Deities of the Mythos

Who trusts those who split the realms?

Deities:
The One True Power – Unknown and spoken only through rumors and vague mythos. Not even the oldest and wisest of seers can grasp the form or potential of the one true power. Whether it is a being, force of reality, or something else undefined is unclear.
Upper Deities:
Primordials – Supposed elemental embodiment of the one true power, comprised of the elements of being. They shaped the realms and created realms by the formation of their respective elements.
Named as follows:

Pneumos, Hydros, Pyros

Lithos, Metallum, Lux

Tenebris, Fulgur, Psynos

Thorn – The primordial dragon who created dragons as they appear through the mythos. Immortal to age, and existed to protect the primordial elementals, who were to watch over the realms. After the realms split, Thorn divided his being into the great dragons, who subdivided into the lesser dragons, for the individual realms to be watched over. Now it is said that Thorn lies in slumber until his splintered selves return and rejoin with him.
Fate – Known as a white ghostly paternal woman with glowing blue eyes, and a bright engulfing aura. She manifests the course of destiny for the temporal plane. It is believed that she betrayed the elementals and is partially responsible for the splitting of the realms.
Death – Known as a dark, but sanguine skeleton with a clouded robe, and an icy cane. Executes the course of fate, and keeps the balance of life. With the absence of death, the natural order would vanish. Betrayed the elementals and is partially responsible for the splitting of the realms.
Lower Deities:
Mana Eaters – Horrifying abominations whose existence threatens reality and the deities.
Great Dragons - The immediate spawn of Thorn, created to watch over the realms. Aside from Thorn, they are the only other dragons to possess wings.
Realm Masters – Powerful beings who have occupied a realm beyond the control of the lesser dragons, who have equal propensity for being benign, or cruelty and wanton destruction.
Ascended Common
Lesser Dragons - The spawn of the great dragons, which are most likely to interact with humanity. Without wings, and the current absence of Thorn, they are viewed as abhorrent.
Heroes - The humanoids who have ascended to great power in their lifespans. They have harnessed powerful energy beyond the capability of conventional mortals.
Adventurers – The humanoids who are determined to beat their own path, committing their lives and limbs to the search of enlightenment, status, power, or wealth.
Common
Humanoids – They are the subjugated and victims of the splitting of the realms. Their role was to shape the realms through magicka, but lost their role, and now follow the direction of fate.

Summary

The prevailing belief is that the One True Power created the primordials to shape its realm. Thorn the primordial dragon coexisted along them to see their creation through and protect the creation.
The realms were formed, humanoids were created of varying shapes and sizes in order to see the finality of the realms be created through magicka, existing in the joined realms.
Eventually, Fate and Death, who were supposed to protect and maintain humanity, betrayed the realm system and the current reality. It is said that their understanding of the future took precedence of the realms. They fought with the primordials when Thorn was away and through the conflict, broke the realm system, allowing the leftovers from creation to flood the space between realms.
With the primordials gone and Thorn's essence split to keep the dismembered realms relatively safe, there was no entity left to watch over the humanoids. The humanoids were taken in by fate to have their destinies consolidated with her will.
More recently, in the power vacuum, the realm masters and mana eaters have taken to the temporal and incorporeal existences respectively.

Historical Basis

It is said that relics of the past, though decrepit and worn, are the main key in understanding the present, and by extension, the future. No current scripts prove the existence of the splitting of the realms. Mythos are the only source of documentation regarding the realms' history, which is often rebutted by seers who see opposing visions. The only true way to know would be to access an artifact, and to see the sunder firsthand.