Disclaimer: Everything on this page has a lot to do with the absolute latest revelations so please do not read this unless you are caught up entirely with the manga as of Chapter 649. Thank you!

This will be a long read but hopefully an enjoyable and interesting one. For those of you who are faint of heart, if you want a TTTTLLLL;DR version, scroll down to the very bottom. Otherwise, lets begin with…

Gol D. Roger and Monkey D. Luffy. If we want to understand this theory, we have to start with the two Pirate Kings. They have a lot in common to be sure, but I think the single most important revelation about them is that aside from Shirahoshi, they alone have the ability to communicate with Sea Kings, the true power behind Poseidon.
Unanswered Questions: Why only Luffy and Roger?

Whitebeard. Roger told Whitebeard the meaning of the D. Since then, it seems like Whitebeard has been actively protecting the D.’s: he was literally grooming Ace to be the next Pirate King and even went so far as to order Marco to ensure Luffy lived through the war. Moreover Whitebeard reveals that Roger has been waiting for someone, an implied carrier of the Will of D., to find One Piece, sack up and “challenge this world.” More interestingly, Whitebeard alludes to this sort of task as something Teach no longer is qualified to do.

But why not Whitebeard? Ace was about to get executed – would Whitebeard really not do everything in his power to save Roger’s son? I don’t think we have any reason to believe Whitebeard couldn’t get One Piece if he so chose. One explanation then is that perhaps he very literally could not get/do anything with One Piece because there is some sort of restriction on it. Further collaborating this notion is the fact that Whitebeard says One Piece has nothing to do with him, although he could have just been talking about him wanting nothing to do with treasure at all.
Unanswered Questions: Could Whitebeard simply not obtain/use One Piece at all under any circumstance?

Will of D. We’re definitely reaching now, but isn’t that the fun of it? It may just be the case then, that in order to reach/do anything with/about One Piece, you must carry the Will of D. That maybe those people who find One Piece who also carry the will can do something that nobody else can do. If we assume that Luffy will find One Piece and do whatever it is that Roger was unable/unwilling to, we have to examine the differences between them.

Because Whatever One Piece Can Do, Roger Didn’t Do It. Roger carried the Will of D., could hear Sea Kings, found One Piece, learned the history of the Void Century, and didn’t start a war. He reached a specific conclusion that future One Piece finders may not necessarily reach, which raises a million questions on its own.
Unanswered Questions: Was it because he couldn’t? He was, after all, very sick. Was it that after deliberation, he just chose not to? Or could he not do anything because the timing was wrong?

A True Future. Does anyone out there not think Joy Boy was a D.? My apologies for the quick digression: Joy Boy was able to prophesize hundreds of years in to the future that someone would eventually fulfill his promise to the inhabitants of Fishman Island. Legend foretold that someone would guide Shirahoshi in some manner, and the Sea Kings were told by somebody that they would pull the Noah to fulfill some sort of purpose/destiny. One of the biggest inconsistencies I’ve found in the manga that needs explaining is why was Ohara allowed to exist for the last 800 years? If the history of the Void Century is so damning to the World Government, why would they not just destroy it right away? I argue that it’s because the World Government somehow knew the “promised time” was coming, and that Ohara became a threat to them only recently. We keep seeing all of these events unfold very coincidentally around Luffy and around his adventure right now.

If this is indeed the case, Roger’s actions gain some rationale: maybe his timing was wrong. One Piece may very well allow its owner to incite a war with the World Government, but maybe Roger knew it was a fight that they couldn’t win or a fight they didn’t want to start. One Piece, therefore, is only usable in a very specific context. If we assume then that when Roger found it the timing was wrong/context was incorrect, we have to ask ourselves what is that context? Or in other words, what has dramatically changed between when Roger found One Piece and now?

Shirahoshi’s Powers Have Awakened. Or better yet, Poseidon has been reborn. Now that an Ancient Weapon has been awakened, that the timing for some major event is now possible or viable. Maybe now, One Piece is useable. Maybe with the power of Poseidon on your side, you can start that war and win. No matter what the case, Poseidon certainly poses a huge threat to the World Government, and Shirahoshi will be undoubtedly hunted by them very, very soon.

Here’s Where Things Get Tricky. We don’t know what One Piece is and it’s definitely fun to speculate. Given everything that we’ve discussed so far, it seems to me that One Piece might just be another Ancient Weapon or the history of the Void Century. Whatever it is, it seems to have to be tangible and a threat.

The Will of D. then, in this context, might just be the only thing that stands between the Ancient Weapons from destroying the world. If Shirahoshi goes crazy or gets captured/taken hostage and used, by being able to communicate with Sea Kings, Luffy will be in a unique position to stop them from destroying everything. Likewise if the Will of D. is required to find/use One Piece and One Piece is in fact a third (or even fourth) Ancient Weapon, Luffy might be the only person capable of preventing its abuse. These weapons have been built up to be insanely powerful and have withstood the test of time, by virtue of them still being a threat today. The carriers of the Will of D. may be the only people that can stop the world from being destroyed by the Ancient Weapons!

Alternatively, one of Luffy’s well documented strengths is something Mihawk very famously talks about: his ability to inspire people and gain allies wherever he goes. If One Piece is in fact the history of the Void Century, the next logical step would be to take down the impossibly powerful Gorosei. Here’s where this theory gets interesting: there are five of them and Luffy certainly won’t be taking them all down him self. But with the help of the Ancient Weapons, maybe he can get enough support to take them all down. By befriending Shirahoshi, he could have the help of the Sea Kings to take one of them, Shanks to take another, Marco and what’s left of Whitebeard’s crew to take another, Garp and his own crew to take down one more, and Luffy himself would take down the big daddy. No matter how the series ends, it seems to me like the Gorosei are going to be heavily involved as either the last bosses, if you will, or something very close to it! Added 12/11/2011: About that last Gorosei battle, we actually think that the Elbaf Giants will come to Luffy’s aid. Really one of the only reasons I think this is because Oda didn’t forget about them when writing Chapter 0: Strong World, which probably means we shouldn’t forget about them either

Now obviously this is all still a theory but my hope is that seeing my line of thinking inspires you all to come up with something better/more possible! Because I just re-read everything I posted and it seems anti-climactic There’s a little bit more to be added and most certainly some more editing but I wanted to get this up because I promised you guys I would! I’ll update the front page/twitter with any dramatic updates to this page – hopefully something with a thrilling conclusion Thanks for reading guys. Hope it wasn’t too long or too uneventful for you. What do you all think?

Update (12/11/2011): This is for myself. As I’m reading, I just want to keep track of all the panels where the Will of D. is mentioned, among other things.

http://www.mangafox.com/manga/one_piece/v58/c570/5.html

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TTTTTTLLLL;DR

1. Roger found One Piece but didn’t use it to incite a war because the timing was off.
2. The timing is now right because Shirahoshi/Poseidon has awakened.
3. One Piece requires the Will of D to use.
4. The carriers of the Will of D are those who protect the world from the Ancient Weapons.
5. The Gorosei will be taken down by a massive, Luffy led army.