The extremely abridged version, according to all my theories and our known facts:
Before the beginning of the world, there was a planet ruled by the Old (or "Dark") Gods. Then some new gods, Wyrd and Nyx, showed up. Wyrd woke up from the One Dream, and set about creating what he saw in it on the planet below. This is the known world. Nyx, for some reason, fought with him about this time, and created Tharsis on his world. She also created the Trow to dominate it. The Dark Gods felt betrayed and killed Wyrd' son Segoth, beheading him and preserving his life and power of speech. They later shattered the One Dream. The Dark Gods may also be the Spider Gods, in which case they wound up in another dimension, or perhaps they already lived there.
The Trow dominated the known world, and every thousand years another race would come to challenge them, perhaps sent by the Dark Gods or The Leveller. But the Trow always prevailed. The last of these races were the Callieach. The Callieach may be from the Spider-world, avataras of the Spider Gods or somesuch. Either way, they were insanely powerfull magicians who almost bested the Trow, but the Trow cornered them in the Valley of the Red Seal, where they killed themselves and many Trow creating the Great Devoid, which may lead back to the Spider-world.
An aeon of peace for the Trow followed, until the Younger Races (Oghres, humans, Dwarves, fir'Bolg, etc) appeared. They expanded in the shadow of the Trow empire. Meanwhile, a cycle of Light and Dark had started amongst the humans. In 1570 HC, the First Era began. A transient divinity called the Leveller inhabited a man in the east, who we shall call "B", and made him try to take over the world. Another man, who we shall call "A", arose in the west to oppose him, but failed. B, however, died anyway. A comet rose in the east, and Tharsis erupted. A thousand years of darkness followed.
At the end of this thousand years, A and B were reincarnated. The Leveller took over B again, and he came from the west to destroy the world. A, however, now called Tireces, prevailed. B was immobilized by sorcery, beheaded, and burnt at the stake. A comet rose in the west, and Tharsis erupted. A thousand years of Light, called the Age of Reason, followed. Tireces founded the city of Llancarfan, then disappeared. 570 years later, Clovis founded the Cath Bruig empire, and renamed Llancarfan to Muirthemne. Near the end of this era, the Oghres insulted the Trow, and were enslaved by them.
In 431 AE, the Third Era, or Wind Age, began. Tireces returned from the east as Moagim, the Leveller. B was reincarnated in the west, and died trying to oppose Moagim and his Myrkridia. He did manage to ensure Moagim's defeat, but nevertheless a thousand years of darkness followed. A comet rose in the east, and Tharsis erupted. Near the end of this era, the Oghres rebelled against the Trow, and were exterminated in a long battle at the Valley of the Red Seal.
In 1431 AE, the Fourth Era began. B was reincarnated in the east as Connacht, and went about destroying the Myrkridia. He comissioned the Tain to be built by the Smiths of Muirthemne, Dwarven sorceror-engineers, and use it to imprison the Myrkridia in a realm between ours and that of the Spider-gods. Then he turned to the Trow, who had abandoned iron in shame after exterminating the Oghres, and imprisoned them beneath their own cities. At this time, Moagim was reincarnated in the west as "Moagim Reborn" and tried to (you guessed it) take over the world again, what with that Leveller spirit and all, but Connacht was too much of a badass and killed him again. Then Connacht tried to break the cycle forever by hiding all sorts of magic artifacts and such, but felt he hadn't done enough and disappeared.
In 2431 AE, he returned as Balor, the Leveller, and began to lay waste to the world. He freed the Trow, summoned the Fetch from the Spider-world, and gathered together all sorts of nasties. Tireces/Moagim was reincarnated again in the west as Alric, and though a little late, set out on his futile quest to defeat Balor.
Except he won! With the aid of a severed head now believed to be Wyrd's son Segoth, the Light's last stand wasn't their last after all. The tides of war turned, and Balor was defeated. Fifty years late, a comet rose in the east and Tharsis erupted. Sixty years of peace followed, after which Balor's general Soulblighter returned. He again set out to destroy the world, and came very close, but Alric was just too powerfull for him.
As GURPS says, a hard-earned peace seems the immediate outlook, if you can overlook one simple fact.
It wasn't the Light's turn to win.
