The Astral Barrier

After the events of the Great Shatter, the world which has become known as The Shattered Isles has become cut off from most if not all of the outer planes, and its connections to the Inner Planes are strained and offer only limited travel options. The cause of this continued separation is a metaphysical structure called the Astral Barrier by those who study it. The Astral Barrier has been described as an egg-like structure by some people, with the few known portals working as "cracks" in the "shell" that surrounds the world. It is believed that should enough portals, naturally occurring ones as well as the World Gates of the Old World, were to be opened continuously the Astral Barrier would be sundered and the world would fully re-connect with the Outer Planes and the wider multiverse. The advantages and disadvantages of this are hotly debated by many people, as the world does benefit from the Astral Barrier as well as has drawbacks.

Natural Portals:

Natural portals are scattered throughout the world; locating them is often the most difficult, as many of these portal sites move around the world unless tied to a singular Place of Power. Traversing them is not much easier, as more often than not they are one-way, leading into the isles rather than going out of them. Most often these natural portals are limited to releasing inanimate objects. The deadly rogue storms many sailors have encountered are attributed to natural portals to the plane of Elemental Air spewing out great winds and rains, summoning elementals and drawing storm-runners. Others have led to the creation of environments similar to those of other planes; noxious swamps connected the the Shadowfell or massive forests connected to the Feywild; eternal magma flows from the Plane of Fire and flowing rivers from the Plane of Water. Sometimes creatures native to these other planes come through, but most often they are elemental creatures who reform after transit. With enough magical power or the right knowledge, these Natural Portals can be stabilized, allowing passage back to their plane of origin from the Isles.

Plane Gates:

Plane gates are large structures created in the Old World. They cannot be built in modern times, as the knowledge to create them was lost alongside the ruin of many Plane Gates. These structures were the Old World's most reliable means of traversing between the planes, especially the outer planes. While these structures have been lost and many believed to be destroyed, the faint connection to some of the Outer Planes which wizards have detected makes explorers believe that there must be some Plane Gates that have been deactivated but still functional. Finding and reactivating these gates are believed to be the key to sundering the Astral Barrier and re-connecting the Shattered Isles to the Outer Planes and the powers of old.

World "Bubbles":

While the Astral Barrier is a structure that makes most plane travel impossible, the barrier can be "pushed" to create a bubble in the structure. While this "pushing" does not create cracks in the barrier, it does allow powerful individuals to create small demi planes and pocket dimensions within the barrier. Supernatural beings, particularly the Aspects and some Fragments have been known to create their own realms within the Barrier. Sufficiently powerful spellcasters are also able to create their own "bubbles" to serve whatever purpose they desire. When spells such as Banishment are cast, if there is no way for a supernatural creature to be sent back to their plane of origin, they are put in one of these "Bubbles" until the spell ends, at which point they are sent back to the Isles.

The Ethereal Plane:

The Ethereal Plane is the furthest point that any normal teleportation magic can reach in the Shattered Isles. Where the line is drawn between the Astral Barrier and the Ethereal Plane is debated, with some saying they are one and the same while others thing the deepest regions of the Ethereal Plane are where the Astral Barrier is found. It is theorized that going deep enough into the Ethereal Plane would allow an explorer to slip through the Astral Barrier where it is thinnest.
 
Some divine figures, mainly those charged with ferrying the souls of the dead, seem to be able to bring the souls of the dead to the edge of the Ethereal Plane to release them from the Isles. Weather these souls are truly brought beyond the Barrier or if these entities have created a large "Bubble" for souls to rest has never been confirmed, as spells such as Speak with Dead to not allow the caster to learn what exists after death.

Type

Metaphysical, Astral