Devil Fruits were officially introduced to us at the very beginning of One Piece on July 18, 1997, in Shueisha's Weekly Shonen Jump Issue 24, when the first chapter was published by Eiichiro Oda in the magazine. Since then, Devil Fruits have played a significant role in the story, and they continue to influence the narrative in numerous ways. If there is one rule that Eiichiro Oda had pertaining to Devil Fruits, it is that a water Devil Fruit was not to be introduced in the story due to its inherently overpowered nature.

Water in general is the ultimate weakness of all Devil Fruit users, as once submerged to a significant degree, all abilities are essentially useless. However, with the Elbaf arc in particular, Eiichiro Oda has introduced a water-related ability to us through a potential Hito Hito no Mi, Model: Zaza, the Rain God. The powers of this god have been shown in the Elbaf arc to us already, and needless to say, they are incredibly impressive.

When Eiichiro Oda established Devil Fruits, he slowly incorporated a couple of rules that were always meant to be broken by some overpowered characters later down the line. For instance, at one point in the story, it was established that no one could eat more than one Devil Fruit, as the two devils would fight inside and the user would simply explode. However, then came along Blackbeard, who consumed two Devil Fruits and exists as an anomaly in the series. It was also quite clearly highlighted by Oda that a water Devil Fruit would simply be too overpowered to exist in the One Piece world.

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