The Astral Sea, also known as Siberys, is the plane of the gods and demigods, an ideal for most concepts; chaos, order, light, dark, etc. It includes Daanvi, Irian, Lamannia, Mabar, Shavarath, and Syrania.

• Daanvi
  • Daanvi, the Perfect Order, is the manifestation of law in the Planes of Eberron, and its opposite is Kythri. All things of Daanvi live in perfect harmony born of order. On the plane all spells with the lawful descriptor are automatically maximized and enlarged, while chaotic spells are impeded. Though there are no founded links between changes in Eberron during coterminous and remote periods of Daanvi, many claim that centuries in which Daanvi are coterminous are historically more stable while periods when it is remote are historically unstable.

• Irian
  • Irian, the Eternal Day, is a plane of positive energy. Some might equate this to paradise. A brilliant white sun hangs in a beautiful blue sky while rivers of liquid glass flow down from mountains of quartz. The plane is suffused with positive energy, not enough to harm life, but enough to sustain unusual forms of life, though not necessarily good aligned creatures. Just like its opposite, Mabar, the energies of this plane work in opposition to the natural decay and birth of life. In the short period of time when Irian is coterminous with the Material Plane life blossoms. Days are brighter, colors are vibrant and sensations are more intense. Positive energy spells are enhanced in these times, however the manifestations occur only for the hour surrounding noon. The plane is coterminous for ten days in the month of Eyre. When Irian is remote the opposite takes effect. Night becomes darker, numbness hangs in the air and spells with positive energy are less powerful. These manifestations occur during the autumn month of Sypheros for ten days. An almost permanent manifest zone of Irian exists in Aerenal.

• Lamannia
  • Lamannia, the Twilight Forest, is a realm of raw unbounded nature. Untouched by civilization the realm is full of virgin forests, majestic mountains, rolling hills, steamy jungles, festering swamps, and all manner of terrain. Inhabited by all forms of plants, animals and magical beasts as well as a number of lycanthropes who have made a new life for themselves on the plane after fleeing Eberron during the time of the Silver Flame’s Purge. Regions of unspoiled nature flourish in times when Lamannia is coterminous with the Material Plane. Animals breed more prolifically and plants grow more verdant. When Lamannia is remote nature diminishes. Cultivated crops grow poorly and animals product small litters.

• Mabar
  • Mabar, the Endless Night, is a blackened realm where the faintest spark of light is quickly devoured by the unending darkness. It is a plane suffused with negative energy and is the antithesis of Irian. But, just like Irian, the energies of this plane work in opposition to the natural decay and birth of life, which makes a natural source for necromancers to draw power from.
    Negative energy spells are maximized and all the inhabitants of this plane are immune to effects from negative energy. Positive energy spells are impeded here. The nights grow blacker and more dangerous when Mabar becomes coterminous with the Material Plane. Travel to Mabar becomes as easy as stepping into an area where there is no light, and inhabitants of the plane slip out from the shadows and into the world. The plane becomes coterminous on three dark nights in the dead of night on the nights of the new moon closest to the winter solstice. Consequently when Mabar is remote the darkness seems to sap from Eberron. These periods occur every five years on the nights of the full moon around the summer solstice.

• Shavarath
  • Shavarath, the Battleground, is a region ever gripped in the throes of war as three groups vie for control of the plane: a host of celestial archons, an infernal regiment of devils, and a swarming horde of demons. Forever in a rough balance of power each of the three factions lay siege to one another’s fortresses only to lose their own holdings on other fortresses in the process. Beyond these fortresses the plain stretches infinitely, with low hills providing the only terrain feature. The plane is aligned by territory. Those areas held by the archons are mildly good and lawfully aligned while those areas held by devils are mildly evil and lawfully aligned and that held by the demons is mildly chaotic and evil aligned. Magic spells that mimic, create or enhance weapons as well as spells that excite hostile emotions are extended, while charms and pacifisms are impeded. Whirling blades travel the plane like flocks of birds seeking out non-native inhabitants and attacking them. In times of conflict, when Shavarath draws near to the Material Plane, the effects spill over into it. Magic spells are enhanced or impeded as they are on the Battleground and reports have even come of flocks of whirling blades seen on the battlefields. No known effect manifests when Shavarath is remote, but wizards theorize that it may coincide with times of peace.

• Syrania
  • Syrania, the Azure Sky, has the appearance of paradise, a weightless place maintained by angels. The floating cities drift in a crystalline blue sky ( thanks to the light gravity), each one governed by a powerful Solar. Sharn the city of towers is built in a Syrania manifest zone providing the city the ability to support the monstrous towers of the skyscraping metropolis. Clear blue cloudless skies and deep midnight blue skies mark a coterminous Syrania. When Syrania is remote the skies are slate gray or white and the nights are lightless and black. Sharn has a significant manifest zone of Syrania.