Earth was so fiery it was like a sun, mankind came from the moon and the deity of earth is either earth's original population or the elements.
OR
the forbidden sun is nuclear energy (the possible source of energy required to create the devil fruits?).
There must have already been a quite advanced civilisation considering enslaved people already exist.
They willed the Sun God fruit into existence, either by harnessing the aforementioned possible energy source with their minds or 'praying' is a figure of speech and they used science to harness the energy source (forbidden sun).
The nuclear 'sun' ( unintentionally) acted like a bomb causing global destruction. The fiery serpent might be magma shooting out of the ground following a disturbance of plate tectonics and potentially creating the Red Line.
And the overwhelming forces of nature destroyed everything.
''In emptiness, there is breath'' sounds like a quote from the old testament, signifying the return of life to earth exemplified by the existence of forests.
The second era's sun has to be Joyboy but this text makes him seem like a bad guy. People of the moon are the descendants of the moon people like the winged folk including Lunarians and / or the creatures that still currently live on the moon. People of the half moon are the Shimotsukis and their allies.
The 20 human kings of earth slayed Joyboy and crowned themselves gods of the world, creating the World Government.
The rampaging deity of the sea signifies the rise of the sea level.
Now, as to what the 'demons' are that the forest God spreads, perhaps the devil fruits. This would mean that the Sun God fruit was the first and, for a very long time, the only devil fruit.
First line speaks of the Void Century. The troubled shadow is Imu? Is the 'sound' mentioned here the Drums of Liberation? What is the 'fragmented moon'? The actual moon is not in fragments so it could be referring to the totality of the descendants of Joyboy's allies, reflecting their scattered current state.[/QUOTE]
I wrote this right after the spoilers dropped but now that I think about it, the moon people are only mentioned in part 2 so it's possible that nobody came from the moon originally and they only escapes after the first t destruction.
And idk where Blackbeard or the previous owner of the fruit /original God of darkness is in this story.
The three introduction lines On earth, there is flame.In emptiness, there is breath.In chaos, there is void. might describe the order in which the Gods came to be and the significance of their contemporary devil fruit users:
earth = imu
Flame = Sabo
Emptiness = Blackbeard
Breath/wind = dragon
But this part is very speculative.
Blackbeard might as well be chaos or void(more likely just stands for the good century).