Void Century is easily one of the biggest mysteries in One Piece because, as the name suggests, it is a period of about 100 years where there is absolutely no historical data left. It is basically a blank page in the history books. This is also the topic that the people of Ohara tried to uncover before the World Government launched the Buster Call that destroyed their research, their homes, and their population.

As the only surviving member of the Ohara, Nico Robin is now the only one who continues their research to find out what actually happened during the Void Century. From what we’ve seen in the story so far, the Void Century seems to have an integral role in the overall saga of One Piece. So it’s highly likely that we’ll get the full explanation about it in this last arc.

The Poneglyphs are giant, cubic steles that are scattered all over the world, with ancient language text written on their surfaces. The content varies from one Poneglyph to the next, but for the most part, they share bits of information about the Void Century. Among all of these Poneglyphs, there are 4 special ones called the Road Poneglyphs. The legend says that the information written in these 4 Poneglyphs will reveal the location of an island called Laugh Tale.

We know through the Wano Arc that these Poneglyphs were made by the craftsmen from Wano Country. We can also assume that the people who made these Poneglyphs wished to pass certain information on to the next generation. But if that’s the case, why did they have to use something as durable and hard to handle like the Poneglyphs? Why didn’t they simply pass the history through regular text like those who came before and after them? Did something happen that forced them to take such a drastic measure as writing history on the most durable object known in the world?

The story of the founding of the World Government is quite epic. The legend says that the world used to be drowned in chaos. But then, the kings and queens from the 20 biggest kingdoms joined hands together and formed the World Government: a governing body with the sole purpose of bringing peace and order to the world.

To ensure a proper democracy, there’s no leader among these 20 kingdoms. All share the same rights and responsibilities, and every decision has to be discussed first, which is the reason why the Reverie exists. The symbol of that decision is the empty throne in the heart of the Holy Land of Mary Geoise.

That all sounds grand and inspiring, however, that is certainly not the truth. Because while it is true that the leaders of the biggest kingdoms in the world do indeed gather at the Holy Land o fMary Geoise for the Reverie, we know that the 5 elders are the ones that are pretty much in charge of running the government.

Not only that, but we also now know that there is a mysterious figure called “Im” that the elders bow their heads to. Furthermore, Im is also the person who sits comfortably on the empty throne. There is basically a shadow government within the World Government. If that is the case, maybe there’s more to the history of the foundation of the World Government that we don’t know about? Hopefully, we’ll find the truth about it in this arc.

During the all out battle with Kaido’s forces at the end of the Wano Arc, a member of Kaido’s Tobiroppo called Who’s-Who reveals a massive secret to Jinbe. Apparently, he used to be a member of the CP9, a secret intelligence agency of the World Government. And over a decade ago, he failed in one of the most important missions given to him by the 5 elders, which was to guard the devil fruit Gomu Gomu no Mi during its journey to a safe place.

We know that the one who stole that devil fruit was none other than the Red Haired Shanks. As it happened, that is also the fruit that Luffy ate when he met Shanks when he was small, which gave him his iconic rubber power.

Through Luffy’s last fight with Kaidou, we know that the awakened version of Gomu Gomu no Mi is actually a lot stronger than we ever thought before. But that raised a question: why did the government try to hide the fruit? Sure, it is unexpectedly strong, but so is Whitebeard’s Gura Gura no Mi. And in terms of danger, Blackbeard’s Yami Yami no Mi that has the power to steal other devil fruits’ powers is certainly much more dangerous, right? So why did they feel so concerned and threatened by Gomu Gomu no Mi?

Based on the information written on the Poneglyphs, Nico Robin found that there are three ancient weapons in this world. They are called Pluton, Poseidon, and Uranus. Each of these weapons are capable of causing mass destruction.

Pluton is known to be a powerful warship that is capable of destroying anything. It was first brought up during the Enies Lobby incident. At the time, Franky destroyed the blueprint for Pluton, so there’s no way to build one from scratch. However, we now know that the original Pluton actually still exists right at the bottom of the Wano Country.

Poseidon is actually the mermaid princess Shirahoshi. She is the prophesized mermaid that has the ability to not only communicate with the colossal sea kings, but also has the right to command them. The last mermaid from the royal family that had that ability is said to have been born 800 years earlier, during the time of the Void Century. As for Uranus, well, there’s no information available about it right now.

We can assume that these ancient weapons were used to cause mass destruction during the Void Century. Mermaid princess aside, why did people at the time feel the need to create such dangerous weapons? What kinds of enemies did they face that required such massive firepower? Or were they actually using the weapons to fight against each other?

Throughout the series, people with the initial “D.” have been popping up one after the other. Gol D. Roger, Monkey D. Luffy, Marshall D. Teach, and even Trafalgar Law is said to actually have a D. in his name, just to name a few. It turns out that it is not a coincidence. There is something called the “Will of D”. In fact, it is said that the bearer of the name “D.” has the capacity to wreak havoc and change the world, be it for the better or worse.

We don’t know where these initials came from. Was there a clan that bore the name D. in the past? Did the people who had this initial in their name unconsciously chase after the same objective or share the same purpose? What is the “Will of D.”, anyway? Hopefully, all will be revealed in this final arc.

Joy Boy is a name that we first heard about through the Poneglyphs in the Ryugu Kingdom. From that point on, we hear his name repeatedly mentioned in the story. From the information that we’ve got so far, Joy Boy is actually an incredibly influential person that lived back during the Void Century. His actions caused a massive change in the world back then, although we don’t really know what kind of change it was.

We also know that he was the previous user of the Gomu Gomu no Mi, and it was prophesied that his successor would be born 800 years in the future, when the world needs him the most. Since Luffy is the current user of the Gomu Gomu no Mi, it is implied that Luffy is the current Joy Boy. That being said, there are tons of things that we still don’t know about the original Joy Boy, so hopefully we’ll find out more about him in this arc.

As mentioned above, we first get to know about Joy Boy through the Poneglyphs in the Ryugu Kingdom. There is actually something special about that particular Poneglyph. Unlike the other ones that we have seen before, the text written on it is actually an apology letter from Joy Boy to the fish-man island because he could not fulfill his promise to them.

The content of the promise itself is still unknown at this point. However, we know that it involved the colossal ship called Noah that is hidden in the Forest of the Sea, the mermaid princess at the time, and the sea kings under her command. The letter also said that in 800 years’ time, somebody will come along to fulfill Joy Boy’s promise in his stead. Since Luffy is assumed to be the current incarnation of Joy Boy, it’s safe to say that we’ll know more about this mysterious promise soon.

At the foot of Mount Fuji, underneath the Wano Country, lies the ancient weapon Pluton. The only thing that prevents this ancient warship from getting out of Wano is the massive rocky mountain range that acts as a natural barrier for the country. So when Oden talked about opening up Wano’s border, he meant to destroy these mountains.

However, that would also mean unleashing Pluton into the world. It’s impossible for Oden to not know about Pluton, because it is a secret that has been passed down for generations within the Kozuki Royal Family. The only explanation behind Oden’s intention must’ve been that he received another piece of information during his travels with Gol D. Roger that compels him to open up Wano’s border.

This seems to be the most plausible explanation, because in his final moments, Oden asked his retainers to open up the border in order to welcome the arrival of Joy Boy, who is promised to arrive 800 years after the Void Century, which is about 20 years after Oden’s death. As to that piece of information that Oden found during his journey, well, it is still a mystery that we hope will be revealed in this arc.

Silvers Rayleigh, the Pirate King’s second in command, has confirmed that the One Piece indeed exists and is waiting for whoever can reach the final island of Laugh Tale. We also know that One Piece is actually a treasure left by Joy Boy 800 years ago.

Till this day, Gol D. Roger and his crew are the only ones that have found the One Piece. However, a strange story has begun to circulate among those who wish to find it. Apparently, when Gol D. Roger found the One Piece, he and his crew immediately burst out laughing, which is why he named the island “Laugh Tale”.

According to legend, other than the One Piece, there are also mountains of treasure unlike anything that the world has ever seen, and there also lies the truth about the history of the world. So what did they find on that island that could cause them to laugh like that? Well, it seems that we’ll find out about it when Luffy and his crew finally arrive at Laugh Tale at the end of this final arc.