[A/N:Also another thing about Valyria will have gods that are modeled after Egyptian gods and Greek gods, they will be similar to the versions from the movie gods of Egypt.I don't mow if this is good idea or not.]
The war started the Children possess strong magic powers and with giants by their side they were not easy to defeat .But the First Men were better armed with bronze weapons, and simply more numerous.
Children of the forest started losing number in the wars, so they prayed to the Ancient gods and Eru and which was answered as Eru gave them blessing, which resulted in there magical powers getting a boost.
The Children of the Forest use their magic to call down the Hammer of the waters, destroying the Arm of Dorne and creating the island chain known as the Stepstones. Destroying the land bridge prevent more humans from crossing to the continent on foot, but there are already far too many in southern Westeros to stop.
Also during the time Yavanna also helped them by preventing many of the children of the forest from getting killed by providing help.Which was really appreciated.
Eventually the Children of the Forest call down the Hammer of the waters a second time, to try to split Westeros in two (and retreat to the northern half), but this time they only succeed in flooding the Neck, transforming its fields into swamps and bogs.
During this time Children of the forest in panicked and becoming desperate because unlike first men they didn't have huge numbers.So they created the Night King.
But by the time years of warfare had caused, the two sides agree to a truce: the Children could not win, but the First Men feared thy same believing they would lose if they continued to fight the Children to extinction. Wiser heads prevailed, and so the Children and First Men made the Pact on the Isle of Faces: the First Men took control of the open lands and the Children took control of the forested interiors.
The children of forest removed there plans about the night king, they slowly taught the first men there first writings and since they written records were kept.
In time, the First Men adopt the worship of the Old Gods of the Forest.There was peace until the Long night.
Eru who watching everything from the void"So it begins."
Yavanna saw there something dark about the Night King and it looked at everything with hate and her thoughts became reality, when Night Kinng turned on the Children of the Forest and wanted everything living to die.
Yavanna was worried questioned"Are we going to help them?"
Eru shook his head and answered"We will help them, but not now they must know choices have consequences."
Yavanna was sad seeing children of forest get attacked by Night king.
But Ulmo agreed with his father and added"They made a mistake and they have fix it themselves, if we correct it for them.Which may lead to them neverinf understanding the consequences."
Yavanna slightly nodded and asked"But can we advise or warn them?"
Eru nodded, which gave her hope they will get out of this alive.
While Eru, Yavanna and Ulmo went to meet the Children of Forest responsible for the cause of the Night Kings creation they begged the ancient gods for forgiveness.
In a flash of light all of them appeared before the children of forest, who were happy and guilty.Leaf filled with courage told the Eru"Creator,we made a mistake."
Eru nodded"I warned you multiple times that your choices with have consequences....Also nothing good would have come by playing with such dark rituals."
All of them bowed their head apologized profusely.
Eru spoke up"Go and warn the first men and join forces with them, since you created this being it is your duty to kill it and so we will give you the tools necessary to combat them."
Children of forest agreed and they were given information about dragon glass being the night king and white walkers weakness, also they quickly warned the first men about the incoming darkness.Eru also provided them with a captured walker.
Eru the whispered "The first men need a leader....someone strong and with really powerful magic in them."
While Yavanna questioned"Have you found one father?"
Eru smiled and seeing the famous Azor Azai.Who was a man from east, he settled down in westeros with his wife and Eru decided to to visit him.
Now another issue he wanted to talk about was Ulmo's water benders in Essos, so he turned to Ulmo and asked"So what about your followers?"
Ulmo gave smiled and replied"There influence and power has been growing over the years and have established themselves."
Eru nodded, he heard Ulmo explain about how his followers call themselves Water priest or priestess.How there nature of healing led them to be more accepted than followers of R'hollar, but water clan was also able to show they are not to be messed with too when threatened.A whole group of R'hollar followers were encased in ice and made into sculptures for everyone to see as an example.
Eru mutterd"That's good."
Ulmo added"There some like a growing civilization by the Rhoyne river that have accepted it and are now praying to us, I have blessed them too."
This was the great civilization of Rhyonar, who would later move to Dorne.
Ulmo the told his father that on the eastern continent of Essos, the ancient Ghiscari Empire was flourishing on the eastern coast of Slaver's Bay, one of the oldest - if not the oldest - great civilizations in the world. The Ghiscari Empire is built on large-scale slavery of conquered peoples, who toil away to build the great pyramids of Old Ghis and its colonies.
Eru smiled and said"Everything is moving in place."
He turned to Ulmo and added"Keep an eye on Rhyonar and those Red priests/priestess."
Ulmo nodded, while Yavanna questioned"What about Lion of high from Yi Ti?"
Eru waved it off and answered"He is no threat."
Yavanna nodded letting it go.