This year has been a pretty good one for the One Piece franchise. The anime has been doing great, a new movie has premiered, Luffy's Gear 5 was finally unveiled and the final saga of the series has officially begun. As exciting as all this is, it's still rather peculiar how many mysteries remain unsolved.
By the end of Wano, many tidbits of information had been revealed. Luffy's Devil Fruit powers never came from the Paramecia-type Gomu Gomu no Mi but rather the Mythical Zoan fruit, Hito Hito no Mi, Model: Nika. Even crazier, those powers of the Sun God were also used by the legendary figure of the Void Century, Joy Boy, and Luffy is supposedly meant to be the "second coming" of him. Unfortunately, very little information beyond this has been officially revealed, though a new theory has appeared that not only fills in a lot of the blanks still present but even manages to connect and explain another longstanding mystery, "The Will of D."
Who Was Joy Boy?
While not much is known about him, Joy Boy is seemingly one of the most important characters in the story of One Piece. The first time he was mentioned was during the "Fish-Man Island" arc, after Nico Robin read a message inscribed on a Poneglyph. The message detailed a promise between himself and the resident of Fish-Men Island -- one that he was apparently forced to break. He was supposed to help bring the residents to the surface through the use of the Ancient Weapon Poseidon and the ark, Noah, but wasn't able to keep it for an unknown reason. The Poneglyph states an apology to the Fish-Men and promises that someone in the future will come to fulfill the promise he made to them.
There was also another message on a different, unnamed island that prophesied that Joy Boy's return would happen 800 years after the Void Century -- coincidentally, around the same time that Luffy started his journey. This was further confirmed during the Oden flashback, as Gol D. Roger stated that he and his crew arrived at Laugh Tale too early after reading a message left there by the first Joy Boy. However, it seems that the time has come, as according to Zunesha, the giant elephant that holds the nation of Zou on its back, Joy Boy officially returned when Luffy awakened his Devil Fruit, unlocking Gear 5.
What is the "Will of D"?
The D Clan is a mysterious group of people that exist within the world of One Piece. What signifies them is the rare "D" initial in their names, setting them apart from the majority of people in One Piece. Only a relative handful of them have been revealed so far, but they each seem to share a few traits, making them even more peculiar. As stated during the "Dressrosa" arc, those with the initial carry something known as the "Will of D." For some reason or another, this makes them direct enemies of the gods -- in this case, the Celestial Dragons. Based on remarks made by the World Government and the Navy, those that carry the "D" initial frequently cause problems for them and become their enemies. Interestingly enough, this has been the case with almost every "D Clan" member so far.
Luffy declared war on the World Government during Enies Lobby, as did Marshal D. Teach during Marineford. Rocks D. Xebec tried to take over the world and overthrow the World Government by directly attacking the Celestial Dragons. Monkey D. Dragon, Luffy's father, is also considered to be the "world's worst criminal" and is the leader of the Revolutionary Army. The most famous member with this initial was probably Gol D. Roger, the man who would conquer the Grand Line and become the King of Pirates.
Even when they work for the Marines, those with the "D" initial become problematic. Navy Vice Admiral Monkey D. Garp has no love for the Celestial Dragons and frequently and openly berates them, even refusing promotions to the rank of Admiral because he'd have to work directly under them. Jaguar D. Saul is another great example, who defected from the Marines after he learned that they planned to perform a Buster Call on the island of Ohara. He went out of his way to protect the island but died in the process. Coincidentally, Saul and all the other "D Clan" members have died with smiles on their faces, as could be seen with both Roger and his wife and son, Portgas D. Rouge and Portgas D. Ace.
How the Theory Connects the Two
This new theory states that the Will of D and Joy Boy are directly connected, which would actually make a lot of sense. Considering that Joy Boy was directly opposed to the World Government, the "D Clan" would be opposed to them too since it is run by the Celestial Dragons. The theory states that the "D" initial is an abbreviation for the Dawn Pirates, a crew supposedly led by Joy Boy. While there has never been any confirmation of a group known as the Dawn Pirates, it wouldn't be impossible for them to have existed during the Void Century. Those that carry the "D" in their names are theorized to be direct descendants of Joy Boy and his crew, which would explain what the "Will of D" is meant to stand for. As their ancestors fought a war against the current World Government, the current members of the "D Clan" could have inherited the will to stand against them, even centuries later.
Interestingly enough, the theory also brings up Jaguar D. Saul specifically, further tying it all together. It states that Joy Boy's true name was Jaguar Binks and that he was a giant from Elbaf. While the theory uses the fact that the names Joy Boy and Jaguar Binks have the initials as part of its reasoning, that is only the tip of the iceberg. The theory posits that the giant straw hat at Mariejois used to belong to Joy Boy, which would explain its significance as well as statements made by characters about Luffy and his own straw hat. The final bit of proof it gives -- specifically, why his name would be "Jaguar Binks" -- is that the song Binks' Sake is directly about Joy Boy.
The giant straw hat is very peculiar, so it would make sense that it is kept as a sort of trophy or reminder of the World Government defeating Joy Boy, though at the very least, it implies that it was something that had to be worn by a giant. The only giant with the "D" initial so far has been Saul, which could hold much greater significance than the story has previously let on. It also makes sense that Elbaf would have some ties to the Ancient Kingdom and Joy Boy since they don't seem to be affiliated with the World Government, much like Wano isn't. Along with the significance of the Binks' Sake song for pirates, it also wouldn't be hard to believe that Jaguar Binks really was the name of Joy Boy.
Obviously, as this is just a fan theory, all of this should be taken with a grain of salt. That being said, it does offer some satisfying explanations for a lot of mysteries currently left unsolved. The "Will of D" being directly related to Joy Boy and his hypothetical pirate crew would also answer some questions quite well. While this aspect of the theory relies heavily on the idea that this crew would be named the Dawn Pirates, it's not impossible for the crew to have been named that or something else starting with "D." Even if that doesn't turn out to be true, the series has still heavily implied that Joy Boy was a giant, giving at least some credence to this theory. Time will tell whether some or any of this is accurate, but with One Piece in its final saga, answers will be coming soon enough.