Eidolon (aɪˈdoʊlɑn)
More than any other component, the eidolon is the closest to being the person as we think of them. - Callisthenes of Macris
As described in The Structure of the Universe, the world is made up of three realms - the Physical realm, The Dream realm, and The Spirit Realm. Likewise, all the things within the world have parts of themselves in each realm. The eidolon is The Dream body of creatures, the part of each thinking being which exists within The Dream.
The eidolon is the part of a person which contains their memories, experiences, personality and identity. After death, this is the only component of the person to retain these qualities. This causes many people to believe that this is the most important part of a person, although attempts at resurrection have shown that this is not quite true. You can read more about about what happens to an eidolon after death here.
Eidolons and The Egregoric Force
All things within The Dream are subject to the forces of collective belief, what we call the Egregoric Force. Eidolons are no exception to this, and can be shaped and distorted by the pressure of what other people believe about them. When an eidolon is anchored in the other Realms through association with a physical and spiritual body, it gains significant resistance to this force. However, when it is unanchored (by death or other means), this resistance is lost. The force of collective belief will shape the eidolon over time, remaking them into what others believed them to be. Their identity and memories can be completely transformed in this process, and those eidolons that persist long after death are frequently unreliable narrators of their own lives as a consequence. You can read more about the Egregoric Force and how it shapes the world here.
Apotheosis
The gods and spirits of this world (collectively known as Numina) are born of the Egregoric Force, and have their own eidolons that arose from the beliefs that created them. But not all gods are born from beliefs first. Sometimes, the eidolon of a living person becomes the seed for a new god, carrying their memories and identity into a new entity based on the original. This process is known as apotheosis.
This new god is not exactly a continuation of the person that was there before. A person is a combination of their physical, dream, and spirit bodies, and changing out any one of these results in a new person who may or may not resemble the old one. During apotheosis, the eidolon will acquire new anchors in the physical and spirit realms, a process which can take years. During this time, the pressure of the Egregoric Force is forcing the eidolon to conform with the beliefs held about the person they once were. In the end, the Numina that is born is often a simplified version of the original person who is consistent with the beliefs held about them. You can read more about Numina here.
Aggregate Eidolons
Over time, the Egregoric Force can erode the individuality of an eidolon, erasing most or all of the details of their personal life. What remains after this is done is more of an archetype than the memory of a particular person, and will tend to merge together into an aggregate entity that contains only those elements that survived the corrosive process. One example of a aggregate eidolon is Zai, the god of Gailur Altua on the island of Irlandia. Zai is the aggregate eidolon of the Herrian royal family, and patron of the Kingdom of Herria. Zai is not the eidolon of any particular member of the family, but contains memories and experiences from a host of former people.
Preserving Eidolons
Not all eidolons are destined to be warped and eroded by the Egregoric Force. The Clarati sorcerer Clarion was deeply interested in the Eidolon and how it could be insulated from these changes, and made it a focus of his studies. While in the Biluzik Archipelago, he observed eidolons anchoring themselves to the stones used to mark their graves in the royal cemetary on Gailur Altua, which permitted them to preserve much of their memories (although they would still merge into the aggregate god Zai). He was inspired by this to create Petrified Eidolons, which lock the memory and identity of a deceased person into stone. These eidolons are preserved from any and all changes, at least as long as the stone remains. You can read more about them here.
A Note on Terms
In this article I am using the terms popularized by Callisthenes of Macris and derived from the Kaphtorikós language. Other languages around the Great Ring use different terms for these concepts.
Crumbling Under Pressure
While being anchored to a physical and spiritual body grants an eidolon significant resistance to the Egregoric Force, it does not make it immune to the pressures of collective belief. In some cases, these pressures will overwhelm this resistance, resulting in a condition known as Dissolutio Identitatis. You can read more about this degenerative condition here.
Are You Still Here?
There are places in the world where the local conditions (as created by Folk Magic) result in many more eidolons hanging around after death. In these locations, the eidolons of the dead frequently interact with the living, for better and worse. One place where this happens is the Biluzik Archipelago, where those who have passed on frequently fail to pass very far from the living world. You can explore more about the Biluzik Archipelago here.
Living Apotheosis
In theory, one does not need to die in order to experience apotheosis. If there is enough belief about a person, that can transform a living being into one of the Numina, anchored to their living body and original pneuma, but gaining the powers and spiritual presence of a god.
In practice, it is nearly impossible for this to happen, and not a pleasant process to undergo. It is a possible end result of Dissolutio Identitatis, and thus means that the personality and identity of the being undergoing apotheosis is irrevocably altered and simplified. There is only one example of living apotheosis ever recorded, which is that of the gargantuan turtle (and pirate haven) known as Tortuka. You can read more about this creature here.
'Their identity and memories can be completely transformed in this process, and those eidolons that persist long after death are frequently unreliable narrators of their own lives as a consequence.' This is so fascinating. I feel like you can see this happening to people in history by the way they are remembered. I like the idea of petrified eidolons too. :)
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Thanks! I got the idea while watching a performance of Faustus, when he summoned Helen of Troy; I imagined how surprised he’d be if an actual historical figure appeared, and that led me down the path to eidolons morphing based on beliefs about them. It was one of the key moments that led to the structure of this setting. ;)