The Demi-Plane of Nightmares for 5th Edition (Basic Version)

This setting is free for you to use in your Fifth Edition Dungeons and Dragons campaigns. The map is free for personal and commercial use from Dyson Logos. Notes are free for you to use, but not commercially. And the art is borrowed from Jota Cravo.

It’s finally happened. My players have emerged from the Dyson Mega-Delve’s Mushroom Cavern and reached the Demi-Plane of Nightmares. It is here that they will face the exiled devil, the Duke of Nightmares, in order to reclaim the Arm of Leufresia so they can save their friend, Betha.

What follows are my notes for the Demi-Plane of Nightmares. I’m using one of Dyson Logos’ maps (of course) for the Demi-Plane of Nightmares. Unlike most of Dyson’s maps where I go with his description and build it out, I’m using my own story bits to populate it.

Here’s the map with labels I added:


General Features

Unless otherwise noted, these are the general features for this map.

Distance. Each hex represents 3 miles.

Terrain. Most of the terrain is swampy and considered difficult terrain with the exception of the Blasted Crags, the environment surrounding the Duke’s Tower and the Hopeless March. Travel times are cut in half.

Fog. All forested areas have a patchy blanket of fog covering them. All creatures have disadvantage on Wisdom (Perception) checks that rely on sight in these areas.

Weather. It is almost always overcast on the Demi-Plane of Nightmares. There is a 35% chance every 6 hours that it starts raining and a 50% chance that the rain is heavy precipitation (see page 110 in the Dungeon Master’s Guide).

Time. Time moves oddly in the Demi-Plane of Nightmares. At the start of each “day”, roll a 2d4. That is the number of hours it is light out (there is no sun here). Once it becomes “night”, roll 3d6. That is the number of hours of darkness. In addition, time in the Demi-Plane of Nightmares is fast in relation to the Prime Material. For each hour spent in the Demi-Plane, only one minute passes in the Prime Material.

The Duke’s Influence. The Duke has full control over the Demi-Plane of Nightmares and knows the exact location of every creature and object there. In addition, the entire demi-plane counts as desecrated ground giving undead advantage on saving throws. It is immune to the effects of holy water.

Random Encounters. The Demi-Plane of Nightmares is host to all sorts of horrors. Once every hour, roll a d20. In the daytime, if the result is an 18 or higher, a random encounter occurs. The chance increases to 17 to 20 at night. The nature of the encounter is determined by where the characters are when it happens.


Areas and Points of Interest

1 – The Mushroom Cavern

The dimensional portal that brings the characters back to the Prime Material is found at the mouth of the cave leading to the Mushroom Cavern. Outside of powerful magic, it is the only way to return to the Prime Material from the Demi-Plane of Nightmares.

Outside of the mushroom cave are moors.

2 – The Nightmare Grove

The nightmare grove is a forest full of strange trees known as Dreamer Willows. A Dreamer Willow’s base looks like the top of a huge, partially-submerged giant’s head from which a tall, sagging tree grows. These aren’t giants, though. They’re actually the manifestations of dreaming humanoids on the Prime Material.

At the tip of each of the tree’s branches are dream fruit. There are two varieties of dream fruit: good dream which fruit glows brightly and bad dream fruit which looks dark and rotten.

Biting into a good dream fruit gives a creature access to the dreams and hopes of the creature to the Dreamer Willow is connected. In addition, the fruit heals 1d4 + 1 hit points when eaten.

On the other hand, biting into a bad dream fruit gives a creature a look into the nightmares and fears of the creature that the Dreamer Willow is connected to. Eating this fruit deals 1d4 + 1 psychic damage.

Anyone that bites into the dream fruit of a creature that they already know, regardless of the type, has advantage on Wisdom (Insight) checks involving that creature for the next 30 days.

Random Encounters in the Nightmare Grove

Use the random encounters table for Swamp Encounters (Levels 5-10) on page 106 of Xanathar’s Guide to Everything, except with the following changes:

06 – 07: 1 spectator

08 – 09: 1 diabolus

14 – 16: 1d3 diaboli

17 – 19: 1 Kirby

31 – 33: 1 ocularon with 1d4 animated eyeballs

85 – 86: 1 beholder

89 – 90: 1d6 + 1 diaboli lead by a diabolus bellator

3 – The Blasted Crags

Beyond the Nightmare Grove is a series of dangerous peaks and canyons known as the Blasted Crags. At the center of this nightmare terrain is where the Duke’s Iron Tower stands.

Unlike the groves and most areas on the Demi-Plane, this area is not submerged by swamp waters or blanketed in patchy fog. Instead, the crags are subject to strong winds, extreme heat during the day, and extreme cold during the night (all detailed in the DMG p110). The entire region is very difficult to pass, cutting travel times down to 1/4th.

Random Encounters in the Blasted Crags

Checks for encounters in the Blasted Crags happen once every hour and occur on a roll of 17-20. Use the random encounters table for Mountain Encounters (Levels 5-10) on page 104 of Xanathar’s Guide to Everything, except with the following changes:

01 – 02: 2d4 + 1 diaboli

07 – 08: 1 kampian

16 – 20: 1d8 + 1 winged ankhegs

51 – 52: 1 onlooker

55 – 56: 1d3 + 1 diabolus bellators

84 – 85: 1d10 + 1 starspawn grue plus 1 star spawn mangler

95 – 96: 1 dreemeen

4 – The Duke’s Iron Tower

See the Duke’s Iron Tower map for more details.

5 – Nezznar’s Dreamer Willow

This opening in the middle of the Nightmare Grove hosts a thick tangle of Dreamer Willows roughly 1 mile in diameter. At the base of each of the willows is a giant doppelganger’s cranium. This is where all of Nezznar’s disciples dream as one, creating the same dark dreams. All but one of the dream fruits are built on the nightmares of the doppelganger’s former lives. The single fruit that grows brightly is the dream of all of the Planes being shut off from the Prime Material and magic dying.

Nezznar’s tree is protected by six diaboli, two diaboli bellators, and three spectators. They’ve been commanded by the Duke to protect the tree at all costs.

6 – Lake Ulk’chaa

The Duke isn’t the only being of great power on the Demi-Plane of Nightmares. At the center of black lake sleeps Ulk’chaa, an elder aboleth. Ulk’chaa sends its slimy henchmen out into the groves north of his lake

Note: it’s doubtful that my players will go here or sections 7 and 8, but I might flesh this out as a side quest later on.

7 – The Dead Groves

Ulk’chaa’s influence has tainted the Dreamer Willows on this part of the Demi-Plane. While most of this grove is similar to area 2, many of the trees to the south sprout up all sorts of monstrosities including bizarre beholder variants.

8 – The Hopeless March

Like the blasted crags, this barren, gray desert is not submerged by swamp waters or blanketed in patchy fog. Instead, the march are subject to strong winds, extreme heat during the day, and extreme cold during the night (all detailed in the DMG p110).

Random Encounters in the Hopeless March

Use the random encounters table for Desert Encounters (Levels 5-10) on page 96 of Xanathar’s Guide to Everything, except with the following changes:

01: 1d6 azers

36 – 40: A humanoid boneyard.

67 – 68: 1d4 + 1 diaboli

69 – 70: 1d3 ghosts

73: A dead deva.

74 – 75: 1 diaboli bellator

93: 1 stonejaw ankheg

96: 1d3 young blue dragons

00: adult blue dragon


Thanks for reading!

This was a quick and dirty addition to my D&D notes, but unfortunately, I’ve been feeling a little lousy lately. I’ll probably flesh it out a bit more as I go.

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See you next time!

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