The Planes

In the myth of the Progenitor Wyrms—a tale told in some form by nearly every culture—the three Progenitors work together to forge all of creation. After time unknown, their creation consisted of thirteen planes, each one an idealized exploration of a particular concept: Life and death, war and peace, heat and cold, order and chaos, the natural, the alien, the bright, the shadow and the dream.
All of these planes overlap with Eberron in some way, and they influence and are influenced by the Material Plane. The intensity of this influence waxes and wanes; scholars often depict the planes as orbiting Eberron-sometimes coming close, other times far away-though this manner of expression is merely a metaphor for their shifting influence. When another plane's influence on the Material Plane is especially strong, the plane is said to be coterminous. When its influence is weak, a plane is remote. The state of a plane can be important for performing epic rituals, creating of eldritch machines, or interacting with extraplanar entities.

Manifest Zones

At certain places in the Material Plane, the barriers between worlds are thin, and some characteristics of another plane can bleed through into the material world. These places are called manifest zones, and the nature of each one is strongly shaped by the plane it connects to. The city of Sham is located in a manifest zone linked to Syrania that keeps its towers reaching toward the sky and aids flight. Ghosts might linger in a manifest zone associated with Dolurrh, while a manifest zone tied to Lamannia might have wild vegetation and enhance druidic magic.
A manifest zone might include a portal that allows free passage from either plane to the other. Most manifest zones have reliable, persistent effects. Some have only weak connections to their planes, and their properties influence the world only when the plane is coterminous.

The Planes

Name	Essence	Inhabitants	Examples of Influence
Daanvi, the Perfect Order	Discipline and law	Modrons, archons and devils	Prevention of lies, spontaneous organization, compulsion to obey orders
Dal Quor, the Region of Dreams	Dream and memory	The Quori	None; plane has been severed from the Material
Dolurrh, the Realm of the Dead	Despair and transition	Souls of the dead, psychopomps and shadar-kai	Apathy, despair, enhanced necromancy and restless dead crossing back over
Fernia, the Sea of Fire	Flame, change and destruction	Fiends, chaotic celestials, elementals and creatures of fire	Increased temperatures, enhanced fire magic, improved creation of items
Irian, the Eternal Dawn	Light, hope and positive energy	Angels, archons and celestials	Healing of wounds, enhanced radiant magic, slowed ageing and curing of disease
Kythri, the Churning Chaos	Chaos, change and power	Unstable elementals, slaadi and githzerai	Ability to morph terrain by thought, unpredictable casting of spells, strange warping of nature
Lamannia, the Twilight Forest	Nature and the elements	Beasts, plants and all elementals	Spontaneous creation of elementals, overgrowth of plants, animals running wild
Mabar, the Endless Night	Darkness, entropy and negative energy	Undead, fiends and shadows	Light is snuffed out, evil undead rise, disease and blight take hold
Risia, the Plain of Ice	Cold, preserved, unchanging	Fiends, elementals and creatures of ice	Temperatures plummet, fires are extinguished, food doesn't rot
Shavarath, the Battleground	War, conflict and blood	Angels, demons and devils in eternal battle	Combat becomes more lethal, tensions built towards hostility, weapons are easier to forge
Syrania, the Azure Sky	Peace, sky and virtue	Angels, followers of the Sovereigns	Flight and levitation is easy, skies become clear, aggressive thought becomes difficult
Thelanis, the Faerie Court	Individuality, desire, will and nature	The fey, plants, beasts, chaotic celesitals	Illusions are enhanced, time and space become distorted, animals and plants fall under fey influence
Xoriat, the Realm of Madness	Insanity, mutation, the alien	Aberrations, the daelkyr	Magic becomes unpredictable, creatures begin to mutate, delusions and paranoia become common