One Piece has numerous unresolved plot points, among which the impact of D clan stands as one of the most important in the story. People who bear "D." in their full names form a nexus connecting a lot of different characters, such as Luffy, the protagonist, with Blackbeard, the antagonist, all destined to shape events over the world.
In that regard, the recent One Piece theory suggests something that has been mentioned throughout the years, which is the fact that Luffy and his friends are going to destroy the Red Line and unite the entirety of the seas. This could be not only the culmination of Luffy's journey but also quite likely something that could date back to Joy Boy and the Ancient Kingdom as a whole.
Disclaimer: This article contains spoilers for the series. Any opinion expressed here belongs to the author and not Sportskeeda as a whole.
Explaining how the D clan could destroy the Red Line at the end of One Piece
This theory suggests that several centuries ago, the D. Clan, harbored the ambition to create a world where people's dreams could come true. However, they often struggled in achieving their vision, whether due to the meddling of the World Government's or simply life itself. It was during this period that Joy Boy arrived, aided by the people of the Ancient Kingdom, in beginning to make a change in the world.
There exists the possibility that Joy Boy somehow created Devil Fruits as a way to grant people their wishes, which would fit with Dr. Vegapunk's explanation of how their origin during the Egghead arc. However, the World Government, led by Imu, eventually found a way to defeat Joy Boy and possibly destroyed the Ancient Kingdom - a likely event of the Void Century.
Now, with the resurgence of the D. Clan, both Luffy and Blackbeard are at the helm, inheriting Gol D. Roger's dream and achievements from decades ago. This theory points out that the series is going to end with Luffy destroying the Red Line, thereby merging the seas into one, something akin to the legendary All Blue sought by Sanji. The merge would symbolize the realization of a world where dreams do come true.
The challenges of the ending
The One Piece ending is going to be a demanding situation for author Eiichiro Oda, given the multitude of plot points that require resolution in a satisfying manner. A good example of this are the aforementioned D. Clan, the nature of the Void Century, what happened to the Ancient Kingdom, and how all of that is going to connect with Luffy.
Furthermore, numerous other elements demand attention, such as the nature of Imu and what he or she is, the motivations of the World Government, the threat of Blackbeard, and even what Shanks' perspective on things is. All of this while trying to give the Straw Hats a satisfying conclusion to their respective journeys and goals throughout the series.
Final thoughts
There is a very good chance that the D. Clan wanted to change the world centuries ago to help people achieve their dreams and the World Government stopped them. This could mean that Luffy could potentially destroy the barrier that is the Grand Line to create one big sea in One Piece.
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