With One Piece chapter 1044, Eiichiro Oda shocked the fans by revealing one such mystery pertaining to Luffy's Devil Fruit. To everyone's surprise, Luffy, who was always believed to be a user of the Paramecia type Gomu Gomu no Mi, is actually a user of a Zoan type Devil Fruit. Furthermore, this isn't just any Devil Fruit, but a power described to be "the most ridiculous" to exist in the entire story.
Luffy's Gomu Gomu no Mi is the very first Devil Fruit that fans saw in the story. Stolen by Shanks, the fruit was, at the time, just an average power with no significance attached to it. However, with time, fans got to know more about Shanks' peculiar nature. For him to steal Devil Fruit wasn't normal unless there were some motivations behind it. In the Wano Country arc, Who's Who revealed that Shanks stole the Devil Fruit from his ship when he was guarding it as a member of the CP9. Quite clearly, the importance of the Devil Fruit was established since the World Government wanted to grab ahold of it.
In the fight against Kaido, Luffy finally managed to awaken his Devil Fruit, and immediately afterwards, fans were told by the Gorosei that Luffy's Devil Fruit is one that they've tried to hunt for 800 years yet failed to obtain. More importantly, the fruit's real name was hidden by the Government to hide its significance. In a shocking turn of events, it was revealed that the Gomu Gomu no Mi is actually a Zoan type of Devil Fruit and its real name is the Hito Hito no Mi, Model: Nika. Although it may be confusing to some as to how that's possible, the basis for this was set quite early in the series.
Sengoku, the former Fleet Admiral of the Marines, has the power of the Hito Hito no Mi, Model: Daibutsu, a power that turns him into a giant Buddha. For Luffy, the transformation allows him to turn into a figure many revere as a god – Nika. Interestingly enough, nobody ever realized that Luffy's fruit was a Mythical Zoan since these fruits are known to have special abilities. For instance, Marco's fruit has the blue phoenix flames that almost act like a Logia ability, and Sengoku can produce powerful shockwaves which is an attribute of the Paramecia types. In Luffy's case, the Hito Hito no Mi, Model: Nika turns the user's body into rubber, which is akin to a Paramecia power. Using this power, the World Government were able to successfully hide the true name of the Gomu Gomu no Mi in the hope that they would eventually gain the fruit.
The Hito Hito no Mi, Model: Nika might have the name of the god but its powers depend on the user of the ability. In its regular state, the fruit allows Luffy to become a rubber man and fight with great freedom in combat. More importantly, the biggest power that this fruit offers is its ability to spread joy and laughter to everyone and liberate those who are oppressed. As explained by one of the Gorosei, this makes the user a "Warrior of Liberation."
While this ability is quite interesting, it is far from the most overpowered ones in the world of One Piece. After all, it cannot destroy the planet like Whitebeard's Gura Gura Gura no Mi, or take away the power of Devil Fruits like the Yami Yami no Mi. The Hito Hito no Mi, Model: Nika is a pretty standard power, however, its Awakening is what makes it truly dangerous. Awakening strengthens the body of the fruit user even more and allows them to fight with even greater freedom. The powers of this fruit are so bizarre that they break the very laws of nature in every way possible. Its title of "the most ridiculous ability" is very much deserved.
The Hito Hito no Mi, Model: Nika makes Luffy's heartbeat sound like "the drums of liberation" and turns his body more rubbery. It seems that he doesn't need to rely on air for inflation anymore and Haki isn't needed to increase his power through compression. This fruit grants strength that is tremendous enough for him to treat Kaido, one of the Yonko, like he's just another pirate.
Like the standard paramecia awakenings, the Nika fruit allows Luffy to turn his surroundings into rubber with rather ease. In fact, he can even repel attacks with his rubber surroundings with ease. The scariest part about his awakening is that it also grants him a "pure white" transformation which seems to allow him to break the very laws of nature itself. Luffy's awakening allows him to do things like run in mid-air leaving fire tracks behind, alter the shape of his body freely, and do things like affect people in his surrounding with his awakening.
In his fight against Kaido, Luffy was able to turn Kaido's body into rubber and pull off ridiculous feats like escaping from his eyes and punching his face by turning him into rubber. Without a doubt, the Hito Hito no Mi, Model: Nika is a scary ability that allows the user to fight with tremendous freedom which is only limited by their imagination. Being in possession of Luffy, the man who is the epitome of freedom itself, this fruit is ridiculous in every sense and fans are still to see the best of its powers.