The Great Kingdom originated from the Moon - Theory
So just a theory I made when combing through One Piece for the answers to the mystery of the Void Century, is how out of place the Great Kingdom seems.
The great Kingdom's tech level was millennia ahead of what the world had before Vegapunk came around to modernize the world, and is treated as extraordinary by the people of modern day. but you know what? What is more interesting isnt that there used to be this hyperadvanced nation in the past... but how it does not at all fit with what sort of world it existed alongside in that distant past.
The two nations that were allied with the great kingdom, Wano and Fishman Island, have ancient, ancient architecture stretching back to what was probably the period of the Void Century, if not even before, and they fought alongside Joy Boy.
and both took great pains to prepare in the aftermath of Joy Boy's great defeat... But one thing to note, is that though their great works, Noah and Wano's walls, are extremely impressive, neither seems to have been the result of some amazing technology. Noah is just a stupidly large ship, while Wano's walls were no doubt made with some sort of devil fruit.
Why is this important? Because neither side exited the void century with great technology(not counting Pluton obviously).
similarily, Water Seven where Pluton was made, though very impressive and advanced in it's own way, is not on the level of what we know of the great Kingdom.
The time period of Monsters were not hyper advanced either, looking like a wild west town, but seemingly not having guns, not even flitlock ones.
The point im building towards, is that the Great Kingdom cannot have been around for a very long time historically speaking, because even though the world was far, far more interconnected than it is now, NONE of their technology had spread around by the time it fell, not even to their allies.
This suggests that the Great Kingdom was either very, very isolated before the great war kicked off, or they pretty much just showed up out of nowhere into a world that was a bit further than the medieval period, but not by that much.
But where would they come from? An isolated island?
Actually no, because there is one people who was hyper advanced, big into robotics, had similar architecture to the great kingdom, joy boy dressed in their fashion, and they made a massive emmigration from their home that was completely separated from the One Piece Earth in search of resources to power their technology.
Im of course talking about the ancestors of the various Skypians, who left the moon over a thousand years ago.
A people with extremely advanced technology, who's architecture is found all across the one piece world, Be it enies Lobby, Baltigo, and yes, even the great Kindom itself.
All important buildings that were ruined in some great conflicts, and though the exact architecture differs a bit, there is a clear similarity.
of course the great kingdom sunken beneath the waves is a bit different, as you can clearly see that it's a mixture between the kind of old style we saw in the Oharan flashback, mixed together with the style of the fishman Palace of their allies. but there is one part that is easy to miss unless you're looking for it, righ up in the upper left corner.
Yep, that's it right there, the triangle pattern symbol the moon people were so fond of. it's a bit different across all of them, but that is a pattern that runs through each of these, even ignoring how similar the building styles is between each.
then of course there is joy boy himself, who in addition to his devil fruit, fought with a spear and sword, and went naked save for a loincloth of some kind. Extremely similar to the ancient shadians, just withouth pants and wings on his back.
And though we dont know that the shandians fought on the side of the ancient kingdom, we do know that they DID fight the 20 kingdoms during the void century to prevent them from totally destroying their home.
That suggests, but does not confirm that they fought for Joy Boy, like wano and the Fishmen.
And though they dont worship him by name, The shandians, just like the Giants of Elbaf, venerate Joy Boy as a god, calling him the Sun God(this being the first time he was ever mentioned actually), further hammering the point of there being a massive connection.
So with all of this in mind, there is the question of how does all of this fit together?
So the people from the moon came to the earth with hyper advanced technology in search of resources. How does that lead to the great war, and the end of the then world?
Well there is a timeline.
When the people from the moon came to the Earth, they split into 3 distinct groups. one of them were the Shandians, the others were the skypians, and the third was Eneru's people, who now is de facto extinct.
Shandora was founded by the people known as the Shandians 1100 years ago, several centuries before the great war and the void century.
So there was a period before everything came to a head, before the massive conflict erupted and the 20 kingdoms banded together because they saw the great kingdom as such a threat that either they put aside their differences and came together as one, or they would be crushed by Joy Boy and his nation.
The people of the moon left their home behind because they ran out of resources to keep it going.
Now, there is a VERY strong similarity between the powersources of the ancient moon city of Birka, and the Mother Flame, but im not going to go too much into that right now.
What is FAR more important to understand the situation of the early great Kingdom is how when they came to the world, they needed resources, and were STUPIDLY more advanced than all their neighboors.
That combination historically, only leads to one thing. Conquest.
That might not have been how it started, but the manga has hammered in time and again, that though the world government in the present is evil beyond any redemption, the orignal conflict was probably a lot more grey or nuanced than the modern ruling state might lead one to believe. Rayleigh tells robin that her people were too hasty in their judgement of history, and despite having all the motive and justification in the world to throw Imu and the world nobles under the buss, Vegapunk refuses to come right out and say the world governments motives are pure evil.
If the original conflict was 20 nations of various moral character banding together to fight one that had entered into an era of expansion hellbent on their subjugation, that would make a lot of sense.
The gold plated city of shandora, coated with gold that was probably taken in conquest or as tribute.
this is further backed up by the fact that of the 3 great weapons that leveled the world, Joy Boy controlled 2 of them, while the Allied powers only had Uranus.
Joy Boy's ally/lover/comerade Posidon didn't just fight for his side, due to the nature of her powers, she would have had to direct the sea kings personally in order to unleash them upon the coastlines of the 20 kingdoms.
And of course there is Pluton, a ship said to be able to sink an island with a single blast, which at the end of the war was still on Joy Boy's side.
The world of old didnt end because the Allied Powers unleashed Uranus on their enemies, it ended because both sides hated the other so much, that they regarded any and all sacrifices as justified in order to win the war.
So with this in mind, we have a clear picture of how things unfolded. The people of the moon came to a primitive world, settled down to try to rebuild, made friends with several nations like Wano and the Fishmen, but also began to make enemies, as the centuries went on.
a couple of centuries later, things had gotten really, really bad, and a war to end all wars began, for the fate of the world. Joy Boy lead his people into the war, commanding poseidon to obliterate coastline after coastline and used Pluton to rain down death on any city or fortress, of their enemies. The allied powers somehow managed to capture Uranus and rained down death from the sky upon Joy Boy's kingdom on places such as Enies Lobby.
A century of war followed, and the Grand Lines continents was sunk beneath the sea, but the actual war only ended with the final defeat nad likely death of Joy Boy.
He was the great center of his side, the torch that kept the side going through decades and decades of death, slaughter and total destruction, and with his death, the will to keep the thing going ended.
Poseidon retreated back to Fishman Isle, while the powers that be from Wano retreated back to their home with Pluton, and began to fortify their home for the innevitable backlash that didnt end up coming.
The Shandorians, who may, or may not have been the main ethnicity of the kingdom(and if not certainly shared kinship with them as fellow people from the moon), was shattered as a great power despite having been known for a period as one of the grand Lines greatest civlizations(the fact that this historical fact hasnt been erased completely from history, is what makes me believe that the Shandorians werent the main sky people that founded the great Kingdom, just their allies and kinsmen).
