenty of time to build up their fortifications, so lots of those permanent spell effects would have been achieved. Some areas should still be viable locations for scrying and or teleporting/planeshifting, but the needed always overlap. Maybe the scrying location is warded from teleporting, but the teleport location is shielded from scrying, etc.

Darkness, both magical and ordinary. Truesight means the lich doesn't care about light most of the time, so why make it easier for would be adventurers.

If there are any mechanical traps, you want a way to explain how often they are checks/reset. Not mandatory, but depending on how high profile your lich is, this might get questioned. Grunt work for either undead minions or lesser slave races the lich has under their control.

[Unoriginal]

I'm trying to make a lich lair but I've never dmed something this high level before. My players are level 20 (it's a two-shot). Does anyone have advice for traps or dungeon layout or literally anything? I have a lich sheet and that's about it.

You could make the lair an extraplanar one. Do you find one of the planes fun?

[JellyPooga]

Layout should be something that is either practical for the lich's needs, or is not of such a design that would inconvenience them.

This. So much this.

If I were going to spend an eternity somewhere, I'd want it to be at the very least comfortable. Preferably palatial. With a view.

So ditch any ideas of dank crypts and dark, musty dungeons; that sort of stuff is for chump necromancers and petty hedge-mages fighting over scraps. This is a powerful ever-living Lich we're talking about. Give him a Sky Palace at the top of the highest mountain in the Plane, where if the cold don't kill you, the lack of air from high altitude will. Have it be sumptuously furnished with all the luxury that money, power and magic can buy. Display fashions and tastes from across multiple centuries of existence. Give him a home.

If the "heroes" aren't gasping for air or freezing to death when they knock on the front door, invite them in. No trapped corridors. No inconvenient, aggressive and smelly undead minions junking up the place (have summoned creatures/forces or Constructs if you need servants). No "monsters". Offer them tea and a warm robe. Show them to the massage parlour and hot spring. Serve dinner and offer constructive and engaging conversation. Be polite. Let them stay a while in the lap of your luxury.

Get on with your day when they drop dead from whatever devious machinations you have prepared for their demise. Poison the tea. Trap the luxuries you aren't going to use (e.g. install a "flush" on one of the hot-tubs that empties over a 1000ft drop, or leave cursed books lying around with tempting titles like "How to defeat a Lich"). Summon masseurs with a vice-like grip. Be inventive. But be nice.

[Incorrect]

If the "heroes" aren't gasping for air or freezing to death when they knock on the front door, invite them in.

You could invite them in, show them around and be a gracious host. Until they arrive at the throne room.
At that point the lich teleports out; sounds the alarm, activates the traps, and releases the hounds. Now the dungeon crawl is a battle to escape, and the final boss fight is in the lobby.

[Unoriginal]

Also, a Lich's Lair is a display of their personslity. Literally so, of they have Regional Effects.

You could have a Bladesinger Lich whose Lair is a colosseum in Acheron, where extraplanar gladiators and pugilists gather to train and fight.

You could have a Diviner or Illusionist Lich whose Lair is half-house of mirrors, half-panoptikon, which alters the ranges and AoEs.

You could have a Lich who spent the last millenium studying force effects, resulting in their Lair to have more and more of its features, furnitures, items, even servitors replaced by copies made of force.

You could have a Lich whose Lair is in the body of a truly enormous bird.

You could have a Lich studying magic that let's you change shape and size, leading to rooms and corridors that can only be traveled through by someone of the right build.

You could have a Lich who tried to best a being of great power and lost, resulting in the spellcaster being imprisoned in their own Lair.

You could have a Lich who's obsessed with eyes, and who has been trying to turn the Eye of Vecna into their new philactery.

Fun fact: a Lich's Lair is called a Doom. A specific Doomis often called [name of the Lich]doom, in one word.

[Biffoniacus_Furiou]

Its lair should have environments that are outright hostile to any intruders.

An underground lair with no ventilation wouldn't have breathable air, living creatures that enter would need a necklace of adaptation or similar or risk suffocating.

Plants that produce poisonous gasses would be welcomed, even cultivated, in its lair, considering it's immune to poison damage and the poisoned condition.

Extreme cold/heat wouldn't bother it at all because it's immune to exhaustion.


They shouldn't be at 100% daily resources when they fight it, they'll need to fight through its minions and expend resources first.


Make its lair include multiple biomes. Maybe they'll enter through a glacier (extreme cold), which should be a maze filled with cold-themed minions. After that they'll find a hotspring under the glacier, a garden that fills the air in the chamber with poisonous spores. That can have encounters with more minions who are immune to poison, maybe undead gardeners and hostile plants and plenty of gas spores. Maybe also some kind of ceiling-clingers that drop down onto the characters who like to avoid melee. Don't be afraid to throw a dozen or more low to moderate CR monsters at them at once, add reinforcements (sneaky reinforcements are best) after a few rounds depending on how easily they're eliminating opponents, then a final wave of reinforcements with a big bruiser type (golem?) as a miniboss. Then they'll go back into glacial chambers to find the lich's private rooms.

His section is sealed off from the rest of the complex by a wall of ice, completely air-tight for centuries. Burning candles alone is sufficient to use up all the oxygen, making it inhospitable for creatures that breathe. Swap out one of its spells for Project Image, which it can use to observe and issue commands anywhere within the spell's range. Also say he can perform his third lair action from the image, in order to harry intruders and prevent them from resting. The project image can go through walls, and ice is transparent enough on the surface that it can see them without being exposed to attacks that would cause the spell to end. The tunnels that lead to it would have more enemies and even better traps. Maybe the glacier has a cylinder cut out but held in place, when they go through the tunnel that's in that section the cylinder drops a distance. It falls out the bottom of the glacier and plunges into the ocean, instantly flooding the tunnel with frigid water and leaving them with nowhere to take a breath unless they swim out from under the glacier. (The glacier is partially over land, partially over water.)

Its private rooms should also have minions, likely undead and/or constructs who can clean and assist it with tasks. The whole area should be lavishly furnished with rugs and tapestries and chandeliers, but still all incredibly cold. The room the lich chooses to fight them in should have a glass sphere at the center, at the start of the fight the lich casts an 8th level lightning bolt into it to charge it up. The lightning bounces around inside of it and then the sphere fills the room with a 20-ft. radius of arcing electricity and smoke. Treat it as an incendiary cloud spell that doesn't require concentration and deals lightning damage instead of fire damage. Instead of a wind dispersing it they would need to dispel or destroy the sphere (fairly high AC due to being difficult to damage, it's heavily obscured, immunity to all but bludgeoning, piercing, and slashing damage, enough hp that it takes 3-4 hits to break it). The lich of course would end every turn within the heavily obscured area since it's immune to lightning damage, only stepping out to cast a spell if necessary and then moving back in. While obscured it would use its disrupt life legendary action every turn and likely its lair action that regains spells.

[The_Jette]

Something that I'll be trying in an upcoming game that I'm running is to have a lich that is living on a "Ghost ship." It'll be a large ship with a permanent "Unhallow" effect that has the added bonus of turning any creature to die on it into a skeleton under the control of the Lich. So, it's a mobile base that is manned by an undead crew, so the lich can spend most of its time studying and pouring over tomes in the bowels of the ship. And, should some particularly powerful group destroy most of his crew, he can just reanimate them once he's destroyed the adventurers. Then, it's back to studying. Of course, he'll occasionally stop in at some port town and bring on a bunch of people to kill so that he can build up a bigger crew. But, if he didn't, how would the adventurers have ever heard of him?

[KorvinStarmast]

You could invite them in, show them around and be a gracious host. Until they arrive at the throne room.
At that point the lich teleports out; sounds the alarm, activates the traps, and releases the hounds. Now the dungeon crawl is a battle to escape, and the final boss fight is in the lobby. I like the way you think. In the background, have Eric Burdon/The Animals playing We Gotta Get Out of This Place

Also, a Lich's Lair is a display of their personslity. Literally so, of they have Regional Effects.{snip}
I am stealing most of that.

Fun fact: a Lich's Lair is called a Doom. A specific Doomis often called [name of the Lich]doom, in one word. For slightly better wordplay, I'd refer to "a specific Doomesne" as the lair of a specific Lich.

Acererakdoom; hmm, it ain't San Simeon, nor Xanadu, but it does have a certain ring to it.

[yonah]

Ahh these are all such good ideas! Thank you, everyone! I definitely buffed my lich and I've got a bunch of lore for her so I'm onto figuring out minions now.