World Tree cosmology

The World Tree cosmology model was outlined in the Year of Wild Magic, 1372 DR, and quickly became the most widely accepted model during those tumultuous times, supplanting the Great Wheel cosmology. The name came from the discovery of a sentient being that manifested itself as a brobdingnagian tree that connected various planes of existence, much like the river Styx. The World Tree cosmological model was invalidated by the Spellplague in 1385 DR and the decade that followed, during which the Elemental Planes collapsed into the Elemental Chaos, the Ethereal Plane and World Tree were destroyed, and the Outer Planes that survived became drifting dominions in the Astral Sea as described by the World Tree model's successor, the World Axis cosmology model.

Basic Structure
The Inner Planes, also known as the Elemental Planes plus the Energy Planes, made the transition from the Great Wheel model to the World Tree model almost intact, the major difference being that they were connected to the Prime Material Plane via the Astral Plane instead of the Ethereal Plane. The Outer Planes underwent extensive rearrangement, increasing in number from seventeen to twenty one to twenty six, and severing nearly all interplanar connections except those to the Prime. Thus the connection map could be said to resemble a tree, with the Prime Material Plane being the trunk with roots "descending" to the Inner Planes and branches "ascending" to the Outer Planes. No longer arranged strictly by alignment, the Outer Planes were grouped into three categories based on being predominantly Good, Neutral, or Evil, regardless of the influences of Law or Chaos. The three categories were the Celestial Planes (good), Neutral Planes (neutral or unaligned), and the Fiendish Planes (evil).

Two more planes were discovered that also connected to all the Outer Planes: Cynosure and the Fugue Plane. Only deities could pass through the astral portals from their realms to Cynosure and back to their home plane. The Fugue Plane was where the souls and spirits of the dead congregated, awaiting judgment or transport to the domain of their primary deity. Only divine, demonic, or devilish servants of the gods could use the portal from their realm to the Fugue Plane for the purpose of guiding, stealing, or bargaining with souls to take them back to their eternal reward or damnation.

The Plane of Shadow was upgraded from a demiplane to be coexistent with the Prime Material Plane, touching it at all points just like the Ethereal Plane, allowing rapid travel between distant destinations on the Prime. It was believed that the Shadow Plane also connected the Prime to other Material Planes, such as Oerth for example.

An adventurer's journey to another plane of existence was typically accomplished by means of an astral projection, plane shift, or gate spell. Astral projection was considered the safest mode of exploring because one's physical body was left behind in a (hopefully) protected location while their astral self traveled through the mostly barren Astral Plane to a color pool that was the door to their destination. Upon arrival, a new physical body was formed out of the materials of the destination plane and this new body was therefore immune to any pervasive environmental hazards. (On the Elemental Plane of Fire a body might be formed out of elemental fire, magma, and brimstone, for example.) In contrast, gate and plane shift transported one's body and possessions directly into possible peril.

Travel between one Inner or Outer Plane and another without passing through the Material Plane was either difficult and dangerous or impossible without involving the mercurial gods and their servants. Deities could maintain astral portals between their realms and those of other agreeable powers, but these were usually not for mortals to use. Two cross-planar features existed that could be used to journey between some of the Outer Planes. First was the World Tree itself, a sentient "tree" on a cosmic scale that joined all of the Celestial Planes together, much like Yggdrasil the World Ash connected Gladsheim to Hades in the Great Wheel cosmology model. The World Tree did not tolerate intruders unless they had a good and noble reason for using it as a celestial shortcut. The other feature was the River of Blood which coursed through all the Fiendish Planes except for the Supreme Throne and the Demonweb Pits in a fashion similar to the river Styx which flowed through all of the Lower Planes in the Great Wheel model. All manner of evil creatures swam in the river, lurked on the banks, piloted craft on the surface, or patrolled the skies above the River of Blood looking to catch anyone brave or foolish enough to navigate the deceptively smooth waters. And just like the Styx, any mortal immersed in the river immediately lost all memories.

Coterminous, Coexistent and Transitive Planes
Coterminous planes were linked at one or more points where travelers could cross over without the aid of magic. Two or more planes were coexistent if they overlapped completely, allowing movement by some (usually magical) means from one to the other at any point. They were also sometimes referred to as parallel planes. Transitive planes were simply used as a conduit or passageway between two planes (or two points on the same plane) that were each coterminous with the transitive plane. A plane could be both coexistent and transitive.


 * Astral Plane
 * The Astral Plane was a transitive plane that was coterminous with all the known planes in the cosmology except for Cynosure and the Fugue Plane. However, in this cosmology model, the Astral Plane was a channeled transitive plane, meaning that once a traveler set out for a particular destination plane, only color pools for that destination were visible to and usable by the traveler. In addition, all branches of the tree-shaped Astral Plane only led to or from the Prime Material Plane&mdash;all Astral travel between any two Inner or Outer planes had to pass through the Prime. The plane itself was a silvery, timeless, weightless void with very little solid matter. Color pools were suspended disks of whatever color matched the chosen destination. Githyanki pirates were known to prey on the unwary.


 * Ethereal Plane
 * The Ethereal Plane was coexistent with the Prime Material Plane, touching it at every point. Magic spells, such as etherealness and ethereal jaunt could be used to phase out of the Material Plane and into the Ethereal. Once there, a traveler could still dimly see the Material Plane as if through warped glass but could move through solid objects and "fly" in any direction just by choosing to do so. The atmosphere was breathable but misty and full of billowing clouds of multicolored fog. Beings on the Material Plane could not normally see travelers on the Ethereal, but if magical means were found to target ethereal creatures then attacks such as magic missile could be used. The reverse was not true&mdash;ethereal travelers could not magically attack beings on the Material Plane. The Ethereal Plane was destroyed during the Spellplague.


 * Plane of Shadow
 * The Shadow Plane coexisted with the Material Plane and could be used as a transitive plane for rapidly traveling long distances between points on the Prime. It was also the link between alternate universes such as Oerth. No connections existed between the Plane of Shadow and the Ethereal Plane, even though they both coexisted with the Prime. Casting the shadow walk spell allowed a traveler to enter the Shadow Plane and move about at the same rapid pace regardless of their normal movement rate, mounted, flying, or on foot. Landmarks were almost useless on this plane because not only could the shadow substance be manipulated by use of shadow conjuration and shadow evocation spells, but the plane itself morphed over time. Mask, the so-called Lord of Shadows, had a castle built of shadow somewhere on this plane. The goddess Shar resided in a solitary tower here also. The presence of these two deities gave the Plane of Shadow some of the characteristics of an Outer Plane. After the Spellplague, Shar managed to weave some essence of death from the Negative Energy plane into the Plane of Shadow and created the Shadowfell.

Outer Planes
The terms Inner and Outer Planes originated with the Great Wheel cosmology model when the structure of the cosmos was seen as a series of somewhat concentric spheres and the names continued to be used in the World Tree model. The Outer Planes were divided into three distinct groups mainly based on the Good, Evil, or Neutral alignment of their inhabitants. Some of the Outer Planes had multiple layers that were coterminous with their neighboring layers, usually at very high or very low elevations giving the impression that they were stacked like tiers. The Astral Plane connected to all layers of a plane if there was more than one (however, see House of the Triad and Nine Hells below), whereas the plane shift spell always targeted the first layer of the destination plane.

Celestial Planes
The Celestial Planes were the home of deities and beings that were fundamentally Good in nature, word, and deed. Each of the Celestial Planes were connected to the Prime Material Plane by a branch of the Astral Plane. Additionally, each of them was coterminous with at least one "neighbor" via the World Tree, which could be used as a "back staircase" with the Tree's permission or tolerance. The roots reached into Arvandor and Dwarfhome from the trunk which touched Brightwater, the Golden Hills, and the House of Knowledge. Extending from the trunk were branches to Dweomerheart, the House of the Triad and Green Fields with the top of the Tree terminating in the Gates of the Moon.


 * Arvandor
 * Formerly known as Olympus in the Great Wheel model, Arvandor was the home of the Seldarine and their cousin drow goddess Eilistraee before her death. Arvandor was filled with natural beauty: a druid's paradise. Known portals included passages to Brightwater, Dragon Eyrie, the House of Nature, and the Gates of the Moon.


 * Brightwater
 * Brightwater was the home plane of Lliira, Sharess, Sune, Tymora and Waukeen. Similar in beauty to Arvandor but less wild and more gentrified, Brightwater was a thriving community full of revelry and rollicking fun. Connections were known to exist between this plane and Arvandor, Green Fields, and Heliopolis.


 * Dwarfhome
 * Dwarfhome was the home of the Morndinsamman, except for the exiled Deep Duerra and Laduguer. Dwarfhome consisted of one mountain big enough to swallow worlds and a smaller second peak called Mount Clangeddin, both of which were full of industrious activity, expert craftsmanship, and astounding artistry. No portals were known to exist on this plane.


 * Dweomerheart
 * A beautiful city with structures only magic could create, Dweomerheart sat on the highest plateau above a warren of caves, caverns, and more plateaus, appearing like a shining university for the study of magic. Mystra and Azuth, as well as their subordinates Savras and Velsharoon, made their home here. No known portals to this plane existed, requiring visitors to travel astrally or successfully placate the World Tree for passage.


 * Gates of the Moon
 * Selûne was the primary resident of this plane at the top of the World Tree, along with Finder Wyvernspur and Shaundakul. A sea of iridescent water surrounded a stony island mountain topped by Selûne's silver palace, all bathed in perpetual moonlight. One portal to Arvandor was kept here by some eladrin but no others were known. However, the mysterious Infinite Staircase would appear during the full moon and was rumored to connect Selûne's realm to every city on every plane.


 * Golden Hills
 * Seven bucolic hills formed this plane, each one the home of a member of the gnomish pantheon. The only member not present was Urdlen who was allowed to live in Hammergrim. Everything on this plane was either a golden hue or tinted, highlighted, adorned, trimmed, or plated with gold. The only known portal in the Golden Hills connected to Gond's realm in the House of Knowledge.


 * Green Fields
 * Very similar to the Golden Hills except more natural colors and cultivated fields, this plane belonged to the halfling pantheon who mostly shared the plane rather than carve out personal realms. The plane of Green Fields was a rural paradise of small, non-permanent settlements where the inhabitants alternated hard work with enjoying the fruits of their labor. Somewhere on this plane was a portal to Tymora's realm in Brightwater.


 * House of Knowledge
 * Oghma, Gond, Milil, and Deneir shared this plane, with its ancient oak forests and spring-fed pools occasionally interrupted by buildings which formed the Library of All Knowledge. In these buildings were the records of every field of academic study: spells and magic items, songs and music, science and alchemy, history and prophecy, writing and language. The only known portal to and from this plane was held by Gond and it connected his workshop to Flandal Steelskin's realm in the Golden Hills.


 * House of the Triad
 * This plane was composed mainly of three large mountains surrounding a central gigantic mountain called Celestia. Mount Celestia had seven layers, each connected by portal from the highest point of one layer to the lowest point of the next higher layer. Only the lowest layer of Celestia was accessible from elsewhere on this plane or the Astral Plane. The gods Ilmater, Torm, and Tyr each had a realm atop one of the lesser mountains while Helm and Siamorphe maintained realms around the bases of the four peaks. No portals to or from the House of the Triad were known to exist but all color pools and temporary gates were guarded by Helm's watchtower and a powerful guardian. Bahamut had a palace made of gems and precious metals that wandered about the lower layers of Celestia. After the Spellplague, Celestia and its surrounding peaks were set adrift in the Astral Sea.

Fiendish Planes
Deities and entities of the Evil persuasion inhabited the set of planes known as the Fiendish Planes. Separate branches of the Astral Plane connected each of them to the Prime Material Plane and most of them were also coterminous with one or two neighbors via the River of Blood, the only exceptions were the Demonweb Pits and the Supreme Throne. The River of Blood was thought to originate in the Abyss and flow in order through Blood Rift, the Nine Hells, the Barrens of Doom and Despair, Clangor, Fury's Heart, Hammergrim, Nishrek, and the Deep Caverns before cascading into the Fated Depths.


 * The Abyss
 * More layers than all the other planes combined, the Abyss was practically a universe of chaos and evil unto itself, overflowing with endless hordes of demons ruled by tyrannical demon lords. Every type of landscape and climate imaginable could be found here, as long as it was tainted, touched, or tortured by evil. Visitors arriving via the Astral Plane could enter any layer and portals did exist between the various layers but they were neither constant nor consistent. The shifting nature of this plane brought new layers in conjunction with the River of Blood, so travel by boat was also different each time. Known portals existed between the Abyss and the Barrens of Doom and Despair, Clangor, the Demonweb Pits, the Fugue Plane, and Hammergrim. Intermittent connections also existed to the Fated Depths and Deep Caverns.


 * Barrens of Doom and Despair
 * Just as the name implies, this plane was nothing but deserts of various sorts, from sandy wastes to rocky badlands to diseased swamps to icy tundras&mdash;vast expanses of terrain inimical to life, under a sunless red sky hidden behind black clouds. The only landmarks to break the monotony were the River of Blood and the rare tower or citadel marking the realm of Bane, Beshaba, Hoar, Loviatar, or Talona. Portals existed to Hammergrim and the Abyss and occasionally the Blood Rift would connect to this plane allowing the combatants of the Blood War to escape or pursue each other across the border.


 * Blood Rift
 * This unusual plane was the main battleground in the Blood War because it was coterminous with both the Nine Hells and the Abyss along the River of Blood. The terrain was similar to parts of the Barrens of Doom and Despair which some cosmologists believed was because the Blood Rift had broken off from there and became a floating plane, anchored between the homes of the demons and the devils but able to occasionally make contact with other Fiendish planes. In addition to the Barrens, the Blood Rift was known to have connected to Clangor, Deep Caverns, Demonweb Pits, Fated Depths, Fury's Heart, Hammergrim, Nishrek, and the Supreme Throne at some point in history. No deities where known to make their home here but all manner of yugoloths lived here and played roles on both sides of the Blood War, perhaps for their own mysterious agenda.


 * Clangor
 * Clangor was a plane that facilitated a never-ending cycle of war by rapid healing, regeneration, and full resurrection for all combatants every sunrise. The terrain was made of solid iron, rusting iron, and rust dust which was constantly kicked up by battle and colored the sky blood-red. The sound of marching feet and the clash of weapons echoed loudly throughout the plane, the sound carried to even the far corners by the solid iron ground. In addition to the River of Blood, portals to the Abyss and the Nine Hells existed but they belonged to the goblinoid deities Maglubiyet and Hruggek and the kobold deity Kurtulmak. The only "cities" were warrens of caves carved in the iron crust, itinerant villages based around a single temporary structure, or the rare armed fort.


 * Deep Caverns
 * This plane was similar to the Elemental Plane of Earth in that it was solid stone with no light or sky. An endless maze of tunnels, caves, fissures, and chasms riddled the rock like worm-eaten wood, accommodating the creatures attracted to the plane and the petitioners of the beholder, mind flayer, and troglodyte races. Each of the primary deities, the Great Mother of the beholders, Ilsensine of the illithids, and Laogzed of the troglodytes, controlled a region of the plane widely separated from the others and could command the stone under their control to open, close, or take shape at their will. Portals existed between this plane and many others, but most lead to the Abyss.


 * Demonweb Pits
 * The sundering of the Demonweb Pits from the Abyss corresponded closely with the advent of the World Tree cosmology model which was formulated to explain the new order of the multiverse. Instead of spider's webs, Lolth's new plane was woven of matter itself with great strands spanning the void, forming bottomless pits between them and disallowing the River of Blood to pass through. Most of the drow pantheon (Ghaunadaur, Kiaransalee, Selvetarm, and Vhaeraun) had realms here that were like beads on the strands of the Demonweb, but Lolth kept herself aloof. Portals back to the Abyss were known to exist, some fixed, some random.


 * Fated Depths
 * This plane was similar to the Elemental Plane of Water except that the endless depths were completely dark and filled with brackish unholy water exclusively. The River of Blood ended its long journey from the Abyss here, dumping the pollution and effluvium collected along the way and fostering a feeding frenzy among the foul fish and fiends who lived here. Blibdoolpoolp of the kuo-toa and Sekolah of the sahuagin made this plane their home. The Elemental Plane of Water and layers of the Abyss that were water-dominant or that had wide or deep bodies of water were connected by portal to this plane. A portal to Umberlee's home in Fury's Heart was also known to cosmologists.


 * Fury's Heart
 * Violent weather wracked this plane almost constantly, the only respite was beneath the surface of Umberlee's Blood Sea or occasionally in Malar's Land of the Hunt. Talos and Auril also had realms here, equally inhospitable in their own way. The terrain was much like that found in the Barrens of Doom and Despair but many creatures managed to eke out an existence and petitioners often took the form of primeval animals upon arrival. Umberlee kept a portal to the Fated Depths and the River of Blood flowed through Malar's demesne and had a tributary to the Blood Sea.


 * Hammergrim
 * Known for its master weapons- and armor-craftsmen as well as its joyless, depressing attitude and atmosphere, the gargantuan fortress of Hammergrim was the afterlife for the vast majority of the duergar. The plane itself was a windowless citadel with outer walls so thick it would take a normal human fifteen minutes to run from outside to inside. Deities Deep Duerra and Laduguer each had a realm in Hammergrim while the evil gnome deity Urdlen tunneled in the ore-rich crust below. There was a connection between Urdlen's realm and the Abyss, and portals to the Barrens of Doom and Despair frequently opened, much to the dismay of the duergar petitioners. The River of Blood flowed lazily across this plane as well.


 * Nine Hells
 * The home of the devils was a layered plane, only the first of which (Avernus) was accessible via the Astral Plane. Each layer except the bottom was punctured by a huge hole perhaps tens or hundreds of miles/kilometers across that dropped a few miles/kilometers to the next lower layer. The holes were roughly concentric and progressively smaller, forming a nine-tiered pit of gigantic proportions. Avernus was also coterminous with the Blood Rift and portals were known to exist leading to the Barrens of Doom and Despair and Clangor. The River of Blood not only flowed through Avernus but had tributaries and cascades on every layer. No deities made their home here, but each layer was ruled by a powerful archdevil, each of whom answered to Asmodeus, the ruler of the ninth and lowest layer.


 * Nishrek
 * Similar to Clangor, this plane also had a minor positive-dominant trait that constantly healed the wounded and resurrected the dead every sunset. Home of the orc pantheon led by Gruumsh, orc petitioners from every tribe continually demonstrated their prowess in nightly battle, hoping to win his favor. Nishrek had very little flora or fauna and was an infinite plain with numerous battlements, trenches, and fortifications created or destroyed over the years. No permanent portals were known to exist, but the River of Blood flowed through Nishrek and the roving Blood Rift frequently became coterminous, causing havoc with battle plans on all sides of both conflicts.


 * Supreme Throne
 * Once just a realm in the Great Wheel plane of Limbo, the Supreme Throne became its own plane in the World Tree model, although completely isolated except via the Astral Plane. The Mad God Cyric eventually chose this place as a home base, placing his decrepit and decaying castle on an otherwise featureless, desolate plane that was constantly swept by howling winds. All laws and features of the Supreme Throne bent to the mercurial whim of Cyric.

Neutral Planes
There was also a group of planes whose inhabitants did not adhere strictly to either good or evil, or tolerated the presence of opposing alignments. The Neutral Planes, sometimes called the Unaligned Planes, were connected to the Astral Plane in the usual fashion but were host to neither a branch of the World Tree nor a channel of the River of Blood.


 * Dragon Eyrie
 * This plane consisted of one colossal mountain, from dark roots to a snowy peak, on, under, and about which the draconic pantheon maintained realms of appropriate habitat for their petitioners. No settlements except an occasional hermit were known to exist on this plane, as dragonkind guarded their solitude fiercely. A portal to Arvandor was maintained by Hlal but there may have been temporary connections as each deity wished. Tiamat lurked in a dark cave deep below the mountain and had a portal to another realm in Heliopolis.


 * Heliopolis
 * Heliopolis was a vast sandy desert baked by an intense sun and cut by a great river of holy water called the River Isis. All lands along the river were lush and fertile and provided habitat for Mulhorandi petitioners. The entire plane was home to most of the Mulhorandi pantheon who gravitated around huge pyramids, temples, and stone monuments built in their honor along the riverbank and out into the desert. No portals were known to connect to Heliopolis except for Tiamat's closely guarded gate, likely somewhere in the evil Set's dark domain.


 * House of Nature
 * This plane was an unspoiled natural wilderness encompassing the climates and habitats of most natural creatures without any buildings or trappings of civilization. Many nature-oriented deities resided here, including Chauntea, Eldath, Gwaeron Windstrom, Lathander, Lurue, Mielikki, Nobanion, Shiallia, and Ubtao as well as a great number of guardinal paragons and the deities of sentient creatures such as centaurs, all coexisted in relative harmony according to the laws of nature. A shared portal to Arvandor was maintained by the deities who had interests there. It was known that Nobanion kept a permanent portal to Gulthmere Forest.


 * Jotunheim
 * Another vast plane of wilderness but on a scale to match the deities in the Giant pantheon, Jotunheim was a land of extremes. Everything was bigger, grander, or harsher than normally found on the Prime Material Plane: trees, plants, animals both natural and magical, buildings, caverns, rivers, mountains, volcanoes, and even climates. This plane was host to both a fire-dominant and a cold-dominant region (the realms of Surtr and Thrym respectively). The only known portal to this plane connected Surtr's domain to the Elemental Plane of Fire.


 * Warrior's Rest
 * The ironically named Warrior's Rest was another plane where battles constantly raged, similar to Clangor and Nishrek. However, chaos reigned here and the landscape, which was mainly rocky desert, mesas, buttes, and badlands, slowly morphed in a fashion similar to the Great Wheel cosmology plane of Limbo except not as severely or rapidly. Beings with sufficient wisdom could alter the terrain in their immediate vicinity by exerting their will. There was also a large body of seawater for naval battles. No portals were known to exist on this plane. Tempus was the overlord here, but he allowed other deities of war and strife some autonomy in their realms.

Cynosure and the Fugue Plane
In the World Tree cosmology model there were two planes that, from a mortal's point of view, existed outside the model, disconnected from the Astral tree structure, but still played very important roles in the afterlife and the struggles between the Powers.
 * Cynosure
 * A small, finite demiplane, Cynosure was a neutral meeting place for all the deities and elemental lords of divine rank 0 or higher. The entire plane consisted of a large open-air amphitheater or meeting hall adorned with pillars under a starry night sky. Just outside, the structure was ringed with portals, one to each divine realm, that could only be activated by deities. No magic worked other than the portals and no color pools existed on Cynosure, preventing all Astral travel.


 * Fugue Plane
 * The Fugue Plane consisted of a flat, featureless plain surrounding the City of Judgment. According to this cosmology model, all souls eventually traveled to this plane to await judgment or to be taken to the realm of their patron deity. No color pools appeared on this plane. The only portals were the ones sanctioned by Kelemvor to the Nine Hells and the occasional unsanctioned portal used in a raid on the city by the demons of the Abyss. The only sure way for mortals to get here was to die.

Inner Planes
The Elemental and Energy planes contained the building blocks of the multiverse. Each plane was beautiful and deadly in its own way and was inhabited by strange and unique creatures. The mode of travel to the Inner Planes changed from ethereal in the Great Wheel cosmology to astral: travelers no longer had the capability of moving through the Border Ethereal before selecting an entry point. Instead they viewed their destination through a color pool in the Astral before passing through it to arrive on the new plane. The four Elemental Planes and two Energy Planes were no longer directly connected nor did they form para- and quasi-elemental planes as they did in the older model. The concept of the Elemental and Energy Planes being at the "root" of the tree-like Astral Plane was common, but since all paths lead through the nexus of the Prime Material Plane it was really just a matter of perception.

Along with the advent of the World Tree cosmology model was the introduction of planar traits to describe all the types and characteristics of planes and layers. The Inner Planes themselves were mostly unchanged from the Great Wheel cosmology model, the major difference being that time no longer moved twice as fast on the Inner Planes than on the Prime Material Plane. In the terminology of planar traits, the Great Wheel model used the Flowing Time trait with 1 true day equaling 2 subjective days, and the World Tree model used the Normal Time trait.

Elemental Planes
In this cosmology model, before the Spellplague, the Elemental Planes were individual infinite planes of almost pure elemental substance. The most powerful beings on these planes were called Elemental Lords and were worshiped as deities in a few places on Toril. After the Spellplague they were revealed to be primordials.
 * Elemental Plane of Air
 * An endless blue sky with occasional intrusions of the other elements, the Plane of Air was the most hospitable of the Elemental Planes, but could still be very dangerous to the uninitiated. Travelers had to either be able to fly or master the technique of picking a direction for "down" and then falling in that direction until they hit something or picked a new direction. Landing safely on the surface of a floating island was a very tricky maneuver. Akadi the Lady of the Winds was the supreme power on this plane.


 * Elemental Plane of Earth
 * This plane was the most hazardous and inhospitable of the four Elemental Planes because it was nearly solid matter with few pockets of breathable air or water. The only well-maintained caverns were those found in the Great Dismal Delve, a slave-labor mining operation run by the dao. Rich veins of metals, and gems lured many prospectors but the environment and inhabitants, (which often looked just like the environment), were extremely dangerous. Grumbar the King of the Land Below the Roots was the ruler of this plane.


 * Elemental Plane of Fire
 * Air, water, and earth are practically indistinguishable between the Prime Material Plane and their Elemental Planes, but not so with fire. Elemental Fire produces light, heat, and smoke like regular fire but does so without fuel or air and can take a solid, liquid, or gaseous form. Travelers to this plane required immunity to or protection from fire, and a way to breathe. Few places were hospitable to visitors but the most famous was the City of Brass ruled by the efreets. Kossuth Lord of Flames was the ultimate power on this plane.


 * Elemental Plane of Water
 * No crushing pressure, but little breathable air, the Plane of Water was like an infinite swimming pool with no bottom or surface. Visitors needed the same abilities and precautions as they would being submerged in any large body of water. Tides, currents and whirlpools could pose significant threats to the unprepared. Aquatic life of myriad varieties lived (and hunted) here. Istishia the Water Lord held sway over this liquid domain.

Energy Planes
The Positive and Negative Energy planes were the source and drain, the push and pull, of life and death. Extremely inimical to mortal life, only the minor-dominant areas could be inhabited and they were in constant danger of being overwhelmed by a major-dominant flux. The Negative Plane drained all energy while the Positive Plane was pure energy in such abundance that mortal forms could not contain it. During the Spellplague all the Elemental and Energy Planes merged into the Elemental Chaos, but the goddess Shar folded part of the Negative Energy plane into the Plane of Shadow, forming the Shadowfell.
 * Negative Energy Plane
 * An eternally dark, barren place with no landmarks that ate light, heat and life. Some minor-dominant areas were favorites of necromancers because they could survive and their magic was enhanced.


 * Positive Energy Plane
 * Continual bursting energy so intense it overwhelmed mortal senses, filling any vessel with life energy until it overflowed and exploded, disintegrating into component elements which then joined the frenetic vibration. Minor-dominant areas were prized for the enhanced healing properties.