I wanna first start this theory off by stating a few things; I don't have access to some of these scans due to the ages of them so I will be directly referencing specific chapters and/or pages. This theory also covers a lot of topics so bare with me, there will be a table of contents to help sort through it all. I'm not entirely done typing up every thing for the theory either so it will grow over time. Now, without further adieu, I present: THE VOID CENTURY "The Void Century is a century-long gap in recorded and archaeological history, the study of which is forbidden by the World Government. These events occurred 900 to 800 years before the current story line." TABLE OF CONTENTS GREAT KINGDOM ANCIENT KINGDOMS THREE ANCIENT WEAPONS PONEGLYPHS WILL OF D MISCELLANEOUS GREAT KINGDOM So let's start everything off with probably the most important part of the Void Century, the Great Kingdom, or how I see them, the actual protagonists from One Piece those 800+ years ago. I believe the Great Kingdom was actually the "good" guys in the conflict of the Great War and the Twenty Kingdoms now known as the World Government banded together to overthrow them to unseat them as the strongest nation in the world. While the strength of the Great Kingdom has been stated numerous times, the Great Kingdom has never been mentioned in the light of tyrants or oppressors, in fact it was referred to as prosperous. I believe the strength and size (important) of the kingdom intimidated and upset the other kingdoms at the time. Knowing that none of them could defeat the kingdom on it's own, they formed an alliance to overthrow the world's strongest superpower. I believe this was done in part through betrayal, which leads into the next section. References One Piece Yellow: Grand Elements (p. 276) - Naming of the kingdom One Piece Manga (c. 395) - Professor Clover beings to go into detail about the Great Kingdom and why the researching of the Void Century is forbidden ANCIENT KINGDOMS While we know that at least twenty-three kingdoms existed at the time of the Void Century, I think the connections of those kingdoms were vastly different at the time. I also think that after the Great Kingdom there were certain kingdoms that were either allied with the Great Kingdom or held incredible influence in their own right, such as Wano Country. WANO COUNTRY - While Wano Country is not currently affiliated with the World Government, we know that Wano Country is tied to four major points that lead back to the Great Kingdom: The Kozuki family, the creators of the Poneglyphs Zunisha, the walking elephant that predates the Void Century who was stated to be walking for eternity due to being punished for a crime it committed long ago (also suggested it's actually walking towards something specific) Zou, the home of the Mink Tribe, of whom Inuarashi and Nekomamushi were retainers for Oden Kozuki (whom visited Raftel) and the location of one of the four Road Poneglyphs The single Gorosei member that is dressed in samurai garb similar to that of the Wano people I believe that the Wano Country were either allies of the Great Kingdom who didn't participate in the Great War or betrayed the Great Kingdom during the Great War. FISHMAN ISLAND - I believe that Fishman Island was an ally of the Great Kingdom as well for a few reasons: Joy Boy, not only was he capable of inscribing an apology on a Poneglyph (which means he not only knew the method to leave messages on them but also knew the language specific to the Great Kingdom) but also made a promise to raise Noah (which is stated on numerous occasions to have a specific purpose and is intended to be pulled by Sea Kings, Poseidon's power) to the surface. Fishman Island exists right under Mary Geoise, which I believe to be one of the last remaining structures of the Great Kingdom, which is why the 19 Kingdoms claimed it as their own holy land, "geoise" also means jealously in French. ALABASTA - We also have Alabasta, which as we know were a part of the Twenty Kingdoms that fought the Great Kingdom. I feel like Alabasta was originally an ally to the Great Kingdom but betrayed them during the Great War. While I don't have as much to support this theory as Wano and Fishman, we have to acknowledge a few things: Alabasta was the only kingdom that chose not to move to Mary Geoise after the defeat of the Great Kingdom, which could suggest that something made the king feel like that wasn't the right choice, which could be because they betrayed them or something else entirely Alabasta also houses a Poneglyph that reveals information on Pluton, one of the ancient weapons. It was also stated that Alubarna existed prior to Alabasta, whose palace is very similar in design to Mary Geoise and the shogun's palace in Wano and (arguably) Ryugu Palace Pluton was specifically delivered to Alabasta for some undisclosed reason, possibly due to them being allied with the Great Kingdom OHARA - I feel there is also a need to mention Ohara and the Tree of Knowledge, being the only known structure to predate the Palace of Alubarna and was home to the Oharans, the only people capable of deciphering the Poneglyphs outside the Kozuki and beings who could hear the Voice of All Things. The Tree of Knowledge was a library that was home to texts and history that also predated the Void Century itself, which undoubtedly held information about the Great Kingdom and its rise to power among other ancient knowledge Professor Clover and the archaeologists capable of reading the Poneglyphs all hailed from Ohara, potentially due to the fact the Tree of Knowledge housed information on how to read the Poneglyphs themselves SHANDORA - We also have to speak on Shandora, which I believe was another ally of the Great Kingdom. They along with the Great Kingdom were attacked by the Twenty Kingdoms and were defeated. We know that old depictions show the Shandians, Skypieans and Birkans leaving together on the moon before they journeyed to the Earth and that they built the Automata race. Dr. Tsukimi actually built Automata on Karakuri Island similar to the Automata from Fairy Vearth, which was revealed to be a technological marvel. He also often watched and studied the moon an actually died when he saw an explosion that occurred on the moon. You know who else grew up on Karakuri Island? Dr. Vegapunk. I believe that Karakuri Island existed before the Void Century and was visited to some degree by either the Skypieans or Birkans. The technology discovered/created there is a result of either the guidance of one of those tribes or the study of the technology they brought with them or somehow ended up on Karakuri Island. All these could also lend themselves to why Shandora was attacked alongside the Great Kingdom if they were in fact allies, which I also believe they were because of Uranus, the last ancient weapon. Before being sent up by the Knock-Up Stream two Poneglyphs also existed on the original kingdom of Shandora, one an instructional Poneglyph and the other the Poneglyph for Poseidon. References One Piece Manga (c. 818) - Nekomamushi reveals the Kozuki made the Poneglyphs One Piece Manga (c. 821) - Nekomamushi reveals that Zou's punishment was to walk the seas for eternity One Piece Manga (c. 802) - Law states that Zou (and Zunisha) have existed for 1,000 years, predating the Void Century One Piece Manga (c. 822) - Miyagi mentions that the Mink Tribe will one day have to leave Zou and that he believes Zunisha is walking towards something One Piece Manga (c. 818) - Kinemon reveals that Oden sailed with Gol D. Roger and reached Raftel One Piece Manga (c. 233) - Gorosei revealed One Piece Manga (c. 628) - Robin reads about Joy Boy on the Ryugu Poneglyph One Piece Manga (c. 649) - Neptune explains to Robin who Joy Boy was One Piece Manga (c. 621) - Part of Noah's purpose is explained One Piece Manga (c. 636) - Neptune stats Noah isn't supposed to return to the surface until a specific day One Piece Manga (c. 722) Doflamingo explains to Law how the 19 families came to live in Mary Geoise One Piece Yellow: Grand Elements - describes the Tree of Knowledge One Piece Manga (c. 261) - Robin reads the history of Shandora One Piece Manga (c. 272) - Robin speaks on the fate of Shandora One Piece Manga (c. 465 - 474) - Enel learns the true history of the Sky People, discover and reactivate the Automata, and finds the ruins of Birka One Piece Manga (c. 448) - Karakuri Island is first shown as Tsukimi creates Automata One Piece Manga (c. 549) - Franky finds Vegapunk's old home on Karakuri Island THREE ANCIENT WEAPONS So as we all know, the Three Ancient Weapons follow a specific theme, Pluton represents Earth, Poseidon represents Sea and Uranus represents Sky. We also know that each weapon, while representing a different aspect, are all closely related to the sea, Pluton being a warship and Poseidon being a mermaid, and we also know that Pluton was an object while Poseidon was a living person, which leads me to believe that Uranus might actually turn out to be an incredibly rare devil fruit. Not only are devil fruits tied directly to the sea but the fruits represent the middle ground between an inanimate object and a living entity. PLUTON - Pluton's Poneglyph was discovered on Alabasta, the only Kingdom of the Twenty Kingdoms that chose not to move to Mary Geoise and a very dry place overall. We also know that Pluton was built on Water 7 and was delivered to Alabasta some time ago, possibly with the Pluton Poneglyph as well. Why would Pluton be sent there unless Alabasta and the Great Kingdom were allies at some point? POSEIDON - Poseidon, currently Shirahoshi who has the ability to control the Sea Kings and exists on Fishman Island, right beneath Mary Geoise, the holy land of the World Government and (to my beliefs) part of the original Great Kingdom. We know that Sea Kings are among the top predators in the entire One Piece world and that it takes a great deal of strength to defeat them. Sea Kings could very well be the living embodiment of the sea, which makes sense as to why Seastone, the physical representation of the sea, affects them. Sea Kings are naturally attuned to the sea and pick up on anything that doesn't share its same wavelength, which is why Seastone makes things from them. URANUS - And last we have Uranus, which, while we have no information on, we can definitely speculate towards its relationship to the sky, and more specifically, the original Sky People and the moon. We know that Shandora and the Great Kingdom both existed during the shame time, which means that the three tribes of the Sky People had already made their journey to the Earth, though the Shandian tribe was the only one confirmed to actually reach the blue sea. We also know that the Sky People were an technologically advanced race and that the Great Kingdom was a powerful and prosperous kingdom, it stands to reason that they were possible allies and could have worked together to advance their civilizations and possibly create the Three Ancient Weapons together. Of course during this time they weren't actually weapons but valuable treasures that represented every aspect of the world. I will add more to this section as I finish up more research. One Piece Manga (c. 352) - Pluton is revealed to be a warship One Piece Manga (c. 649) - Neptune and Robin discuss Shirahoshi and Poseidon One Piece Manga (c. 650) - Neptune and Robin discuss the Three Ancient Weapons PONEGLYPHS COMING SOON! WILL OF D I believe the Will of D to be one of the more interesting aspects of the Void Century and that it directly ties to it which is why the World Government is so concerned with those who possess it. I believe those who have the Will of D are direct descendants of the original people from the Great Kingdom. There have been numerous instances of the Will of D being mentioned not simply as some strange phenomena but a sort of lineage, such as when Saul spoke on his entire family having it, or the fact Luffy's father Dragon and grandfather Garp also possess it. Law's family also had knowledge of it and actively hid Law's attachment to it, suggesting that other's in his family either possessed it or had knowledge of it. The same goes for Roger, Rogue and Ace. The Will of D has also been mentioned in conjunction with the Void Century and One Piece in conversation by multiple characters, such as when Ussop and Robin questioned Silver Rayleighs about the Will of D, the Void Century and One Piece. Whitebeard also mentioned the Will of D and One Piece together suggesting that they are not solely tied together by Gol D. Roger. Rosinate also mentioned the fact that those who bear the Will of D are considered to be the enemies of God, who we have come to known as the Celestial Dragons, the descendants of the kingdoms who originally fought against the Great Kingdom. Carriers of the Will of D have often been referred to as figures capable of creating major changes in the world: Gol D. Roger started the Golden Age of Pirates Jaguar D. Saul saved the last remaining person who Earth currently capable of reading the Poneglyphs (Pudding doesn't know how to read them yet) in Nico Robin Monkey D. Dragon, the leader of the Revolutionary Army and considered the most wanted man in the world Monkey D. Garp, known as the Hero of the Marines, who fought equally with Gol D. Roger and has some historical tie to the Rocks Group, the strongest collection of people before Gol D. Roger's rise to prominence Portgas D. Rogue being able to extend her pregnancy for 5 extra months to protect Ace from the marines Portgas D. Ace who was a commander in Whitebeard's army and traveled to numerous islands across the seas and even fought equally with Blackbeard Trafaglar D. Water Law not only being the only survivor of Flevence but becoming a supernova and fighting on par with Doflamingo Monkey D. Luffy, the fifth emperor of the sea and current head of the Straw Hat Fleet. Marshall D. Teach, the only person in known history to possess two devil fruits and current Schibukai These accomplishments from the members of the Family of D coincide with the statements of the Great Kingdom's power and influence during its peak. References One Piece Manga (c. 392) - Saul talks about the initial D One Piece Manga (c. 591) - Law wonders about the secret behind the Will of D One Piece Manga (c. 729) - Law mentions the Will of D One Piece Manga (c. 763 - 764) - Rosinate reveals the secret of D and the Family of D to Law One Piece Manga (c. 576) - Whitebeard reminisces about a conversation he had with Gol D. Roger concerning the Will of D MISCELLANEOUS COMING SOON!