Many people theorize that Imu is a man possessing a woman's body, but what if it's the other way around?
Ever since the anime gave Imu a voice that sounded like both a masculine and feminine voice speaking at the same time, the idea that Imu is a body being possessed by another individual has grown even more popular. The most popular theory branching from this idea is that Nerona Imu is possessing the body of Queen Lily. But what if it’s actually Nerona Imu who’s being possessed?
Something we’ve seen commonly hinted at in One Piece*,* but very rarely shown directly in the story, is the idea of Devil Fruit awakenings causing the Devil Fruits to take over their users. We see this once with the Jailer Beasts in Impel Down, but never again, unless we already have.
Jailer beasts are Zoan users taken over by their Devil Fruits
What if Nerona Imu, one of the original 20 kings who founded the World Government, was taken over by his Devil Fruit 800 years ago? My reasoning comes from this: I think there’s a discrepancy between the way Celestial Dragons refer to Imu and the way Imu refers to themself. Imu exclusively calls themself “Mu,” while the Celestial Dragons call them Im or Imu. This may be because the CDs still perceive Imu as Nerona Imu, but his body has actually been taken over by his fruit. How aware the Celestial Dragons are of Imu’s true nature is unknown.
If Nerona Imu was taken over by his Devil Fruit, that of course begs the question: who is the entity (Mu) from this Devil Fruit that has taken him over, and why do I think it’s a woman?
In this theory, I think it makes the most sense for the entity to be the sea god from the Elbaf mural, due to the sequence of events. The forest god sending forth devils could be interpreted as the creation of Devil Fruits. After this, Nerona Imu, in conflict with Joyboy and the Ancient Kingdom, gets his hands on the sea god Devil Fruit, which is tied to an ancient entity from the First World (Mu). Over time, the fruit awakens and consumes him. The Void Century happens (caused by the "sea god" rampaging), and we arrive at the present day. The extent to which Mu has taken over Nerona is unknown. It could be complete possession, but I like to imagine something more like a merge; I think their goals were ultimately aligned, and Nerona may have allowed himself to become one with Mu.
Mu could be the sea god from the Elbaf Mural
So who exactly is Mu? I think Mu is a key figure from the First World, the mythological arch-nemesis of Nika. If you’re familiar with OP theories, you may have heard of the myth of the lost continent Mu. In the legend, Mu was a continent called the “Motherland of Man,” home to an advanced civilization. It was destroyed by volcanic eruptions and earthquakes, causing it to sink into the sea.
The volcanic eruptions immediately make me think of the hellflame serpent described in the First World. And of course, earthquakes and sinking things into the sea are Imu’s whole shtick. Mu being the “motherland of man” could translate in One Piece to Mu being the queen of an advanced civilization that “seized the forbidden sun.” Nika arose afterward to oppose Mu, and after a great battle Mu was victorious, but not before Nika did something that allowed the earth god and the hellflame serpent to destroy Mu and her civilization, sinking them into the sea.
An unknown number of years later, the Second World exists, and another great technological kingdom emerges, this one far more benevolent. A scientific revelation leads to the creation of Devil Fruits, which manifest dreams and legends. Joyboy leads the kingdom, but is met with rebellion by an upstart prince from one of his provinces: Nerona Imu. Nerona secretly wishes to rule the world and rallies 19 other monarchs by persuading them to rebel against Joyboy. At some point in the conflict, he eats the Akuma-Akuma no Mi, Model: Mu (Mu had become perceived as a demon in the legends of the Second World). After this, Joyboy obtains the Nika Fruit, as Nika rises once again to oppose his ancient enemy. Events unfold; Mu takes over Nerona and defeats Joyboy, but Joyboy promises that Nika will return one final time to crush Mu for good. Imu, attempting to stop this, seeks to sink the world, the same way Mu was sunk ages ago in the First World, almost as a form of petty revenge. From there, we get the rest of One Piece.
One last thing: I know it’s not canon to the manga, but I have to mention the dual masculine and feminine voices Imu has in the anime. In this theory, the male voice comes from Nerona Imu’s body, while the female voice is the voice of Mu.
In conclusion, I think Mu is the mythological arch-enemy of Nika from the First World. She was the queen of the civilization that seized the sun. Mu and Nika drew in the First World, Nika lost in the Second, but we will likely see Nika triumph over Mu in the Third World, ending the cycle for good. Nerona Imu was the spiritual equivalent of Mu in the Second World, until his body was taken over by the actual Mu.
Anyway, thanks for reading all this, it’s my first time making a One Piece theory, so let me know your thoughts if you have any.
Posted Dec 4, 2025, 2:37 AM UTC