"And lo, X'OL smote the Leviathans, casting them down from their high places into the depths the Abyss..."
Having cast the Leviathans into the depths of the Abyss, KOL set a guard to watch over the entrance to that dread place.
The crown of KOL's creation, the Anunna, or dragons, as they are now seen, came into the world.
The Dragons established and creation stabilized, X'OL, KOL Creator, departed this known universe for places unknown.
Though death had existed prior, Death, that is, true Death, from which few if any might return, did not exist in the First Forgotten Age. Those Anunna who passed were to be born again into new bodies, progressing as their physical forms evolved even as they continued to learn and progress personally and spiritually. But the Leviathans corrupted this, drawing instead a universe of souls into the Abyss, giving rise to the demons, slowly stretching the Abyss deeper and deeper, and slowly straining the seal of their prison...
From the seas they arose, the Mind-Lords of Unknowable Depths, and of the Anunna slaves they made.
The gods strained, the dragons bound, the world enslaved, the passage of souls into the Abyss tore open the gates of the Leviathan prison, and they began to set out from there to devour the world and make chaos of its remnants--beginning, naturally, with their servants deep in the Abyss...
Before He harrowed the Abyss, X'IS changed the system of death which had enabled the Leviathans to breach the Temporal Pavilion. Rather than recycling souls as originally designed, drawing souls to the Abyss as corrupted by the Leviathans, the new system would draw all souls (eventually) to be at the side of KOL as he and they remade the world.
With X'IS trapped deep in the Abyss, X'OL still absent, and only X'IM, Kol's sustaining spirit still remaining in the world, the angels, now the gods, partitioned the heavens, dividing its domains of power between themselves. Concerned that Kol's new system may draw souls to be trapped in the Abyss alongside him, they remade the system of death once more. Now, souls would go to the planes which most suited them upon their death, that they might gather a great host and relieve X'IS in some future Third Harrowing of Hell.
From the time of the First Harrowing, the Powers that Be and the Anunna sought to create ensouled beings perfect for a renewed harrowing of hell. With Mortals, they found such a being: intelligent, tool-adept, and possessing a morality conducive to their intended role. From then on poured out the numerous mortal races: orc and man and elf and dwarf, each to have a role to play in the harrowing and in the world to come. All that was needed was a little more time...
The most ancient legends of dragon and giant-kind speak of a great war between them, which brought to an end each of their ancient powers.
The wars of Chaos strained the barriers between the Abyss and the other planes of the Temporal Pavilion. As demons surged across the planes of the heavens, the Powers that Be found themselves once again at total war. This war prevented them from coming to the aid of the Anunna as the elves slowly began to win their war.
After some quarter million years of war, the elves at last defeated the dragons in their capital of Uršhumgallu
Some Eldar mythos hold that, at the height of their power, the Eldar forgot their ancient ways and their ancient gods, and instead their hearts turned to decadence. Other, more mainstream Eldar priests place the blame squarely at the feet of their ancient foe, Gathamuriel. Regardless, both hold that at dawn, on the first day of the five-hundred-thousandth year of the empire, great gouts of flame poured down from heaven and burned away the works of Eldar hands.
In 225, a group of powerful Nordric warriors and skalds known as the Aesir defeated their ancient frost giant enemies in a truly humiliating manner. By some forbidden secrets, they determined how to undergo apotheosis--and how to rob their enemy's gods of their domains in the process. The frost giant gods were slain, and the Nords now had direct access to powerful gods.
Starting in 2316, the Aesir fought a protracted war with a group of might Nordric champions who attempted to overthrow them as the Aesir had the Frost Giant gods long ago.
Demonic Invasion of Vorsak occurs, driven by a magical accident.
Purposefully caused by a vengeful Vorsak mage.