Part of what makes a series like One Piece so fun to theorize about is the handful of mysteries about its world and characters that haven't been solved yet. Among the biggest of those mysteries -- because there's still so much we have yet to learn about it, even after all this time -- is the Will of D.

Throughout One Piece's run, more and more characters possessing the middle initial "D" have cropped up, all starting with the series protagonist, Monkey D. Luffy. In the SBS corner of Volume 8, a fan asked Oda what the "D" in Luffy's name stood for, to which he responded "I cannot answer that question. I can't answer it... yet. Please just read it as 'D' and don't think too deeply into it for now." Then, the first time it's acknowledged as more than a middle initial is when Dr. Kureha sees the Straw Hats off from Drum Island. She refers to the Pirate King by his true name, Gol D. Roger, and that Chopper will have quite the adventure ahead of him as "the Will of D lives on."

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The mystery of "D." is still unraveling, but we aren't entirely in the dark about what surrounds it. We do know "D." is inherited, since Luffy, his father, Dragon, and his grandfather, Garp, all have "D." in their name. The other characters with "D." in their name include Portgaz D. Ace and his mother, Portgaz D. Rouge, Trafalgar D. Water Law, Marshall D. Teach and Rocks D. Xebec.

Those with the Will of D. share the unusual trait of smiling in the face of death. Roger smiled at the time of his execution, Saul smiled at Robin before Aokiji froze him solid and Ace also smiled before dying in Luffy's arms. All of them got what they set out to get in one way or another, so it could be a sign that those with "D." will die without regrets or fear of death.

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Portgas D. Rouge One Piece

Often, it seems those with the "Will of D" are rebels who rail against the conformity the World Government forces on people. Out of the ten One Piece characters known to have "D.," only two are affiliated with the marines -- Monkey D. Garp and Jaguar D. Saul -- and just one is a civilian (Portgaz D. Rouge), with the rest consisting of pirates or revolutionaries. Yet, even still, these characters end up either falling out of line or committing treason against the government. After releasing Nico Robin's mother from custody, Saul would travel to Ohara alone to warn the people of the approaching Buster Call, while Garp had gone against government orders many times in the past and even declined a promotion to Admiral position.

In Rouge's case, she would give birth to the Pirate King's son at a time when the WG was hunting down every pregnant woman with any potentially association with Gold D. Roger. Although it's maybe not the "Will of D." that compels these people to stand against the fascist control of the WG, perhaps these individuals were fated to stand against the WG, thus drawing the "Will of D" to them. Regardless, this dislike of authority has its roots in one source: the Celestial Dragons.

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According to Corazon, those who possess "D." are considered enemies of the Celestial Dragons. The descendants of the people who created this world, these nobles are so egotistical they also call those with "D" by another name: "The Natural Enemies of God." Whatever the case, the feud between the Celestial Dragons and "D." has spanned centuries and most likely has something to do with the Void Century as well.

The true meaning of D. and the greater details that surround it are still shrouded in mystery, but knowing Oda, we will know what "D." is before One Piece reaches its end.

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