Long ago, in a time before thought, there was only a Globe in which all creation was mixed. As there was nothing with which to compare it, the globe was big and small, dark and bright, everything and nothing.
Over a hundred million years, the Globe began to grow and eventually two powers slowly began to form within. As they grew, the powers developed consciousness, becoming aware of their individuality, and separated into white light and darkness. White light formed as female and called itself Einhasad. The darkness formed as male and named itself Gran Kain.
Einhasad and Gran Kain joined their strength to break out of the Globe, which shattered into pieces of all kinds. Soon after that, they married. Out of this marriage there issued five children: the oldest daughter was Shilen, the oldest son was Pa'agrio. The second daughter was named Maphr, the fourth child, again a son, was Sayha. Their youngest daughter was named Eva.
Being the goddess of creation, Einhasad shaped from her spirit several forms, empty at first, from which her four older children, using their own powers, created life:
Shilen instilled the spirit of Water into the first form her mother had shaped. This is how the race of Elves was created.
Pa'agrio instilled the spirit of Fire into the second form his mother had shaped. This is how the race of Orcs was created.
Maphr instilled the spirit of Earth into the third form. This is how the race of Dwarves was created.
Sayha instilled the spirit of Wind into the fourth form. This is how the race of Arteias was created.
Inspired by Einhasad's work, her husband Gran Kain also wanted to create a race. Unfortunately their children had already given all the best essences to Einhasad, and all that was left over was the spirit of stagnant and rotten water, the spirit of dying fire, the spirit of barren and contaminated earth, and the spirit of wild and violent wind. From those ingredients Gran Kain created the Humans. Of course those creatures were weak, stupid, sly, and cowardly. All the other gods despised Gran Kain, and overcome by the shame of his failure, he abandoned his creation and went into hiding for a time.
Now an interesting thing happened. The races created by Einhasad quickly forgot about her and chose her children as protective deity. Orcs prayed to Pa'agrio, Dwarves to Maphr and so on. In the "Dwarf Creation Myth", a banned book now kept in the Arcane Library at Rune, it says "In the beginning there was the Great Creator Maphr ... With the help of Maphr the Dwarves were created, the race of the Earth. Maphr taught the Dwarves craftsmanship ...". In other words, Einhasad was not a factor to be reckoned with for the Dwarves, they barely ever mentioned her.
Not being worshipped any more is the worst thing that can happen to a deity. Gods live in the minds of people - if people don't think about them any more, they cease to exist. Einhasad urgently needed to do something. Trying to remind the races she had created that in fact she was their mother, that without the forms she had created, Orcs, Dwarves and all the others would never have come into existence, that would have been too much like whining for attention. So Einhasad adopted a different strategy. The Humans had been abandoned by Gran Kain in the wilderness, they had no way to communicate with their creator. Therefore they had developed a shamanistic religion that consisted in offering sacrifices to self-made gods of the Four Elements and worshiping their forefathers, conducting rites at their graves, imploring them to watch over their descendants. That was a situation Einhasad could make use of. When the Humans crowned Shunaiman, the leader of one of their clans, as emperor of the Elmoreden Empire, she sent down her daughter Anakim to give that enthronement her "divine blessing".
Being an extremely intelligent man, Shunaiman immediately seized the chance that was offered to him. He made Einhasad the patron deity of the new state, declaring her religion to be the only true faith while all other belief systems were denounced as heterodox cults, their adherents mercilessly persecuted. In all major towns of Elmore and Aden temples to Einhasad were built, with a statue of the goddess wielding her iconic sword in the back and the priests performing their rituals in front of her, under her eyes. Einhasad had given him political power, he gave Einhasad the worshipers she needed.
Having become the state religion, the Einhasad cult soon developed a momentum of its own. The clergy, keeping its lower ranks under control through a strict hierarchy, was on the side of the ruling class since the beginning, receiving their protection and donations, and indoctrinating the population in exchange, teaching the believers that the present feudal system was what the goddess wanted and approved of.
Of course not everybody shared that point of view. First of all there were the Children of Shilen, who refused to accept the blatant lie that mankind was not created by Gran Kain but by his wife. As a religious organization the Children of Shilen were subject to severe persecution, and most of them retired in the end to the continent of Gracia in the west. Their place was taken by the Revolutionary Army of Dusk, followers of Shilen who are waging a bloody war against the Lords of Dawn, as they call themselves, striving for the control of Shunaiman's Seals.
And there are also heretics within the Einhasad clergy, like for example Preacher Sla who has left Giran for the Plains of Dion where she has collected a considerable number of followers who want to reform the Einhasad Church, maybe not from within, but from the fringes.
 The Secret History of the Elmoreden Empire
 The Forbidden Book
 Jute's Bestiary