You may remember my first idea for One Piece being about the X-men, but this time I'm going more for an insert character idea, so no characters from other media (That doesn't mean I won't draw upon said characters' powers as inspiration). As you might have guessed from the title, this MC is going to be gaining powers from a true Devil Fruit.
Born on a hidden island in the East Blue, our MC spends his youth as a lackey to a small band of pirates, ones who haven't even managed to get a bounty yet. While he is treated well enough, he gets meals (though he is the one that cooks) and a small amount of pay. Any mistakes, however, are quickly met with a lashing from the captain. The entire crew is subject to this punishment, and they have been growing more and more resentful, but they aren't strong enough to beat the captain. All this culminates in them raiding a small naval base, and finding a Devil Fruit. They don't know understand what it is, as most, if not all, the crew were gathered from isolated islands with no real contact with the outside. They leave the Fruit with the MC so that it can be used for a meal later on. Since he has never come across such a strange fruit, he decides to take a bite to try and figure out what it could be used for. As you probably know, it is an immediate assault on his taste buds, he nearly spits it out but something in the back of his mind compels him to swallow it. Choking it down, he feels something within himself change, though he is unsure exactly what did. The Captain, being from a large country, knew what the crew had picked up, but was unable to get to it before it was handed off to the MC. Witnessing the boy eat what was essentially his golden ticket, the pirate flew into a rage. The MC is quickly attacked, while the crew members attempt to stop the captain. They all tell the protagonist to run, in hopes of sparing him from the gruesome death the captain would inflict upon the young boy. The MC then decides to become the captain of his own crew and later kill the bastard, training his powers for years, until adulthood, when he finally heads out on his personal journey: His goal is revenge against his old Captain and becoming the strongest.
So a little bit of free plot out of the way, let's talk about his Devil Fruit. As many of you have already guessed, it would be a Mythical Zoan Fruit, The Hito Hito no Mi, Model: Asura. You probably already know where this is going but, I was thinking of basing this fruit's abilities off of Asura's Wrath, at least partially. So in his hybrid form. The MC will take on some similar features to Asura, such as white spiked hair, and red eyes as well as gaining some increased muscle definition. In his complete transformation he gains all of Asura's appearance including his golden arms. In this state he has access to further forms like Mantra and Destroyer, though these should be left for when the MC awakens the Devil Fruit. He is also freely able to generate new arms and control them perfectly. As for specific abilities, he has tremendous strength and durability, with his agility not far behind, and the use of a form of energy which he can form into projectiles. In the game this energy was called Mantra, but that name has to be changed to something else because of Enel.
So, some of you may ask why Asura from Asura's Wrath, well it's because the mythological asuras are pretty esoteric, their abilities aren't standardized or well-known. I figured that the game made his powers very clear and I wanted to roll with that. And, yes, I'm aware that Zoro also has asura related powers, but he's only mimicking the depictions of these mythological beings. That's why I feel like this has some potential, and I definitely think plenty of people would read.