Poison Lands (Underdark) (5e Environment)

From D&D Wiki

Jump to: navigation, search

The Poison Lands (Underdark)[edit]

My companions are dead or lost which amounts to same thing. I only live because of the magic of my cloak. How long have stumbled through this infernal fog? An hour perhaps? The cavern floor has climbed and fallen and the ceiling lowered so that at one point I had to walk bent double. But now the walls have widened and - is it my imagination? - the sickly ohcre mist is thinning...

Strange golden lights float in the air and I stare up at the toadstool which looms to twenty feet above me. Perhaps my cloak hasn’t fully protected me and I’m as addled as a halfling at a harvest festival. No. Not even the most fevered drunk could invent the hideous crawling bugs that scrape at the surface of the mushrooms or the things that fly in lazy beats through the gloom...

Creatures are following me now, they are fleeting shadows in the oppressive golden haze - how many of them is hard to be sure. My gut says too many to fight. I’ve got to escape this timeless hell. Then I see it - a square of clarity against the yellow. An exit surely! I lunge toward it, hearing howls in response from my pursuers. My elation turns to horror as the true nature of my objective is revealed, but it’s too late. My outstretched hand plunges through the clear wall and my arm is gripped and pulled onward. Only at the last moment had I seen that I was not reaching for an opening, but toward a … perfect … transparent … cube.

The deep Underdark has many dangers to test a brave adventurer, but only the foolish would pass into the yellow mists of the Poison Lands. Nothing can survive in the noxious miasma that steals the breath and veils the eyes - or can it!?!

Travelling the Poison Lands[edit]

Entering the Outer Veil[edit]

The Poison Lands extend for 120 miles square in a labyrinth of numerous levels, they connect to greater Underdark in numerous places. Any traveller with the misfortune to find a path to the Poison Lands will be confronted by an opaque wall of yellow gas, entering will cause breathing creatures to immediately take 2D6 poison damage and have their visibility reduced to 5’ (Includes Darkvision). Each subsequent minute exposed to the gas will cause a further 1d6 of poison damage. The gas is also flame suppressing - torches and natural fires will dim to embers and any fire-based attacks are at a disadvantage and cause half-damage (bonuses stack).

Most of the unfortunate souls that enter never get further than a few hundred yards before being overcome, but should you survive the first mile or two, the gas thins and a toxic wonderland awaits.

The Poison Meadows[edit]

Once beyond the Outer Veil the noxious gas is less dense and golden motes hang in the air shedding a dim light. Strange shadows loom in the fog hinting at treeless forests. Many-legged things crawl and fly.

Unprotected breathing causes just 1d6 poison damage per hour. Visibility is normal for 30’, Slightly obscured to 60’, and heavily obscured beyond. The flame suppressing effects are reduced and have no effect on fire damage, though natural fires are less vigourous.

The Deep Stink[edit]

Delving into the deeper levels of the Poison Lands brings you to caverns that have fewer living things. The gas is denser here again and fumaroles pump out noxious smokes.



The Poison Meadows have no normal plants but it is home to numerous giant fungi and tree-like rock formations that have feathery fronds at the top that wave back and forth. These rock formations are very similar to corals and come in a great many forms and colours.


The Poison Meadows are full of life but much of it poses no danger beyond unsettling the novice traveller. There are things that skitter and crawl, armoured bugs with too many legs, centipedes with six wings that fly in lazy loops, and strange fleas that have the annoying habit of getting caught in your hair or beard.


Monster Distribution
Myriapoda* Swarm Common
Giant Myriapoda* Common
Oozes, jellies, puddings and slimes Common
Giant Antlion Uncommon
Giant Antlion lacewing Uncommon
Rustmonster Rare
Umberhulk Rare
Salamander Very Rare
Green Dragon (underdark variant) Very Rare
Beholder Very Rare

(*Centipedes or re-skinned giant insects)



Myconids are commonly found in small 'gardens' throughout the Poison Meadows.

Halflings (Half-Green-Dragon variant)[edit]

Several small communities of halflings eke out a simple existence farming the giant fungi and 'corals'. Due to their heritage they are immune to the poisonous atmosphere and have discovered that the 'coral' is especially effective against the troublesome oozes. All halflings carry ooze repellent powders and use 'coral' weapons and armour.

Kobolds (Poison immune variant)[edit]

Kobolds live in constant conflict with their halfling neighbours, but occasionally they also send raiding parties out into the greater Underdark.

Firenewts (Poison immune variant)[edit]

The Deep Stink is home to wandering bands of Firenewts that sometimes venture to the upper levels.

Adventure Hooks[edit]

"They’d be crazy to follow us"[edit]

Your party is pursued by vastly superior enemies, caught between a rock and a hard place, your only option is to plunge into the yellow fog.

Tip-toe through the toxins[edit]

Time is short! The fastest route is straight through the Poison Lands.

"It’s spreading!"[edit]

The noxious gas is expanding by the day and threatening the lands beyond. You must find a way to stop it.

"It’s shrinking!"[edit]

The Poison Lands have been your home for generations protecting you from the horrors beyond its veil. Now your community is under threat and you must journey to the secret depths to save your homelands.

"They went in there!?!"[edit]

You’re pursuing someone or seeking something, the trail leads to the Poison Lands.

(0 votes)

Back to Main Page5e HomebrewEnvironments

Home of user-generated,
homebrew pages!