Planes of Existence

The cosmos teems with a multitude of worlds as well as myriad alternate dimensions of reality, called the  planes of magic.

Many spells and magic items can draw energy from these planes, summon the creatures that dwell there, communicate with their denizens, and allow adventurers to travel there.

The Material Plane
The Material Plane is the nexus where the philosophical and elemental forces that define the other planes collide in the jumbled existence of mortal life and mundane matter.

Beyond the Material
Beyond the Material Plane, the various planes of existence are realms of myth and mystery. They're not simply other worlds, but different qualities of being, formed and governed by spiritual and elemental principles abstracted from the ordinary world.

Transitive Planes
The Ethereal Plane and the Astral Plane are called the Transitive Planes. They are mostly featureless realms that serve primarily as ways to travel from one plane to another. Spells such as etherealness and astral projection allow characters to enter these planes and traverse them to reach the planes beyond.

The  Ethereal Plane  is a misty, fog-bound dimension that is sometimes described as a great ocean. Its shores, called the Border Ethereal, overlap the Material Plane and the Inner Planes, so that every location on those planes has a corresponding location on the Ethereal Plane. Certain creatures can see into the Border Ethereal, and the see invisibility and true seeing spell grant that ability. Some magical effects also extend from the Material Plane into the Border Ethereal, particularly effects that use force energy such as forcecage and wall of force. The depths of the plane, the Deep Ethereal, are a region of swirling mists and colorful fogs.

The  Astral Plane  is the realm of thought and dream, where visitors travel as disembodied souls to reach the planes of the divine and demonic. It is a great, silvery sea, the same above and below, with swirling wisps of white and gray streaking among motes of light resembling distant stars. Erratic whirlpools of color flicker in midair like spinning coins. Occasional bits of solid matter can be found here, but most of the Astral Plane is an endless, open domain.

Inner Planes
The Inner Planes surround and enfold the Material Plane and its echoes, providing the raw elemental substance from which all the worlds were made. The four  Elemental Planes --Air, Earth, Fire, and Water--form a ring around the Material Plane, suspended within the churning  Elemental Chaos.

At their innermost edges, where they are closest to the Material Plane (in a conceptual if not a literal geographical sense), the four Elemental Planes resemble a world in the Material Plane. The four elements mingle together as they do in the Material Plane, forming land, sea, and sky. Farther from the Material Plane, though, the Elemental Planes are both alien and hostile. Here, the elements exist in their purest form--great expanses of solid earth, blazing fire, crystal-clear water, and unsullied air. These regions are little-known, so when discussing the Plane of Fire, for example, a speaker usually means just the border region. At the farthest extents of the Inner Planes, the pure elements dissolve and bleed together into an unending tumult of clashing energies and colliding substance, the Elemental Chaos.

Outer Planes
If the Inner Planes are the raw matter and energy that makes up the multiverse, the Outer Planes are the direction, thought and purpose for such construction. Accordingly, many sages refer to the Outer Planes as divine planes, spiritual planes, or godly planes, for the Outer Planes are best known as the homes of deities.

Upper and Lower Planes
The planes with some element of good in their nature are called the  Upper Planes. Celestial creatures such as angels and pegasi dwell in the Upper Planes. Planes with some element of evil are the  Lower Planes. Fiends such as demons and devils dwell in the Lower Planes. A plane's alignment is its essence, and a character whose alignment doesn't match the plane's experiences a profound sense of dissonance there. When a good creature visits Elysium, for example (a neutral good Upper Plane), it feels in tune with the plane, but an evil creature feels out of tune and more than a little uncomfortable.