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Through the Shadowdeep, from Karameikos to the Hollow World

by Francesco Defferrari from Threshold Magazine issue 14

Through the Shadowdeep

From Karameikos to the Hollow World

by Francesco Defferrari

The ancient inhabitants of the depths

The land that is now Karameikos has existed for billions of years, long before the Traldars, long before Taymora. It has been higher, lower, under the sea, desert or wooded, inhabited by elementals, worms, oozes, insects, araneas, dinosaurs, fairies and giants for ages before men, and by other men before the ones that inhabit it now. Most of the ancient races have disappeared into history and not much is left of them, yet each race that inhabited this land has left at least some trace of itself behind, to be discovered in the present.
Sometimes they have left traces in ancient ruins below ground, sometimes they have left forgotten tombs just below the surface, and sometimes they have left secrets deep under the earth, down into the Shadowdeep1.

This article is an expansion of what was already written by me and published on the Vaults here: and inspired my many other contributions:
See also the category Shadowdeep2 in the Vaults:
And also several threads on The Piazza:
Mystara’s Underdark
Almanac of the Subterranean Known World?
Collaboration Proposal: Expanding the Shadowlands
Bree-YAAAARk! Piracy in the Depths of the Earth
Descent into the Depths of Mystara (thought exercise)
Outer World: Beneath the Atlan Tepe Mountains, 8 mi per hex
Outer World: Beneath the Adakkian Mounts, 8 miles per hex
Where more and alternative theories and idea can be found about Mystara’s Shadowdeep.

An incredible voyage

Imagine travelling from the Outer to the Hollow World the hard way. On foot, walking through mazes of pitch black tunnels and caves. But the greatest dangers of this travel will obviously be the inhabitants of these lands far from the sun. In canon Mystara some people now in the Hollow World had to face this incredible trip, for example the Shattenalfen and the Icevale elves. The distance from the Outer to the Hollow World is about 1,600 miles3 in a straight line. As there is nothing like a straight line, a trip should take into account at least 3600 miles of actual distance in irregular terrain and in the utter dark, and with many dead ends. Probably such a voyage should take 6 months minimum in an exceedingly optimistic prevision, but one year or two is much more realistic. Do you dare to descend into the Shadowdeep?
In canon Mystaran products, there are several mentions of routes connecting the Outer and the Hollow World:
- There is the Coliseum in Thyatis city, which sits atop a deep cavern entrance that reportedly leads all the way to the Hollow World. The Gladiators (at least one order of them) have long considered themselves protectors of the city from the Things That Lay Beneath4.
- In Gazetteer 13 The Shadow Elves there are mentions of Shattenalfens and Azcans from the Hollow World having reached the Shadowlands.
- There is the path which links Atruaghin's Palace in the Outer World to the ruins of Quahnahuac in northwestern Azca in the Hollow World.
- A lengthy tunnel system beneath the Barleycorn Monastery in the Broken Lands of the Outer World leads to the ruins of Atacalpa in the western mountains of Azca (near Colima), featured in the module HWA1 Nightwail.
- A man and magically made tunnel links the Outer World village of Pittston on the island of Aegos to the town of Haldemar in Alphatian Neatharum in the Neathar lands, see Wrath of the Immortals boxed set and Poor Wizard’s Almanac.
- More possible connections could also be found in Threshold issue #9:, which theme was the Hollow World.

This article imagines a similar route from Karameikos to the Hollow World, with all the possible levels along the way and the many different creatures and cultures which could inhabit them. Some example maps are included, showing the area under Karameikos at different depths.

Notes on borders and neighbours

What's interesting to note here is the main directions are not 4 (NWES) but 6 (above and below) so any underdeep culture could have at least six main neighbour nations around. Yet in the underdeep travel is not easy and therefore, differently from the outside world, it could be very difficult to know of other cultures beyond those in the immediate vicinity, unless there is an easy connection or the culture has a penchant for explorations...

As there isn't much in canon about Karameikos underdeep, I would leave many underground cultures quite separate from each other, unless PCs change that.

The Shadowdeep

The Upperdeep

This region of the Shadowdeep is the one nearest to the surface and can be reached relatively easily from it, going down to a maximum depth of about 1 mile. Its inhabitants normally know of the existence of the surface and may be interested in exploring or even conquering it. This region was also described in details for all the Known World in my other article in this same issue, The Unknown World Trail Map part II.

1st layer, Dungeons, tomb and mines.

Approx. less than 100 feet deep from ground level5, down to 30 meters.
Normally less than 30 minute walk to reach the surface (without obstacles).

Tomb and mines in general are not very deep and not very extensive, as they are normally dug for a specific and limited purpose. A map of the many tombs and mines in Karameikos is not included here because even the bigger ones would appear too small in a country map. Subterranean locations are Included in several canon sources, such as the B series of modules, some Dungeon adventures and later products, see also here in the Vaults the index of Mystara products by David Keyser which includes suggested locations. A classic dungeon three levels deep will be generally no more than 50 feet below ground in its lowest point and even a megadungeon like Koskatep (see article in this and previous issues) is mostly over sea level as it is built inside a hill. Deeper dungeons could be lower, but rarely more than 50 meters down (165 feet) from ground level.
The common underground creatures of the basic modules should be quite common at this level, such as bats, black puddings, blast spores, carrion crawlers, cave toads, centipedes, chokers, feywings, fungoids, gelatinous cubes, hypnosnakes, giant beetles and other insects, giant leeches, giant lizards, giant slugs, ochre jellies and other oozes, rats, rhagodessas, ropers, rust monsters, scorpions, spiders, sporacles, stirges, white apes, worms, yellow mould. Some intelligent creatures should be quite common in the underground areas of Karameikos, as they appear in the B modules, in particular brutemen, humanoids, lizardmen, troglodytes and maybe also minotaurs and gargoyles. Under the main cities, Specularum in particular, wererats, hivebroods and undead are all appropriate and obviously human criminals and cultists of dark gods too.

2nd level, Dwarves and gnomes.

Approx. less than 800 feet deep from ground level, down to 243 meters.
Normally less than an hour walk to reach the surface.

The people inhabiting this level, the most famous being dwarves, gnomes and humanoids, typically maintain a tight relationship with the surface. Their communities under the earth and those over it are in constant trade and communication. Their caves are often inhabited by more or less the same creatures listed above that could be encountered in shallow caves near the surface. Other intelligent creatures who often inhabit this level of the Shadowdeep are lizardmen, troglodytes, brutemen, minotaurs, werecreatures and undead.

Karameikos second layer

In this layer, the central area of Karameikos is dominated by the gnomes and dwarves of Highforge, Eveskyr in their language. They have also several mines under many of the mountains of the north, but most of them are included in the first layer rather than here in the second one. Other intelligent races, however, border the gnomish and dwarvish subterranean lands. Toward Thyatis, there are the Halls of the Giants, the great underground cave dominated by the giants of Altenia. Minotaurs are common in the east of Karameikos, according to the gnomes dominated by the powerful dragon Argos, who is also the master of the subterranean regions of the Dymrak woods, inhabited by lizardmen and humanoids. Many brutemen, the Ancient Ones as the gnomes call them, live under the area of the Moor in central Karameikos, and some also north of the gnomish lands. Brutemen, however, are particularly numerous in the west, where they serve the powerful gold dragon Azem. The same is rumoured to be true for the lizardmen which live numerous under the Blight Swamp. Some underground lairs of the ogres and orcs of the west also reach as deep as this layer.
Under Mount Pavel, near the gnomish land, there is also the land of the “Stone People”, how the gnomes call geonids, rockmen and stone giants.
Lastly in the south, just east of Specularum, there is the Dark Domain, an underground territory dominated by the Church of Nyx, with numerous Uncorporeal and Undecayed6.
In some minor caverns from Specularum to Thyatis werebats and wererats are also present in this layer. To the north the gnomish lands have a direct connection to Rockhome, sometimes menaced by goblins who live underground in the eastern Orclands.
The gnomish territories in this layer are also often menaced by humanoids incursions coming both from above and from the layer below.

3rd level, Humanoids

Between about 800 and 2,000 feet beneath ground level, down to 610 meters.
Normally about two hours walk to reach the surface.

The people inhabiting this third layer of the Shadowdeep under Karameikos are mostly humanoids, with some minotaurs in the west. Normally these are the same clans which inhabit the surface of the nation7, but some unique clans exist which live almost exclusively underground, forced to leave in the darkness by defeats in war or excessive competition.
To the north there is the region of Deep Hollow, described by Giampaolo Agosta in his article of this same issue. To the south there is the Shadowdeep which lies under Ierendi and Minrothad, a region feared by the humanoids because reputed the domain of undeads8.
The west is mostly inhabited by troglodytes and manscorpions, with some pockets of humanoid territories. The east, toward and under Thyatis, is inhabited mostly by minotaurs, humanoids and wererats. Dwarves and gnomes sometimes dwell in this layer, if willing to face the risk of some humanoid encounters to search for particularly promising veins of metal of deposits of gems.

4th level, Shadowelves and earth creatures

Approx from 2,000 to 5,000 feet deep from ground level, up to 1,500 meters or 1 mile.
Normally about 1 day walk to reach the surface.

The people inhabiting this fourth layer of the Shadowdeep, last of the Underdeep, under Karameikos are mostly geonids and rockmen, and other creatures with a deep relation with earth, including some earth elementals. Beholders and medusas are also relatively common on this layer. From under Specularum and toward Thyatis there are also several hivebrood nests9. Deep glaurants sometimes come up from the region under the Five Shires.
Lastly, the south eastern periphery of the Shadowelves lands reaches the north western corner of Karameikos.
The gnomes of Highforge have an informal secret alliance with the earth-connected creatures which live in this level, cooperating with them to keep humanoids, beholders, hivebroods and deep glaurants at bay. Shadowelves have not many direct connections to this region, so they have only rarely explored it. Some minor trade has occurred and occasionally occurs between the shadowelves, the gnomes and the geonids.

The Middledeep

This region of the Shadowdeep goes down 12 miles from the surface. If it takes just about one day of travel to cross the whole Upperdeep above, it may take up to 15 days to go down to the bottom of the Middledeep, or coming up from its bottom. Generally the inhabitants of this region know of the existence of the surface world, but have escaped or forsaken it and remember it only in their legends, as a cursed and fearful place. They likely will see all travellers as possible invaders, and will try to capture and question them to learn if their lands are in danger.

5th level, Deep Glaurants and Undeads

Between about 5,000 and 10,000 feet beneath ground level, down to 3,000 meters or 2 miles.
Normally about 2 days walk to reach the surface.

The people inhabiting this layer under Karameikos are mostly deep glaurants, in the west and under the Five Shires, and undead in every other direction. The full extension of the territory inhabited by the deep glaurants is unknown, as is their nature and motivations. They are however one of the few creatures of the Middledeep which are known to surface dwellers and occasionally encountered in the Upperdeep of the Five Shires.
This layer of the Middledeep is indeed the one nearest to the surface, and therefore its inhabitants maintain a strained relationship with the surface. If no one knows why deep glaurants sometimes approach it, the undead which inhabit most of this layer under Karameikos were in most case surface dweller during their mortal lives.
Some geonids sages of the level above say the Karameikan region of this layer has some connection to Limbo, and therefore draw undead to it. Other rumours say followers of Nyx, Hel and Thanatos are constantly in battle for the dominance of this region. Few, if any, has ever explored this level and no one so far has been able to map it, but the layer is reputed to be quite cold and dry.

6th level, Caverns of the Pyramids

Between about 3 and 5 miles beneath ground level.
Normally about 3 to 5 days walk to reach the surface.

This layer is almost unknown and unexplored by those living above in the Upperdeep. It is called the “Caverns of the Pyramids” because it has vast caves where such structures have been built. The truth is that this region has several city states founded by descendants of Nithia and Taymora who have adapted to life in the dark. The history of this region has been very unstable, with short living nations unifying vast regions and then crumbling, cities dominated by undead for centuries and crusades against them. Only a few explorers from the level above or below may know the current state of this region and its neighbouring lands. This layer has some water and is less cold than the one above, allowing the growth of some fungi forests.

7th level, Mictlan

Between 6 and 7 miles below ground level.
Normally about 7 days walk to reach the surface.

The people inhabiting this layer are descendants of Azcans, brutemen and humanoids. The place indeed took its name from the Azcan underworld. These people could have been the original founders of the ancient city of Oenkmar and related to the ancient Azcan of the outer world and their descendants, the Intua10. Now they have a dark culture worshipping entropic immortals and undead are common, but the territory is hardly unified under a common rule. Clans of brutemen and humanoids also live here, sometimes cooperating with the Azcan and sometimes fighting them. This layer is cold and dry but has some lakes and fungi forests where spiders and centipedes are quite common.

8th level, Deep Fomor

Between about 8 to 12 miles beneath ground level.
Normally about 10 days walk to reach the surface.

This layer is inhabited by fomorian giants11 and beastmen, partially descended from populations which hid under the earth during the Great Rain of Fire or the Glantrian cataclysm of 1700 BC. The fomorians tried to conquer the whole layer and dominate the beastmen several times, with mixed success. They also have been occasionally attacked by the undead and Azcan above and some other populations of the Lowerdeep below, including deep glaurants. This layer is very hot and humid, with many lava rivers and water lakes, and overgrown fungi forest are commonplace, with many big worms and other great monsters.

The Lowerdeep

This region of the Shadowdeep goes down to almost 50 miles below the surface, which is therefore more a myth than a reality for the inhabitants of this level. They sometimes explore the Middledeep above and the Underdeep below, but rarely reach up to the Upperdeep and above, and they may be completely unaware of the surface.

9th level, Crucotaurs

Approx 15 miles down from ground level.
Normally about 15 days walk to reach the surface.

The inhabitants of this layer are crucotaurs, an ancient breed of gatormen which conquered this layer in ancient times from the original myconid inhabitants. Myconids however are still numerous in the layer and are often allied with lizardmen, troglodytes and caymen, came from above in more recent times, against the dominant crucotaurs. Even if divided in familiar clans, the crucotaurs are quite united against external enemies, and have occasionally attacked both the level above and below. This layer is even more humid than the one above, with less lava and more waterways and lakes, and a lot of fungi forests.

10th level, Saurials

Approx 20 miles down from ground level.
Normally about 20 days walk to reach the surface.

This layer is huge, covering a depth of several miles, and so is really comprised of several different levels inhabited mostly by many different breeds of saurials. Intelligent creatures distantly related to the dinosaurs of the ancient past of Mystara12, saurials are not overly aggressive and have been often menaced by the more warlike crucotaurs above and the cunning amphibians below. Recently, some formian incursions have raided them too. They are trying to create a more unified defensive system to fight back all these enemies. This layer is vast and diverse, but generally less humid than the one above, even if it still has plenty of waterways.

11th level, Amphibians

Approx 25 miles down from ground level.
Normally about 25 days walk to reach the surface.

This layer is again huge and very humid, almost a continuous fungal swamp in all six directions. Frogfolks, intelligent salamanders, newts and other amphibian creatures dwell here, in many different breeds and cultures. Often divided, they have been still quite capable of defending their territories and menacing the layers above and below, until recently. The formian invasion from below is in fact conquering vast lands of their territories, and their resistance is getting more and more desperate, often using artificial floods against the invaders. Such floods have often disastrous consequences both for the invaders and the native populations.

11th level, Therapsids

Approx 30 miles down from ground level.
Normally about 30 days walk to reach the surface.

This layer is inhabited by intelligent therapsids13, ancient creatures which lived in the remote past of Mystara and are now almost completely extinct, if not for some remnant populations in the Hollow World. The group inhabiting this region, adapted to life underground since immemorable times, is now on the verge of extinction too as the formians from the level below have invaded the region and enslaved most of them. Other native intelligent creatures, mostly myconids, have been enslaved by the formians too. This layer is hot but relatively dry, even if there are some waterways and lakes, and several fungi forests.

12th level, Formians

Approx 40 miles down from ground level.
Normally about 40 days walk to reach the surface.

This layer is even bigger than the ones above, covering an extension of ten miles of depth and all the surface of Karameikos above. It is a gigantic ant hill inhabited by formians, who have transformed all the region to suit their needs and are now in the process of invading nearby regions and layers above and below. Once an isolationist and closed society, they have recently become expansionists, enslaving all the creatures they meet. They are not harsh masters but they cannot really understand concepts such as freedom or time off, so living under their yolk is quite difficult. The formians will probably not stop their conquest until they meet an opposition so strong to contain them. Their layer is mostly dry and has some lava river, but their efficiency is so high they can manage perfectly the scarce waters and food of this layer. Still, being the region so huge, there are many wilderlands inhabited by animals, monsters, fire and earth elementals, geonids and myconids.

The Underdeep

Also called The Worlds Below this region of the Shadowdeep is the deepest one, going from 50 to 600 miles down from the surface, thus reaching the World Shield that separates the Outer from the Hollow World. The people inhabiting these regions often do not believe the surface exist, and would laugh at the notion of things such as sky, sun, moon or stars, even if they have a mouth and they can laugh. Indeed most of the inhabitants of the Underdeep would appear quite alien to the people living on the surface.

13th level, Spiders and Scorpions

Approx 50 miles down from ground level.
Normally about 50 days walk to reach the surface.

Unique underground civilization of aranea and manscorpions inhabit this layer, which has arid and humid regions. Enemies for centuries, if not for thousands of years, they have recently found an unlikely unity when the formians from level above invaded their homes in force. Now they are fighting to survive, or at least to remain free, against overwhelming odds.

14th level, Worms, Oozes and Miriapods

Approx 60 miles down from ground level.
Normally about 60 days walk to reach the surface.

The inhabitants of this layer are intelligent worms, slugs, oozes and centipedes14 which have their own culture and strange architectures. Their layer is quite arid, dry and sandy, but they are still very worried by the possible expansion of the Wiassian Empire from the level below and the formians from above. Currently they are aiding the resistance of the araneas and manscorpions above, while also making plans to resist an invasion from below. The native creatures here, despite their alien appearance, are relatively friendly and could become guides and allies for visiting PCs.

15th level, The Wiassian Empire

Approx 75 miles down from ground level.
Normally about 75 days walk to reach the surface.

The Wiassian Empire15 is inhabited mainly by three very different water descended races, one resembling crabs, one manatees and the third knas, but they have not a real relation to these outer world creatures as their ancestors came from the plane of water aeons ago. The Empire now spans a huge underdeep area from below the serpent peninsula to the Alatian islands, from southern Darokin to northern Davania, and has conquered several areas in lower and upper levels too. All this area is partially filled with water, and if the wiassians find an area which isn't, they fill it. Actoians do not know yet that will be their future, but they'll discover it soon enough. For now the Wiassan occupying force has magical devices to breath air in Actoian. The wiassians however do not drown all the air-breathing races, they just modify them to make them able to breath water. Obviously that works best with the second and third generation of the modified specimen, while the first one normally has more difficulties and often die out quickly. That's also for the best as second and third generation subjected people do not remember anymore their original culture and nation. The main result of their great expansion is that the Empire is now the home of a dozen more races that were originally air-breathing creatures, but aren't anymore. The Empire has good relations with other powerful nations of the elemental plane of water but it still has some opposition on its main level as in the Underdeep of Davania there is a powerful nation of lizard-like water beings, to the north and the east there is a strange race of underground amphibious giants and to the west and south west there are Deep Glaurants. Wiassan is an orderly, authoritarian society where the state religion is dominated by Protius and Vanya. There is also an outlawed peace movement lead by the clandestine churches of Koryis, Calitha, Petra and Chardastes.

16th level, Actoian

Approx 80 miles down from ground level.
Normally about 80 days walk to reach the surface.

Actoians are descended from earth creatures of ages past. They resemble dwarves in physical proportions but are tall as humans. An ancient, peaceful nation, they have recently been conquered by the Wiassian water empire from the level above. Many Actoians have come to accept the conquest, but a resistance movement is still active among the younger generations and followers of Maat, in spite of the small chances of success. The known neighbours are several communities of geonids and rockmen to the north and the east, that the Wiassian are trying to conquer too, and deep glaurant to the west. The Actoians sealed all the passages to the west centuries ago to keep the Glaurant away, but the Wiassians do not fear them and are ready to re-open the tunnels to invade these lands too. As explained above, they also plan to open gates to the Plane of Water to make Actoian an underdeep sea as soon as possible.

17th level, Fyarash16

Approx 90 miles down from ground level.
Normally about 90 days walk to reach the surface.

The Melting Tower

When the planet of Mystara was young, it was covered with lava and inhabited by fire creatures. They forged nations and empires that lasted thousands of years, until they were replaced by new races. Many of the fire creatures died, others escaped in their elemental plane. But some stayed. Besieged by their enemies they seek refuge in the only place where only them could live, in the fiery deeps below.

Now entire nations of fire creatures live in the depths, hundreds of miles below the surface, and only rarely they come in contact with the other creatures living above them... But in some places, where hot lava comes to the surface or near to it, they could be encountered...

The Melting Tower is a huge lava shaft near to Karameikos' surface, in an underground area 8 miles northeast of Highforge, that goes down for miles all the way to the World Shield. The shaft is surrounded by intricate passages and tunnels that are the home on the higher levels to lava lizards, fire beetles, lava Oozes and fire fundamentals, but that, going deeper, are inhabited by flame salamanders, elementals, fire drakes and efreets.

The people of the Fire nations however are inside Mystara since so much time that their culture is peculiar and quite different from their brothers in the elemental plane. But to expand on this, I'll go with an In-game POV.

Report to the king of Highforge, prospect squad 12G

We went into the tunnels of the north east as we were commanded. As your majesty knows, the area is full of ancient ruins and dungeons, some dating back to lost giants kingdoms, others to more ancient creatures, others to humans. Yet what we found there is something completely different. We were into a tunnel going deeper and deeper, that we found had more and more metal ores as we descended. At the beginning the tunnels were dark and cold as expected, and we encountered only harmless small animals and insects, until we began to see a dim red light ahead of us.

Wary and prepared we went forward until we found a cave lit by small pools of melted lava. This was revealed as a rather large area, also rich in minerals and gems, that continued for several caves and tunnels. Many were inhabited by lava lizards, fire beetles and little elemental creatures that posed no threat to us as they just fled our approach. Onwards we went until we saw something bigger coming toward us. We were ready for the worst when we realized that the approaching creature was clearly a flame salamander. And we were astonished when she, as we later learned, made peaceful gestures and tried to speak to us. We managed to communicate only with magical means, as her language is unintelligible and sounds like crackling fire. The salamander told us that we were near to the entrance of the Fire nations, inhabited by thousands of fire creature that live below the earth, right below us. She said that many of them would be happy, like she was, to communicate and trade with people from the Air kingdoms, as she called our lands. But the most wonderful view was yet to come, because as we spoke with her we went forward and suddenly we came out of the lava tunnels into a great rock ledge that overlooked what I could only describe as a huge lava shaft, lit by fire, that went below into the depths of the earth as far as the eye can see.

And in the middle of the great shaft, that I think was at least 600 feet across or more, there was a flying vessel kept aloft probably by hot air, not unlike our balloons. In the vessel there were other creatures. Some were flame salamanders, as the one that was speaking with us, others were more similar to us, they looked like slightly taller gnomes, shorter than humans, with braided beards and hairs that seemed on fire. Others yet looked like giants, taller than humans, and had no bears nor hair. We were indeed very intrigued by these people, but we thought it was best to return to Highforge and report this amazing encounter, even if the Flame salamander, she gave her name as Shal'iass or something similar, invited us to enter the vessel and come down to visit their realms. We just said her we would return, and she let us go without hostility. I believe it is now up to your majesty and the elders to decide if and when to contact these creatures again...

Fyarash is the land of the Fire Nations encountered by the gnomish prospect squad above. The intelligent races that live in this area are a sort of flame salamanders, fire drakes and two species of elementals that looks a bit like tall gnomes and short hill giants. The latter two are visually similar to humanoids but are not, indeed they are ovoviviparous just like the salamanders and their newborns must stay several days in very hot pools of sulfuric waters. Normal water and cold are instead harmful to them. Fyarash is a great area of tunnels, huge caves, lava rivers and lakes with town and cities and around 90.000 inhabitants. The origin of the fire people date back to very ancient times, when fire elemental creatures inhabited the surface of Mystara. Defeated by air and cold creatures, they sought refuge below the earth and have lived there ever since. In so many years they have lost any connection with the elemental plane of fire. Indeed invaders from the plane were defeated by the fire people several times in their history. They do not know the truth about the Deep Black level below them, nor they know of the Fire Pit (that would bother them much) but thanks to the Melting Tower they do know of several levels above them and of the surface, that they call the air kingdom, thinking it is still under the rule of the dangerous and hated air creatures.
They had some sporadic clash with the earth people directly above them but they do not know of the main menace to their land, the powerful Water empire that's spreading just two levels above.
They have other neighbours on their same level: to their south there is the Great Lava Sea dotted by the islands of the Fire drakes, peaceful nations with whom they trade. To the east there is the realm of the Fire Giants, kin to the same people who inhabit Fyarash and usually peaceful. To the north there is the so called Efreet Dominancy, a nation of renegades who left the plane of fire centuries ago and who the Fyarashians mistrust. To the east there is the hated dominion of the Deep Glaurants, with whom the Fyarashians fought innumerable wars...

Fyarash politics and society

Fyarashian are, predictably, fiery people, divided on many issue in religious and political factions. The factions are always engaged in heated debates that usually do not escalate in open battles, but often results in bloody duels. There is an atheist faction, one that serves an ancient fire dragon and factions of Ixion, Zugzul, Rathanos, Pflarr, Tarastia, Fire Elemaster and others...
Another major cause of duels in Fyarashian society is romance, a fundamental part of life for the many hot blooded youngsters.
Factions sometimes cooperate, but more often divide families, marriages and cities. Against outside aggression however Fyarashian have always been able to unite, yet a very powerful enemy could exploit their division to its gain.

The Far Underdeep

The deepest regions of the Underdeep are so remote and dangerous that even the inhabitants of the layers above speak of them as legendary dangerous locations. The inhabitants of these deep layers are often strange and terrible.

18th level, The Deep Black

Between about 100 to 200 miles below the surface.
Normally about a 100-200 days walk to reach the surface.

This pitch dark area is inhabited by the ancient dragon Mahandrahyax, who in ages past fought against the Immortals and was blinded. Mahandrahyax is an earth dragon, an extinct breed, much larger than modern dragons, wingless and grey, with incredible elemental powers. He sleeps most of the time, but rarely he wakes up and scream his pain and rage, an appalling sound that travels for many miles in the tunnels. The area is also strangely devoid of lava and seismic activity but every two days, for unknown reasons, a strong wind blows, creating other strange, eerie sounds. The Deep Black can be crossed in 20 disquieting days. This enormous region probably contains many other inhabitants, normal animals and monsters, but apparently not intelligent beings. The inhabitants of Fyarash above fear this region and avoid it, and have sealed most of the tunnels leading down.

19th level, The Moving Earth

Between about 200 to 250 miles below the surface.
Normally about a 200-250 days walk to reach the surface.

The main inhabitants of this huge level are Earthquake Beetles and other giant insects and worms. This area of the underdeep is literally moving and has constant landslide and lava explosions. It's also inhabited by several lava creatures. It could be crossed in 10-20 days but managing to escape it alive it's not an easy feat.

20th level, The Maze of Madness

Between about 300 to 500 miles below the surface.
Normally about a 300-500 days walk to reach the surface.

That's a huge multi-level than include dormant burrowers and several other aberrations, like beholders, illithids, chokers, chuuls, demons, otyughs, lesser outer beings, giant worms, athachs, nekrozons, dusanus, brain collectors, hook horrors, ropers, undeads of forgotten ages and other nasty things. This pitch dark and terrifying area has several planar gates but is not easily connected with below and above levels, yet it could be eventually crossed through difficult passages in 40-80 days going down, double time going up. And those would be quite interesting months for a group of PCs.

21th level, The Fire Pit

From about 550 to 750 miles below the surface.
Normally about a 550-750 days walk to reach the surface.

This level is a permanent gate to the elemental plane of Fire, and it's connected to other huge lava lakes/environments that leads to the same plane deep below Ylauruam, the Northern Reaches and Norwold. It's not connected however in any way with the surface, nor with the levels above. This place has existed for billions of years and it has been occupied and inhabited by several fire creatures, from elementals to elions. Now the Efreeti Empire rules here, has recently discovered the World Shield and it's slowly digging its way around, up and down, searching for inhabited areas and treasures. They could be quite far from the surface, but they have a sort of connection with it since the Karameikos school of Magecraft17 opened in Krakatos the so-called "Elemental tavern" a room within the school where teacher and students can peacefully meet outsider creatures, like elementals. Recently an efreeti agent of the Empire visited the place in disguise, and his masters could decide the idea could be useful to visit the surface areas in force...

The World Shield

This region of reversing gravity divides the Outer World from the Hollow World. As we do know from the Hollow World Boxed Set that several group of elves travelled all the way to the Hollow World, they must have found a mean to go beyond it.
The effect could be similar to the gravity flutes described in Gazetteer 13 The Shadow Elves, only much bigger, and so particular expedients may be needed in the regions where the “wall” becomes the “floor”.

The Hollowdeep

The Shadowdeep going from the World Shield to the Hollow World will be described here in less details than the layers above. The Hollowdeep however should also contain more than 20 different layers, or more, as the Shadowdeep regions described above.
The Hollowdeep normally contains “experiments”, i.e. races that were placed in the Hollow World by the Immortals, but were later removed from the surface, usually because they were corrupted by Burrowers, or by entropic immortals, or because something is very wrong with them. Therefore the intelligent creatures that inhabit the Hollowdeep are normally scary, mad, cursed or all these things together. The Hollowdeep could be indeed considered the entropic idea of the Hollow World.

The Burrowdeep

Between about 100 to 750 miles below the Hollow World surface, or 800-1,500 miles from the Outer World surface.
Normally about from 100 to 800 days walk to reach the Hollow World surface and 800 to 1,500 days to reach the Outer World surface

This level is inhabited by what’s left of the Burrowers18, the great worms and monsters that almost destroyed the Hollow World in ages past. Most of them are in deep slumber now, but from time to time one awakes, provoking earthquakes under the earth, or two may awake and begin fighting each other directly or through proxies. Many aberrations and other monsters also inhabit this layers, together with some intelligent servants of the Burrowers, such as corrupted beastmen and deep glaurants. From time to time they may be able to attack nearby layers, or even layers and levels quite far away from them. Outer Beings servitors19 and followers of Thanatos and other entropic immortals can also be found in this region.

The Lower Hollowdeep

Between about 50 to 100 miles below the Hollow World surface, or 1,500-1,550 miles from the Outer World surface.
Normally about from 50 to 100 days walk to reach the Hollow World surface and more than 1,500 days to reach the Outer World surface.

This big region of the Hollowdeep is inhabited by very ancient races, some of them present also in the surface of the Hollow World or in the Shadowdeep of the Outer World, such as aranea, manscorpions, hivebroods, formians, other intelligent insects, myconid and other intelligent fungi, intelligent oozes and worms such as scamilles and wurmlings, decapus, geonids and rockmen. The main difference between those living in this region of the Hollowdeep and those living on the Hollow World surface or the Outer World is that usually the populations in the Hollowdeep have something “wrong” which prevented them from living under the red sun below, or the yellow sun above.
They may be infected with some sort of undeath or lycanthropy, cursed or corrupted by the Burrowers, followers of entropic immortals or something else entirely. Needless to say, most of these populations are not the friendliest around in Mystara, and PCs travelling through their territories should take extra care, or avoid them.

The Middle Hollowdeep

Between about 15 to 50 miles below the Hollow World surface, or 1,550-1,585 miles from the Outer World surface.
Normally about 15 to 50 days walk to reach the Hollow World surface and more than 1,550 days to reach the Outer World surface.

This region of the Hollowdeep is mostly inhabited by intelligent saurials, amphibians, therapsids, lizardmen, troglodytes, gatormen and other reptilian creatures. As said for the previous region, all these people have something “wrong”, or are tainted by Outer Beings, burrowers, entropic immortals or all of them. Some high carnifex and Y’hog carnifex20 escaped from immortal purges are hidden in this region too, and should they be able to conquer vast territory or reach one of the surface the danger they pose could well put all Mystara on the verge of destruction.

The Upper Hollowdeep

Up to about 15 miles beneath the Hollow World surface, or 1,585-1,600 miles from the Outer World surface.
Normally about from 15 days to an hour walk to reach the Hollow World surface and 1,600 days to reach the Outer World surface.

The Upper Hollowdeep is a very diverse region with many different inhabitants. The lower levels (those farthest from the Hollow World surface) are normally inhabited by demianimals21, but the populations living far from the red sun, differently from their cousins on the surface, are generally in some way corrupted by Entropy. The upper levels, nearest to the surface, are inhabited by the Shattenalfen, Intuans22, Bahlorian undead23, followers of Nyx24, mummies25 and many other, often human-like, creatures who prefer darkness to light. All these people are more often hostile to traveller than not, and PCs passing through their domains will risk becoming food or sacrifices if captured alive.

1This name was chosen by the Mystara community in a series of past discussions partially available here: due to the fact that the Shadowlands inhabited by the Shadow elves described in Gazetteer 13, see here:, are the primary source on Mystara’s underworld.

2The original Wizards board links included are now dead, but have been preserved here, as discovered by Havard:
Canonical name for Mystara’s Underdark:
NPCs of the Shadowdeep:

Races of the Shadowdeep:

Regions of the Shadowdeep:

Prestige Classes:

Magic of Anwn:

3This is my calculation assuming Mystara with dimensions similar to the Earth and the Hollow World dimensions as supposed by me in Threshold issue #9, see also here: for my suppositions on the dimensions of Mystara. The Hollow World boxed set assumed a smaller Mystara, and so the distance was said to be “only” 1,200 miles. Thorfinn Tait on his calculations assumed instead a Mystara roughly as big as Earth, but the Hollow World more or less with the dimensions estimated in canon sources, so his distance is about 2,000 miles, see here:

4As mentioned in the above threads by Cthulhudrew, see also the module DDA1 Arena of Thyatis.

5Which on mountains could be quite over sea level, even if underground.

6See the article on Elegy Island by Giampaolo Agosta in issue #13 of Threshold magazine or the articles on Koskatep for more information about these special undead and the church.

7See the work done by Giampaolo Agosta on this, stored in the Vaults of Pandius here

8See my article The Darkness Beneath, Ancient buried secrets in the Sea of Dread, in Threshold issue #3: and the extended material on Taymora in Threshold issue #12.

9A hivebrood nest under Specularum appears in the adventure “Of Nests and Nations” published in Dungeon Magazine #13.

10See Threshold issue #12 and the 2300 BC setting by John Calvin about the past of the Known World, stored here in the Vaults of Pandius:

11Inspired by this article by Giampaolo Agosta in the Vaults of Pandius and by later development by me and John Calvin in the 2300 BC setting and Threshold issue #12.

12Saurials are just the Mystaran version of the same creatures which appeared in the Forgotten Realms setting I imagined some populations of them still living on the surface in Davania and the Hollow World, see also Threshold issue #5 and #9.

13Therapsids are the ancestors of mammals: In Threshold issue #9 I imagined some of them in the Hollow World.

14Creatures such as the canon Scamille ( and Wurmlings (

15This level and the ones below are already stored in the Vaults of Pandius here as I described them some time ago.

16Fyarash was detailed much more of the other layers, as you can see in the original link of note 14. I have replicated the longer description here as an example of a partial development of such a Shadowdeep layer.

17Founded in 1010 AC in the Poor Wizard Almanac.

18Ideas proposed mostly by Andrew Theisen and others here in this thread at The Piazza:

19See this article by Geoff Gander here on the Vaults of Pandius and more work done by him on the subject here

20See the work done by Geoff Gander here on the Vaults of Pandius and in several more articles.

21The races of anthropomorphic animals, a neologism created by me in assonance with demihumans in Threshold issue #9.

22See the 2300 BC setting by John Calvin stored in the Vaults of Pandius here and Threshold issue #9 about Intua and its presence near Oltec lands in the Hollow World.

23The Empire of Bahlor would be a version of Taymora preserved in the Hollow World east of Milenia, as imagined by Havard here and James Mishler here in the Vault of Pandius

24Under the Mileanian Empire, where Nyx is called Zargos, see also HWR3 The Milenian Empire.

25Under Nithia, see also HWR2 Kingdom of Nithia