Plane of Earth

Earth is a fundamental component of the multiverse and perhaps the most visible to most inhabitants of the Material Planes. Continents, islands, mountains, hills – these are all concrete examples of this ubiquitous element across the realms, and it shows up in all of the other Inner Planes as well in one form or another. And the root for all that rock and dirt is the Plane of Earth.
Much of this plane is solid mass making it difficult for non-native creatures to move around or even breathe. However, limitless tunnels, passages, and caves wind their way through the stony realm, the result of both incursions from other Inner Planes and determined digging efforts by the native creatures.
Getting lost in the Plane of Earth is perhaps the greatest threat to travelers beyond a collapsing tunnel or marauding beast as there is no clear indication of any cardinal direction. Tunnels wind up and down, cross between each other, and cut into massive caves with no discernable pattern or thought. For travelers willing to risk the journey, however, great treasures and wonders can be found, whether it’s the secret at the center of the Deep Crystal Labyrinth or searching the chaotic Tunnels of Madness for the Heart of All Mountains.

GETTING THERE

In the Material Plane, natural gates and portals have been known to appear in the deepest mines dug by dwarves. Many dwarven strongholds consider themselves the first line of defense against incursions from the Plane of Earth, whether it be by natural monsters or planned invasions by the gargoyles. Some deeper dungeons in the Material Plane have been known to contain gates to the Plane of Earth as well, whether stumbled upon accidentally or deliberately opened by wizards and priests eager to use earth elemental creatures as guardians and workers.

Geography

LAY OF THE LAND

The Plane of Earth is best described as the largest chain of mountains in the multiverse both in height and breadth. For those brave or foolish enough to try and reach the top, they find only the Void Peaks – the mountain tops pierce a veil of airless black that is inhospitable to living creatures. Most planar scholars agree that the Void Peaks are a breach from the Plane of Earth into the Negative Plane, the multiverse source of death and decay that enfolds all of the realms.

Below the Void Peaks and encompassing the vast majority of the Plane of Earth is the Stony Expanse. Great veins of minerals and rich ore cut through the rocky layers of the Stony Expanse and over the countless centuries tunnels and caves have been carved out by time or force.

Beyond the Stony Expanse, where the Plane of Earth approaches the other Inner Planes, the region becomes more diverse. The Mud Hills are a vast region of bubbling, chur-ning dirt and muck close to the Plane of Water – between the two sits the distinct Swamp of Oblivion (also known as the Plane of Ooze). The Mud Hills are open to the sky and the tunnels that cross beneath are treacherous and prone to constant shifting at a moment’s notice, so most travelers avoid this region entirely. It is known that the gargoyles have several outposts in the Mud Hills to search for rare mineral deposits that are known to show up only in that area.

The heat intensifies on the other side of the Plane of Earth in a region known as the Furnaces, close to the Plane of Fire. Lava seeps up and creates dangerous terrain, but the dao have harnessed the raw potential of the Furnaces to power their forges.

Ecosystem

Highlights & Impressions

The below listings include notes on highlighting the nature of the Plane of Earth as characters explore and travel through it. These are suggestions of elements that can be used in descriptions of the landscape and denizens with the goal of actualizing the “outside” nature of the multiverse beyond the Material Plane. Use them to incorporate into encounters and adventures on the Plane of Earth.
Cave After Cave. The Plane of Earth is a titanic sprawling complex of tunnels and caves created both from natural effects and deliberate hands. The caves are filled with stalactites and stalagmites, though water is a rare sight – what then creates these natural formations? No one knows the answers for sure, and most simply believe they rise and fall from the will of the plane itself. Any cave feature in the Material Plane can be found on the Plane of Earth even if it has no logical explanation.
Strange Sounds. Sound travels strangely in the endless underground of the Plane of Earth. Echoes bounce around expansive natural caves, distorting wildly before traveling down tunnels miles away from their original source. Drips, drops, cracks, groans, crashes, collapses, and more all can be heard at times, some close by while others far away.
Stagnant Air. The incredible weight of limitless rock and stone stifles the very air. Earth and air are diametrically opposed elements, and perhaps because of this the breathable air in the Plane of Air is stale and stagnant at most times. It’s usually not hostile enough to cause problems but it’s definitely something travelers notice immediately upon arrival. Even in the largest caves, such as the Great Dismal Delve, the air carries a foul taste noticeable to outsiders.

Ecosystem Cycles

CYCLE OF TIME

There is no natural way to tell time across the Plane of Earth. Even the Void Peaks have no sun to mark the days, though the Mud Hills are lit by a dim pale light that darkens slightly every twelve hours. This lack of time and the general closeness of the tunnels in the Stony Expanse leads many travelers to madness and despair.

However, the gargoyles have developed a way of telling time. Each outpost and most buildings are furnished with a clock gem, an enchanted jewel of nearly any size that changes color gradually from red to blue and back again to mark the passage of time. Unfortunately for travelers used to the cycle of time in most Material Planes, the clock gems are based on a 13-hour cycle (13 hours of red time followed by 13 hours of blue time) creating a 26-hour day.

Localized Phenomena

HAZARDS & PHENOMENA

The Plane of Earth holds numerous threats to travelers beyond its lack of breathable air for most of the realm. From collapsing tunnels to falling rocks and flows of magma and ooze, the plane holds no small amount of danger for the unprepared.
Earthquake Despite its reputation, the Plane of Earth is constantly in motion. Normally this motion is slow and grinding, but occasionally it is sudden and dangerous. When an earthquake occurs, it strikes in a 100-foot-radius centered on a random nearby point to the party. For 1d10 rounds, the area is struck by the effects of the earthquake spell, which has the following additional effect. The below effect occurs with any casting of the earthquake spell as well.

Every round, rocks and debris rain down from the ceiling unless the area has been specially fortified against such events (most gargoyle settlements are protected by earth magic against the effects of the planar earthquakes). At the end of every creature’s turn in the radius of the earthquake they must make a DC 14 Dexterity saving throw, suffering 14 (4d6) bludgeoning damage on a failure, or half as much on a successful save.

There is a 10% chance per round of the earthquake that a collapse occurs across the entire area of effect. See below for the results of a collapse.

Collapse The Plane of Earth is treacherous to the unwary and it can bury travelers in a moment’s notice. A collapse occurs when something causes the ceiling of the tunnel or cave to crumble, sending rocks and debris crashing down in a heap of rubble. Most collapses occur in a 30-foot-radius, though collapses caused by an earthquake fill a much larger area.

When a collapse occurs, roll on the below table to determine the type of earth that fills the area. Creatures in the collapsed area must make a DC 15 Dexterity saving throw, suffering the listed bludgeoning damage on a failure along with being completely buried. A successful save results in only half damage along with being restrained by the rubble.

1d10 Type of Earth Damage

• 1-3 Soil 14 (4d6)
• 4-6 Very soft rock 21 (6d6)
• 7-8 Soft rock 28 (8d6)
• 9 Hard rock 35 (10d6)
• 10 Very hard rock 52 (15d6) Creatures buried must dig their way out using the digging guidelines in the Traveling Around section, and they are buried beneath 1d10 feet of earth. Suffocation begins immediately unless the character can hold their breath or otherwise function without breathing. A character that is only restrained by the rubble can remove themselves with an action to make a Strength (Athletics) check against the digging DC of the earth type restraining them.

When a collapse occurs, roll for a random encounter to see what else might come through as a result of the opening. After a collapse the area is considered difficult terrain for movement purposes.

Ooze Flow Some large swaths of the Plane of Earth have mixed with moisture from the Plane of Water to create dangerous ooze flows. These are common in the area below the Mud Flats, but any portion of the plane can contain a planar vortex to the watery realm.

Ooze flows contain dangerous levels of acid and spread out to fill a 100-foot-radius area, or whatever equivalent open area exists. Every round a creature is in an ooze flow they must make a DC 14 Constitution saving throw, suffering 13 (3d8) acid damage on failure, or half as much on a successful save. Ooze flows are normally only 2 feet deep. The affected area is considered difficult terrain and the ooze flow remains until released by a collapse or earthquake.

Magma River Similar to an ooze flow, a magma river is an incredibly hot flow of earthen material mixed with elements from the Plane of Fire. The Furnaces are filled with magma rivers, which cut great swaths through the caverns in that region of the plane, but they are not unheard of across the Stony Expanse.

A magma river is normally 20-feet wide by 200-feet long and pours into any open space, where it pools for a time before collapsing the earth below it and flowing out of the area. Any creature that starts its turn in a magma river must make a DC 14 Constitution saving throw, suffering 22 (4d10) fire damage on a failure, or half as much on a successful save. A magma river is normally 5 feet deep, but this can be raised depending on the area in which it flows into.

Pulse Crystals Pulse crystals are normally found in clusters of 3d6, and each crystal is 7 to 10 feet tall. They occur naturally where vortexes exist between the Plane of Earth and the Positive Energy Plane – most planar scholars believe them to be extensions of one of the quasi-elemental planes that are theorized to exist close to the energy planes. Whatever their origin, they are welcome respite for travelers, especially those not used to underground living.

Each pulse crystal glows with dim light in a 20-footradius of a random color, shifting every hour or so between green, red, blue, and yellow. Some planar predators know to seek out and hang around clusters of pulse crystals, as many creatures are drawn instinctively towards the lights.

Rock Rot Some sections of the Plane of Earth are infested with microscopic pests known as mineralmites. They are not harmful to living creatures not made out of stone as they feast on the rich internal consistency of rock and stone. As they do so they pass through it, leaving the area chalky and unstable. Dwarves and gnomes are familiar with the resulting rock rot as the mineralmites are not uncommon outside the Plane of Earth as well.

A floor infested with rock rot can be spotted by a dwarf or native earth creature with a passive Perception of 13 or higher, or by any other creature with a passive Perception of 16 or higher. The rock rot infested area is brittle, and crossing them requires a DC 14 Dexterity (Acrobatics) check. Characters unaware of the presence of rock rot suffer disadvantage on the roll. Failing the result sends the character plummeting through the hole down a distance of 1d10 x 5 feet. An area infested with rock rot extends out to a radius of 50 feet.

Random Encounter Tables The below table can be used by the Dungeon Master as a source of inspiration when a party of characters is traveling around the Plane of Earth.

1d100 Plane of Earth Encounter

• 01-05 Hostile earth elementals
• 06-10 Some hungry xorn
• 11-15 A pack of earth weirds
• 16-20 A mining crew of gargoyles
• 21-25 Gargoyle cultists of Orthaeus
• 26-30 A pack of basilisks
• 31-35 A lone greater basilisk
• 36-40 Ropers
• 41-45 A wave of creeping stone
• 46-50 Sandmen controlled by Skatha
• 51-55 An ancient gargoyle assassin stalking a target
• 56-60 A succubus artist and a group of charmed art slaves
• 61-65 A group of galeb duhr
• 66-70 A zaratan
• 71-75 Rock rot
• 76-80 Pulse crystals
• 81-85 Magma river
• 86-90 Ooze flow
• 91-95 Collapse
• 96-99 Earthquake
• 00 Ghost Tunnels

Tourism

SURVIVING The tunnels and passages that cut through the Plane of Earth are breathable, so one of the greatest threats to travelers are cave-ins and earthquakes that can suddenly send tons of rocks crashing down. Digging out of such a burial can be dangerous depending on the type of earth involved (see the Hazards & Phenomena section for details).
Fresh water is scarce and edible food for non-natives can be hard to come by, so travelers are encouraged to have a source of sustenance before venturing out into the Stony Expanse.
In the Void Peaks, there is no air so anyone that penetrates the surface of the Plane of Earth here begins suffocating immediately unless they hold their breath (or do not need to breathe). The closer a traveler gets to the Void Peaks, the less air is available so ascending to this region is not advisable.

TRAVELING AROUND Once a traveler reaches a cave or tunnel in the Plane of Earth, moving around becomes as easy as following a pass-age – and as frustrating when that tunnel leads to nowhere! Most native creatures, such as the xorn and earth elementals, can move through the earth of the plane as easy as a fish moves through water, leaving no tunnel in their wake.
Powerful magic can allow an adventuring group to do the same, but for most the zigzagging passages that cut through the Stony Expanse are the most accessible means of transportation.
Many of the tunnels do connect to other regions, owed in large part to the never-ending machinations of the gargoyles. They constantly hunt for greater sources of ore and gems and use teams of slaves to accomplish this, but moving so many creatures across the Plane of Earth can be difficult.
Digging around the Plane of Earth can become a necessity for travelers, especially if they’ve been trapped in a cave-in or earthquake. You can use the below table to determine randomly what kind of earth is being dug through, which determines the progress and difficulty of the digging.
1d10 Type of Earth DC Progress Per 10 Minutes 1-3 Soil 12 10 feet 4-6 Very soft rock 14 5 feet 7-8 Soft rock 16 4 feet 9 Hard rock 18 2 feet 10 Very hard rock 20 1 foot
Digging is a Strength-based ability check. Using and being proficient with mining tools adds a user’s proficiency modifier to digging checks. Other characters can assist with the Help action under the appropriate circumstances.

Type

Dimensional plane

Location under

Inner Planes

Related Reports (Primary)

• Session 075: Elemental Evil Prince of Earth, Part 1 Report