It is expected that the work will come out incomplete, so feel free to point out all the mistakes and contradictions you can find.
Chapter I: Hearth and Dream
From time before time there were two worlds: The world of real now known as Hearth and the world of un-real, the world of possibilities that have not yet came true, from which all the life and magic comes, called Dream. The two worlds are separate yet connected. The first and most important connection is the infinitely spiraling River of Time, existing both in the Hearth and in the Dream. As the River flows possibility inevitably becomes reality, and reality dissolves into oblivion, becoming part of the Dream. It is by the River of Time the Creator entered the Hearth.
Chapter II: The Creator's touch
The earliest period of the Hearth history known is the Gemstone stage. It is said that all the Hearth once was a perfect gemstone, clear and pure, until eventually it got ground into different rocks and minerals by Time itself. These rocks soon became roots of the oldest mountains. This was the time when the Creator came into Hearth. About Creator it is only known that they were entity of great power, unclear motives and a desire to shape Hearth in their image.
First thing they took out of the pile of rocks that were currently Hearth a single silver nugget and made it into a some that is now the Firmament of Hearth. Then, they created the Sun that was the first fire known to Hearth, and it was so bright ant hot, it pierced through the Dream barrier and came into the un-real as a little everlasting fire. Creator hung the sun on top of the firmament to light it and the Hearth constantly. At this point the sun didn't yet revolve around the Hearth, but burned it's surface with their presence constantly and it is known to be the last thing Creator did before Old Gods.
Meanwhile in the underground rocks came to life, or, to say correctly, life came to rocks. Influenced by the Dream, warmed by the Sun they twisted, changed into new, more suitable for action forms. This is how trolls and oozes were created - a life as energetic as mountain itself: aeons pass, but a single troll may be seeing the same dream till this day from the day the Old Gods were born. Now only them and the mountain roots remember of that time.
Chapter III: Of origin and nature of the Old Gods
The Old Gods are either children or creations of the Creator. They may very well be the Creator themselves, divided into multiple equal entities acting as one. The Old Gods share with their predecessor strong connection with the Dream, incredible power, wild interest in Hearth's potential, ability and ambition to shape the world as they please.
However there are differences between them and the Creator:
-There's multiple of them, which means they can act in many different places at the same time;
-They are corporeal: Each Old God has a body of ash, stone, metal and fire;
-Their motives are somewhat clear: when Old Gods first glanced at the Hearth, the spark of curiosity ignited in their eyes, which then lead to all Hearth being 'lit';
-They are able to breathe life into things and use this ability constantly.
Not in a single line of folklore texts, one Old God is mentioned separately from the others: if one God smiles, all of them smile; each and every act of creation in committed by all Gods together. This makes the question "How many Old Gods are there?" irrelevant, since no matter the number, their goals, thoughts and actions are shared.
Chapter IV: The Old Gods' exploration and the World Seed
As previously said, when Old Gods were still young, they got curious about the Heath, it's wonders and potential. They made themselves chariots of ash and bronze and traveled distances beyond reckon. Every inch of this world became known to Gods and even though it was vast, it was empty and boring for their taste. So they came up with a plan. A plan to change Hearth forever, to lit it with flames of Life.
It were the Old Gods, who performed an unprecedented act: directly out of the Dream they pulled out an item, that did not exist before, a specific item that matched their goals perfectly. Out of nothing they created the World Seed and planted it in the Hearth ground.
The Seed sprouted and thus the Hearth was lit.
Chapter V: It grows.
The Seed was planted, yes, but it was only the beginning of God's great work of Creation. The sprout was still weak and the unforgiving light of Sun could wither it quickly, if Gods decided to leave it on it's own. To cover their plant from deadly rays, they took black nacre grown in River of Time and cut a dome out of it, the one that we now call the nightsky.
This gave the Sprout enough time to grow it's first buds, but the trouble wasn't over just yet.
The Sun burned mercilessly and, given enough time, was able to burn a hole through the dome. The Sprout was at brink of existence once again. The Old Gods raged as they saw their work go to waste. From the River of Time they raised the smallest pearl and with all their rage threw it at the sun.
High in the sky Sun noticed an object flying towards at an incredible speed. The closer it got, the more sun felt divine wrath radiating from approaching missle. Of course, Sun was very powerful itself, but, as it realized, not powerful enough to survive this furious hit. The Sun had to move to not get shattered and so it did, for the first time since being created. When the thrown pearl reached the nightsky, it got stuck in the hole sun burned through the dome. But the pearl, filled with God's anger and own desire to reach it's destination, raised the nightsky and raced towards the sun with it. Till this very day, the chase continues. This is how Moon, the first strider, was created.
Finally the sun wasn't a threat to the Sprout and it started to grow it's first leaves. But, being planted on bare stones, it couldn't grow further and leaves very soon went dry. To resolve this threat, a giant earthware dish was fired by the Old Gods in the Sun's fire and filled with waters of the River of Time. Then the heavy dish was put into the landscape of Hearth and scratched rivers in the ground to the Plant's roots. That dish we now know as the Ocean.
Chapter VI: Hearthlings and the World Tree
Now, as the Sprout had all means to flourish, it grew wider and wider, stronger and stronger until eventually all of the Hearth was covered in World Tree. Countless spirits came down it's branches and up it's roots. From the Tree they took various animal forms, swimming, flying, running, crawling, slithering. The strongest of them regained the most connection with the Dream, becoming woodland spirits. The ones that possessed the World Tree fruits, emerged as powerful dragons, only to be chained by Old Gods to the edge of the Hearth.
When the first animals came to life, the Old Gods gathered a mighty herd, raised it high above the sky and let it run across the firmament. And where their hooves stood, the stars were ignited.
The Hearth was full of life, beautiful yet fragile. It was no place for Old Gods' blazing nature anymore.
The Old Gods knew they had to leave this world soon, but didn't want to lose control over it completely. They needed someone, who would represent their ambitions in this world, their desire to change it. Someone who would come into this world weak enough to not destroy it instantly, but regain power above all living creatures on Hearth with time.
Out of the white clay the body was fired, out of the red clay the blood was boiled, through the fire of Sun the Soul was carried, by God's breath the life came, into the Hearth the first hearthling was brought.
The first hearthling, most powerful that ever was and will be, was assigned by the Old Gods as the first lumberjack, who will chop down the World Tree, when the time comes. For the Gods knew, if they themselves won't decide to end the Hearth, the Time will do it for them.
The rest of the Hearth kin were spread across the land, to survive, then to develop, then to mold the world. Due to their connection with the Sun, early hearthlings were able to sustain their bodies on sunlight solely. They were until the Old Gods decided to cover such antiquity.
Chapter VII: The nature of Hearth kin
Each hearthling has a soul and each soul has a fate. To watch over hearthlings fates, three Norns were created. Over the River of Time, they weave the fabric of fate and only they know, where each and every thread ends.
For each hearthling to be born, their soul must travel from Dream to Hearth by burning in the everlasting fire that is a reflection of the sun in the world of un-real. When each hearthling is born, a hearthfire appears that is a reflection of an everlasting fire their soul passed through.
When each hearthling dies, their soul returns to the Dream. With ritual their predecessor may connect with this soul and, by uncovering the veil of real with the help of ancestor, manipulate the fateweave.
Unlike animals and woodland spirits, hearthlings are not born connected to the Hearth, instead they grow their bonds as they explore and exploit the world's wonders. Each drop of experience makes hearthling more powerful and more connected at the same time.
Through learning the names of things, through growing familiar with the very core of the Hearth, a few hearthlings can see the fate of it, in the most frightening visions. In their nightmares they see how the world will end.
Chapter VIII: The end of Hearth
When the Old Gods wear tired of this world, the Moon will stop it's eternal chase and the cruel sun will shine constantly as aeons before.
Blinded by the powerful light, the dragons will screech and rattle their chains, awakening the trolls of the Hearth.
The First Lumberjack will cut the World Tree and the ground will tremble upon it's fall, opening chasms into the Hearth molten core.
Hearth law will lose it's weight, all bonds of blood and soil will be crushed, all walls will crumble and hearthling will go against hearthling.
The ocean will boil, the mountains will crack, the chains will be broken and the world will end...
Only to be reborn again...