For decades, when talking about One Piece, the Red Line, a massive red landmass encircling the world, has been impossible to ignore. Although creator Eiichiro Oda has kept its unusual nature a secret, a recent theory is believed to come closest to the truth and aligns with some of the most important prophecies in One Piece.
According to this theory, the Red Line is not just a mountain range but a gigantic living creature inspired by Norse mythology: Jormungandr, also known as the World Serpent.

Eiichiro Oda May Be Preparing a Major Reveal About the Red Line
In Norse mythology, Jormungandr is a monstrous sea serpent that encircles the world and bites its own tail. When it releases its tail, it signals Ragnarok, the end of the world. Notably, when the serpent lets go, the sea rises, a global tide event that has also been foreshadowed in One Piece.

Although Oda has not revealed detailed information about the Red Line, there are many hints pointing to a giant serpent. In the Elbaph arc, it was confirmed that the world was destroyed twice during the era of Nika and once during the era of Joy Boy.
In chapter 1153, Harald asks Ida if she has crossed the “blood serpent.” Ida replies that she crossed the Red Line. Similarly, Dorry and Brogy ominously mention the world ending because the “bloody serpent is stirring.”
It’s possible that during the Void Century, people realized what the Red Line really was as the serpent stirred, bringing massive destruction. The World Government may be hiding the secret of this serpent, which is destined to cause a global flood.
The Red Line’s Secret Could Unlock Key One Piece Prophecies
If the Red Line truly is the World Serpent, this would explain many characters’ motivations and dreams. If the serpent awakens, it might be time for Loki to defeat it, allowing Luffy to focus on facing Imu. The Red Line could also be directly connected to the Will of D. Those who carry the Will of D might have the power to awaken or destroy the serpent, creating the legendary sea known as All Blue.
In One Piece, Sanji’s dream is to find All Blue, the mythical sea where the North, South, East, and West seas converge. What if All Blue was last created when the World Serpent released its tail, causing a catastrophic flood?
It’s important to note that Fish-Man Island lies directly beneath the Red Line, and if the Red Line awakens, the island could be destroyed. Joy Boy once failed to fulfill a promise involving the Mermaid Princess’s power to control Sea Kings and complete something requiring Noah.
Joy Boy likely anticipated Fish-Man Island’s destruction. The plan was to use Noah as a rescue vessel, controlled by the Sea Kings, to bring everyone to safety. However, Madam Shyarly prophesied that the Straw Hat would destroy the island. So, instead of Joy Boy, Luffy might be the one to trigger the World Serpent, leading to Fish-Man Island’s destruction.

Shirahoshi is the current incarnation of the Ancient Weapon Poseidon, and she may activate the Sea Kings to use Noah to bring people to safety. Ultimately, the destruction of the Red Line could also involve Zunesha, the giant elephant carrying Zou island, signaling the world’s complete liberation from its chains.