D&D 2024 Cosmology Guide

Introduction

Chapter 6 of the 2024 Dungeon Master's Guide lays out the default D&D multiverse: how planes relate to each other, how characters travel between them, and what the named planes are like. This guide follows that structure, beginning with planar structure and travel before touring the planes a DM is likely to use.

For the DM-facing rules this chapter assumes (environmental effects, curses, hazards), see the DM's Toolbox guide. Return to the Dungeon Master Guides hub for the full chapter map.

The Shape of the Multiverse

Since travel between planes runs almost entirely through magical portals, no one in the multiverse has ever actually mapped it from above - the "shape" of the cosmology is a theoretical model, not a verified geography. The DMG's default model, the Great Wheel, sorts every plane into four categories:

The Positive and Negative Planes sit outside this whole structure, enfolding it and supplying the raw forces of life and death that underlie everything else in the multiverse.

The book is explicit that this is only one option. If the Great Wheel doesn't fit your campaign, alternatives it names outright include planes arranged among the roots and branches of a cosmic tree, a simplified cosmology with a single undifferentiated Elemental Plane and an Overheaven/Underworld pair instead of the full Outer Plane roster, or planes arranged in a system of orbits where influence on the Material Plane grows the closer a plane draws to it. Swapping models doesn't change how any individual plane functions - only how you describe its position relative to the others.

Inner Planes

The four Elemental Planes - Air, Earth, Fire, and Water - form a ring immediately around the Material Plane, with the Para-elemental Planes (Ice, Magma, Ooze, Ash) occupying the borders between adjacent pairs. At their innermost edges, closest to the Material Plane, the elements mingle much as they do at home, forming recognizable land, sea, and sky - just dominated by one element. Push farther out and the planes grow more extreme and hostile: solid earth, unbroken flame, crystal-clear water, or unsullied air in their purest form, populated by creatures made of pure element and the Elemental Princes of Evil. At the outermost extent, the pure elements dissolve entirely into the Elemental Chaos, an unending tumult where the four elements clash and bleed together.

Notable Inner Plane locations: the City of Jewels, capital of the dao on the Plane of Earth, built almost entirely from precious stones and metals its inhabitants mine obsessively; the City of Brass, the efreet's ornate capital on the Plane of Fire and the single most likely place to buy a rare magic item in the multiverse; and the Citadel of Ten Thousand Pearls, seat of the marid emperor on the Plane of Water.

Outer Planes

The Outer Planes are realms of spirituality and thought rather than simple geography - a plane like Elysium isn't just where good creatures live, it's the embodiment of goodness itself, a place evil literally cannot abide. Planes with an element of good are the Upper Planes; those with an element of evil are the Lower Planes. A creature whose alignment clashes with a plane's alignment feels a persistent, wearing dissonance there.

Distance on the Outer Planes is close to meaningless - a tour of all nine layers of the Nine Hells could take a single day or several weeks, entirely at the whim of the powers who rule there. Most multi-layered Outer Planes are visualized as a stack of related realms, called layers, with most portals from elsewhere arriving on the first layer.

Planar Dissonance. A Celestial who lingers on a Lower Plane, or a Fiend who lingers on an Upper Plane, for more than a few hours suffers for it: after a Long Rest on hostile ground, it makes a DC 10 Constitution save. On a failure, it subtracts 1d4 from every D20 Test until it finishes a Long Rest somewhere its nature isn't opposed - and the penalty stacks with each subsequent failed save.

The Outer Planes by Alignment

Getting There: Planar Portals and Travel

Planar portals are stationary connections between a specific spot on one plane and a specific spot on another - some look like doorways or fog-shrouded passages, others are entire locations (standing stones, towers, ships, even towns) that exist on multiple planes at once. Vortices join an Elemental Plane to a matching Material Plane location, like a volcano's magma pool leading to the Plane of Fire.

Finding a portal is often the adventure. Most are guarded by a powerful magical creature tied to the destination plane (a djinni, a sphinx, a titan), and most open only under a specific requirement:

Spells. Plane Shift and Gate transport creatures directly to another plane, with different degrees of precision. Etherealness opens the Ethereal Plane. Astral Projection sends a creature's astral self into the Astral Plane, from which the Outer Planes are reachable.

The Ethereal Plane

The Ethereal Plane is a fogbound dimension whose "shores," the Border Ethereal, overlap the Material Plane, the Feywild, the Shadowfell, and the Inner Planes - every location on those planes has a matching spot in the Border Ethereal, usually visible out to 60 feet but grayish and indistinct. Creatures in the Border Ethereal can't normally be attacked by (or attack) creatures on the overlapped plane, and gravity doesn't apply. Push deeper into the Deep Ethereal - typically reachable only via Plane Shift, Gate, or a portal - and visibility drops to 30 feet of swirling mist, broken by curtains of vaporous color that each lead to a different plane's Border Ethereal. A trip through the Deep Ethereal from one curtain to another takes 1d10 x 10 hours regardless of origin or destination.

Watch for ether cyclones - sudden, destructive storms that give a 1-minute warning (a deep thrum) to anyone with Passive Perception 15+. The Ethereal Plane is also home to the Radiant Citadel, a floating refuge built from a single massive fossil by twenty-seven Material Plane civilizations, and a natural home base for a campaign built around exploring new worlds.

The Astral Plane

The Astral Plane is where disembodied souls travel to reach the Outer Planes - a great silvery sea, empty but for drifting stone chunks (the petrified remains of dead gods) and color pools, shimmering portals to specific planes identified by a fixed color (amethyst leads to the Abyss, gold to Mount Celestia, cold blue to the Nine Hells, and so on down the full Astral Color Pools table). Movement on the Astral Plane happens by simply thinking about a destination; travel time is up to the DM, with a specific location taking roughly 4d6 days and a general one (like "the nearest color pool to the Abyss") taking 1d4 x 10 hours. Creatures native to the Astral Plane, such as githyanki, don't age or need food or water there - which is exactly why they keep outposts on other planes for their children to grow up in.

Bobbing in the Astral Plane are Wildspace systems, airless expanses where the Astral Plane overlaps the Material Plane and its stars and worlds become directly accessible - every Material Plane world sits inside one. Watch for psychic winds, storms of stray thought that can divert, delay, or disorient a party crossing the Deep Astral (roll on the Psychic Wind Location Effects and Psychic Wind Psychic Effects tables for the specifics).

Planar Adventuring

The DMG treats the planes as a mid-to-high-level destination: its own Planar Adventure Situations table is written for characters of level 11 and up, mixing recovering a lost soul from the Outer Planes, chasing a prophecy only a long-dead oracle can avert, or investigating a god who's stopped answering Commune spells.

The Blood War is the backdrop for most Lower Planes content: an ages-long, unending conflict between the demon hordes of the Abyss and the devil legions of the Nine Hells, fought mainly across those two planes but spilling anywhere Fiends of both stripes cross paths - including the Material Plane. Powerful Fiends chase any advantage in the war and sometimes drag mortal adventurers into their schemes; Celestials mostly let evil consume itself, but intervene when the fighting threatens to spill somewhere it shouldn't.

Alignment drift. At your discretion, a creature that lingers on an Outer Plane that isn't home starts absorbing its ethos - kindness on the Upper Planes, cruelty on the Lower Planes, independence on Limbo, loyalty on Mechanus. Treat this as a roleplaying prompt for the player, not an automatic mechanical shift, and consider Heroic Inspiration as a reward for playing it out.

Tour of the Multiverse

The following sections focus on planes that commonly support a planar campaign.

Abyss

The Abyss is chaos and evil made physical - a virtually endless spiral of layers, each more appalling than the last, numbered by the order Sigil's explorers cataloged them rather than by any logical sequence. Layer 1, the Plain of Infinite Portals, is the best way in or out, riddled with portals to other layers and to Pandemonium, Sigil, and the Astral Plane. Deeper layers belong to specific demon lords: Azzagrat (layers 45-47) to Graz'zt, a realm of decadent cruelty behind a veneer of courtly civility; the Demonweb (layer 66) to Lolth, the Spider Queen; the Gaping Maw (layer 88) to the two-headed Demogorgon; Thanatos (layer 113) to Orcus, Demon Prince of Undeath; the Slime Pits/Shedaklah (layer 222) to Juiblex and Zuggtmoy; the Death Dells (layer 422) to Yeenoghu, patron of gnolls; and the Endless Maze (layer 600) to Baphomet. The Abyss actively corrupts other planes it touches - a portal opened to it anywhere else can seed pockets of Abyssal evil that eventually get pulled back into the Abyss itself.

Nine Hells

The ultimate plane of law and evil, ruled from the bottom up by Asmodeus, archduke of the ninth layer, Nessus, and unbeaten at the top of a strict devil hierarchy. To reach Nessus a traveler must descend all eight layers above it in order - fastest via the River Styx, which plunges from layer to layer. Each layer has its own archdevil and character: Avernus (Zariel, battlefield wasteland, arrival point for most visitors, also Tiamat's prison), Dis (Dispater, an iron canyon-city), Minauros (Mammon, a stench-ridden bog city), Phlegethos (Belial and Fierna, a volcanic obsidian fortress-city), Stygia (Levistus, frozen and lightning-wracked), Malbolge (Glasya, an endless crumbling slope), Maladomini (Baalzebul, ruin-choked wasteland), Cania (Mephistopheles, ice-locked cities), and Nessus itself (Asmodeus's citadel of Malsheem). Devils here obey their superiors' laws to the letter while constantly scheming against each other - Asmodeus survives by playing every rival off the others.

Mechanus, Limbo, and the Neutral Planes

Mechanus and Limbo sit at opposite philosophical poles: Mechanus is a plane of perfect, clockwork law where modron Constructs enforce absolute order, while Limbo is raw, will-shaped chaos where slaadi Aberrations thrive on nothing staying fixed for long. The Outlands sits at the literal and philosophical center of the Great Wheel, linking every Outer Plane - at its center rises the Spire, above which floats Sigil, the City of Doors, a ring-shaped city built on the inside of its own ring, technically a plane in its own right rather than part of the Outlands. Sigil is a trading hub for goods and planar information alike, ruled by the enigmatic Lady of Pain, whose true nature no one in the setting claims to know.

Feywild

The Feywild, the Plane of Faerie, occupies the same cosmological space as the Material Plane but as a more marvelous, more emotionally reactive mirror of it - flowers wilt near an argument, grass withers under malice, birds sing near joy. Time and geography here are mutable; roads shift, and distance doesn't behave predictably. Much of the plane is carved into Domains of Delight, territories ruled by individual archfey and shaped by their moods: the Summer Court (Queen Titania, perpetual pastoral summer and rigid courtly etiquette), the Gloaming Court (the Queen of Air and Darkness, perpetual twilight and instinct over ritual), Prismeer (the archfey Zybilna, a wish-granting realm split into swamp, forest, and mountain thirds), and Fablerise (the spider archfey Yarnspinner, a domain of woven root-tunnels).

Fey crossings connect specific, often beautiful Material Plane locations to a near-perfect Feywild mirror - stepping into a clearing, a pool, or a mushroom ring can be all it takes, though most crossings only open under specific, often obscure conditions.

Time distortion is the Feywild's signature hazard: after a creature or group spends at least a day there, the optional Feywild True Time Warp table can convert that time into anywhere from minutes to years back on the Material Plane - a party can walk out after what felt like a single day to find a decade has passed at home. A creature also risks losing its memories of the visit entirely on a failed DC 10 Wisdom save (Fey creatures and anyone with Fey Ancestry auto-succeed).

Shadowfell

The Shadowfell, the Plane of Shadow, is the Feywild's grim twin - a black, starless sky over a Material Plane mirror gone bleak and sinister: a mountain might become a skull-shaped outcropping, a forest's branches reach to snare passing travelers. Shadow crossings form in places touched by death (battlefields, graveyards, tombs) and only manifest in darkness, closing at the first light. Tucked in a remote corner of the plane are the Domains of Dread, mist-shrouded demiplanes where the Dark Powers imprison history's most wicked beings as Darklords - given real power, but trapped in realms twisted to mock their own desires. Extended time in the Shadowfell risks Shadowfell despair: a failed DC 10 Wisdom save (checked no more than once a day) inflicts a random despair effect from apathy to dread to delusion, curable with Calm Emotions, a curse-removing effect, or by shaking it off with a DC 15 Wisdom save after a Long Rest.

Elysium, Arcadia, Arborea, and Bytopia

The good-aligned Upper Planes each embody a different flavor of goodness. Elysium is unfettered kindness and tranquility, threaded by the River Oceanus and easy to never want to leave. Arcadia is order in service of the common good - perfectly straight roads, orchards in ruler-straight rows, weather governed by four allied demigod Storm Kings. Arborea is passionate extremity - towering mountains, sudden storms, and inhabitants whose devotion to good comes wrapped in equally intense emotion. Bytopia and Ysgard round out the neighborhood: Ysgard is the eternal battlefield of slain heroes, where any creature killed there (short of a Construct or Undead) rises whole again at the next dawn to fight another day.

Gehenna, Hades, and Pandemonium

The Lower Planes outside the Abyss and Nine Hells each carry their own flavor of misery. Gehenna is volcanic and treacherous, birthplace of the greedy, selfish yugoloths, where nothing is trustworthy and every bargain hides a trap. Hades and Pandemonium lean into despair and madness respectively - Hades a gray, memory-eroding wasteland, Pandemonium a plane of howling winds that drive visitors slowly insane.

Far Realm

Outside the multiverse entirely, the Far Realm may be a wholly separate universe with its own physical and magical laws. Where its stray energy leaks into another plane, matter warps into alien shapes that defy ordinary geometry - aberrations like mind flayers and beholders either originate there or were reshaped by its influence. It has no known reliable portals; the one famous exception, opened by ancient elves inside a mountain called Firestorm Peak, ended in a civilization's collapse and is now lost.

Related Guides

For the DM-only rules this chapter assumes (curses, environmental effects, hazards), see the DM's Toolbox guide. For fitting a planar arc into a longer story, see the Creating Campaigns guide and the Creating Adventures guide. Return to the Dungeon Master Guides hub for the full chapter map, or see the Best D&D 2024 Magic Items guide for items your planar-traveling party might bring home.