Disclaimer: I don't own any of Tolkien's or Riordan's work and if I did own both the rights I would rolling in enough money to fill a hobbit smial. This contains a butchering of the Greek creations myths in an effort to combine the two universes. Please leave feedback as how I can be more faithful to both.
The story of the creation of Arda is one many know well, but the story of the world of the Greek Gods and Goddesses is not well known. It actually begins in the same way the realm of the Valar and Morgoth and here is its tale.
Many talk of chaos and the void being where the beginnings of the Greek World and the world of Perseus Jackson. Here recorded is the true tale which only the wisest of Elves know and sing in the mountains of Valinor. Knowledge preserved since the Days of the Lamps before the marring of Arda.
In the beginning, Eru the One, who in the Elvish tongue is called Iluvatar, made the Ainur of his thought and they made a great music before him. In this music the world was begun, then those of the Ainur who desired it arose and entered into the world in the beginning of time. By their labors to fulfil the vision they had seen in the music Eru had brought forth, long they labored in the regions of Eä. Which are vast beyond the thought of Elves and men, until in the time appointed was made Arda. Then they put on its raiment and descended forth into.
But there are other worlds beyond the realm of the Maiar and The Rings of Power. Realms and worlds filled with creatures beyond imagining, and one such realm is that in which the adventures of the great Greek heros take place. This realm was created in the vastness of Eä along with the Arda and this name today is the Earth. It too was shaped by the Music of Ainur though the deities that now Rule there would not have you believe it.
The betrayal of Melkor is well documented by the Noldor who suffered the most because of him. The entire First Age and it's sorrows are largely his work. But often the songs of the Noldor leave out the two Ainur that stood with him in the beginning when he weaved the opposing music.
Before they became the two great deities that ruled the world inhabited only by the second children of Iluvatar, the figures known now as Ouranos and Gaia stood beside Melkor as he sang against the first and second themes. They too wished for the Flame Imperishable, the tool with which to create life. Unlike Melkor though, they did not search the Void for the Flame but instead became the loudest singers of Melkor's theme. Great wisdom, power, and other gifts had been bestowed upon them, but liken unto Melkor it made them eager for more.
When the time came when those that would become the Valar entered into Arda along with Melkor they stayed behind. For they desired the power of life and creation but were unwilling to share it with others. When they saw the war that had erupted when Melkor clashed with his former brothers and sisters they waited and watched. They waited for the awakening of the Elves but did not see in them the tools with which they wanted to build their kingdom.
With the awakening of the Second Children, men, the two grew fearful at their gift. For Iluvatar decreed that men would be his instruments and be beyond the Music and the Circles of the World. The Gift of Men which is to defy fate brought fear into the hearts of Gaea and Uranus. So they plotted to spirit the Second children away and so in their fear and arrogance attempted to take the race of men to a foreign and dangerous land.
For beyond Arda lay another world which was formless and shapeless among the vastness of Ea. So they went and left Iluvatar, binding Gaea to the earth and Uranus to the heavens of the place. These two were jealous of the gifts of their brother Manwaë and sisters Yavanna and Varda, and so made themselves in their likeness. Uranus the ruler of the skies and its stars, and Gaea the ruler of the earth. They would cow the second children into their bidding and they would rule over them as deities unquestioned. But Ulmo of the Valar, who is ever the friend of the Second Children, hindered this plan. He shielded many of the wandering tribes of men who awoke at Hildóien. As well as sundering the world of Gaea and Uranus so that ever after the realm of Gaea was covered in water.
Still the two they drew others to them like unto themselves who declared themselves their children, and these became the Titans. For as Ainur were drawn to Arda and the Valar or Morgoth the enemy. So too were spirits drawn to this world and to shape it in the visions they had seen. Others also came, great boisterous giants hewn of stone they appeared to men, but like all beings who once sang at Iluvatar's side their form was not limited by the physical.
Eventually power of the Titans grew and jealously festered in their hearts. So they cast down Uranus and put Gaea into slumber that has lasted for eons. They too ruled over the second children which they treated as pet and toys. For the fear of the second children was a common theme they all sung as Ainur and carried with them to Earth.
And so in their fear the Titans hollowed out the earth and created Hades, the Underworld. In likeness to the Halls of Mandos. Unlike the halls in Valinor however, these were made strong and in terror to hold in the spirits of men and prevent their exiting the Circles of this World. But it was not enough. Men spirits still left the world and sought beyond them, and the Titans sought contentment for the men. For in contentment is control, those restless are oft more eager to chance their lot amid the fortunes and chances of the world.
So in their desperation the Titans sought the three sisters, whose weavings were not unlike the Music they sang before Iluvatar. They asked of them a great task, to weave the fates of an entire world and all who lived in it so as to bind the souls of men specifically to the earth. The themselves would be bound to theses fates and submit themselves to them. If only for the purpose of binding the Second Children to fate. So the sisters wove cut and spun their silks in mockery of the Music.
It was also in this time at monsters began to appear under the order and dominion of Typhoon who is considered the father of these dark beasts. As the monsters of Morgoth were mockery of the creatures of the Valar so too were these. Terrible and treacherous they were. Similar to the spirits of the Maia they could not be their physical form could be diminished and slain, their spirit remained in the halls of Tartarus where all evil things in this world linger. To draw a comparison between the two it would be like the great dungeons of Angband and Utommo. Where creatures of darkness dwell innumerable and men are shackled and doomed never to see the light of the sun.
It was then new spirits came into the world of a new generation. Those that would later be known as Olympians ventured into the world and fought the Titans. The battle raged for years untold with the regions of the earth. Until at last the Olympians won and declared themselves rulers of the Earth and masters of it. They took on traits both noble and vile from Iluvatar's creation. To the point where they were like them in thought and emotion.
Still they feared the men under them and their gift. For all know that all creations across all time and space will one day be called to the Dagor Dagorath, and eventually Men's purpose and gift will set them even unto the level of the Ainur they once were. So the Olympians feared to give them power. Feared the freedom that humans should have.
The legend of Prometheus is one widely spread, of how he gave Men fire and from their they advanced. For he remembered the vision which he had seen when he too sang at the feet of Eru. That among all worlds Men would become great and dominate the land. So against the will of the Gods he set out and gave to the second children the instrument with which the great civilizations of the Greeks and Romans would later become. Punished most harshly for this act Promethetheus' heart would eventually become dark.
I'm sure many can guess all that happens next. The history of the human civilizations of the earth. A few even know the extent to which the world of Myths and Legends played in the shaping and forming of these things. But the story many know which has introduced them to this world is the tale of Percy Jackson.
Which brings us to the modern day where gods live above on the Empire State and below the Earth the souls of men are still trapped within the Circles of the World. The fates still spin the lives of all, contrasting with the Music and withholding the Gift of Men. The Gods allow this for they too are bound by the Fates which spin the lives of all beings of this world.
To break the hold of the Fates, it must be something of a world beyond the Earth that makes a change. And one must remember Eru's decree that Men shall be his primary instruments whether they use the Gift or good or ill. But that is another story, and there's little time for that now.
A/N This quick drabble was a way to make the worlds of Tolkien and Riordan blend, but there was no way to do that perfectly. I just liked the idea of everything coming from Iluvatar. I really want feedback on this and I might change it to better reflect both the Greek Myths and Tolkien's vision. This was a quick drabble done early in the morning so you'll forgive me if it's crap right? This is generally my excuse for how things are going to work in my future LotR/PJO crossover. So keep your eyes peeled for that.