Spirit World

The Spirit Realm (also known as The Spirit World) is an incorporeal dimension parallel to the physical plane  of Eternia where Spirits and other supernatural creatures reside. When a creature dies, they're said to pass into the Spirit World for an unspecified amount of time.

There are only a few known methods to enter the Spirit Realm, with one of them being the use of Rift Magic, a ritual that allows those involved to astral project as spirits, entering the lifestream and passing into the Spirit World may also be used. However, leaving the Spirit Realm is considerably easier - it is commonplace for wandering spirits to enter the physical world.

Characteristics
The Spirit Realm operates on a different set of rules than the physical world. The world is seemingly infinite in every direction, geographies vary radically and often morph on whim, and gravity is not always constant. A common sight in the Spirit Realm is the physical manifest of the lifestream in the form of tangible, spiraling streams of energy gliding around landscapes and horizons. Stars may be identified by locating points of great spiritual energy, often where points in the lifestream intersect.

The realm is populated by both humanoid and non-humanoid spirits. Human spirits are usually spectral images of bygone souls, bound to the physical world by unresolved strife or internal anguish.

Realms
While seemingly infinite in scope and with a maze-like geography that's constantly changing, the Spirit World is defined by eight realms. These are:

Yggdrasil, Tree of Convergence
The centre of the Spirit World where the flow of life-stream ultimately meets, weaving up against a trunk several miles tall. Its leaves shimmer brilliantly, primarily in silvery blues and greens. The spirits of fae nest here, with newborns being produced from within the Great Tree before springing to life in the physical realm. The Angel Thediel theorised that fae often companion with humans with good intentions because of the conditions they're born under: "They know the lifestream and its complexities, its in their soul. And to know the lifestream is to know the heart of man."

Vanaheim, Realm of the Exalted
The realm closest to Yggdrasil, and also the smallest. Nigh-impenetrable silver walls surround it and the tree, and the city itself is something out of a dream, surpassing any man-made structure. An essence may be permitted to enter if they've accomplished great deeds within their lifetime. The creature entrusted with the governance of this realm is known as the Overseer.

Joruheim, Realm of the Brave
On the outskirts of  Vanaheim's great wall is Joruheim, a large realm made up of sixteen city-states with the Gods of Uray as the acting idols. The essences of warriors that lived and died by a code often find themselves wandering here, with Joruheim's occupants mostly being made up of Wardens;  the rangers of the Spirit World, tasked with protecting the borders of the other realms and enforcing the laws, as well as aiding in the protection of Vanaheim if need be.

Helheim, Realm of the Lost
An essence burdened by its actions in life will often unknowingly wander toward the borders of Helheim. The edges of the realm are bare and dry, the spiralling streams of life energy found within the Spirit World almost non-existent here. The deeper one ventures the colder it becomes, and the less likely they are to turn back as their guilt seems to entice them to keep moving.

The largest realm in the Spirit World is governed by the the Nethradin, demonic spirits that often torment the unfortunate. If an essence is able to overcome these troublesome creatures, they may realize the courage to escape Helheim. The Nethradin themselves were once the same burdened spirits that failed to escape and eventually lost the memories of who they were, changing their form.

The Lord of Spirits, Ryujin, chose a Nethradin to govern the rest, granting them the title of Shaytan. Since then however the title has switched hands several times, either through force or a successor. Even Ryujin is wary of the realm and unable to contain it, leaving them to their own devices and entrusting the other realms to remain vigilant. As of 1029AC, the Shaytan in power is Daeva the Infallible, successor to Aeshma of Sin in 925AC. Daeva has been exceptionally bold compared to his predecessors, going as far as to raid and conquer parts of Alfheim and Ifraheim, expanding the desolate borders of his domain.

Beneath the Shaytan the Marquis are bestowed land and resources. The Marquis are often as dangerous as the Shaytan themselves. Currently there are five, including a nameless hellhound that resides within the Shaytan's fortress. The hellhound is rumored to be Grigori; a powerful Nethradin that challenged Daeva directly and was bound to the form of a beast as punishment and a means of control.

The long river Styx crosses through most of Helheim. The faces of those desperate enough to contract with a demon can be seen beneath the waters, as well as the fallen essence's that chose to drown themselves in the river rather than seek redemption. The Marquis Sitri is a lizard-like creature that dwells within the Styx, his lands to either side of the river.

Alfheim, Realm of the Meek
Alfheim is one of the biggest realms within the Spirit Realm, the lands in which the non-magi spirits go in death. It is a place of peace and recovery, where the less powerful essences go in death.

The land itself is that of a calm pastoral scene, a relaxing land of endless hilly grasslands and warm winds. To some, it could be seen as a paradise, the rains and cooling winds from Uraheim balanced with the drifting heat from Infraheim, underlied by the calm, neutral stability of Terraheim.

Small villages and settlements of spirits that once were common farmers, craftsmen, peasants and other regular folk exist within this realm, honoring the Wardens of Joruheim who protect them, and living out modest lives much as they did in life.

Uraheim, Land of Water
Uraheim is a land of ice and water, the cold to Infraheim’s hot. Great land-masses of ice cover the Land of Water, while spirits of the ocean and its denizens live under the surface.

Ifraheim, Land of Flame
The idol Ifrit is said to dwell within this realm. Their companion is a phoenix and they wield a whip that scorches the land with each strike. Ifrit is one of the most revered idols on the physical plane... notably, several tribes within Gehenna worship them, and those that do so are granted Flame of Ifrit, an undying fire that conjures itself upon the wielder's weapon and empowers their magic. Ifrit was said to have clashed and almost kill Aeshma of Sin on the outskirts of Ifraheim, leading to the latter stepping down as Shaytan of Helheim.

In Huitzilopochtlism scripture, the sun palace is said to be located here.

Terraheim, Land of Mountain
Terraheim is a neutral, craggy realm that borders both Infraheim and Uraheim, giving balance to each by acting as a border. It is the land of elemental earth, the stability that grants form and resists the movement of air and the acceleration of lightning, while preventing the boiling realm of Infraheim and the icy realm of Uraheim from crossing into one another.

This land is a temperate balance of the forces, the endless rock containing minerals such as soul steel, which is said to help keep the Spirit Realm itself stable.

The spirits here of those of balance and compromise. To take something requires something else to be given in its place.

Divine Spirit
The spirit gods that helped to create the world. Each is the avatar of a particular aspect of Eternia.

Idol
Exalted spirits that govern a region in the spirit world; sometimes they amass followings in the physical realm, such as is the case with the Urayan Gods. They are known to sometimes commune and even advise humans.

Essence
A human spirit.

Elemental
For every river, mountain, etc, there's an elemental in the spirit world. While these are unseen in the living realm (unless a person has abilities that allow them to do so) these greater elementals are the 'spiritual' aspect of the physical.

Wisp
Small, lesser spirits. The spirits of most animals become wisps on death.

Nethradin
Nethradin are corrupted Esssence spirits, often after spending many years in Helheim. Some scholars believe that demons are Nethradin that slip through the cracks of the spiritual realm when a sleeping human has a nightmare (perhaps causing sleep paralysis or even death).