Well, it could be that Voldemort somehow gets his hands on a Devil Fruit. He eats it and gains a terrifying power, like the Pika Pika no Mi (Light - Light Fruit). Now he can move at the speed of light and emit laser - like beams. Harry and his friends have to figure out how to combat this new, even more powerful Voldemort. They might seek the help of some ancient magic that can counter the effects of Devil Fruits. And in the process, they discover secrets about the connection between the wizarding world and the world where Devil Fruits originate.
One possible plot could be a wizard accidentally stumbles upon a Devil Fruit while on an adventure in a far - off land. He eats it and gains the power, say, of the Gomu Gomu no Mi (Rubber - Rubber Fruit). Then he has to hide this new power from his Hogwarts friends and teachers at first because he's not sure how they'll react. As he gets used to the power, he starts using it to his advantage in Quidditch, like stretching his arms to catch the Snitch from a great distance. But then dark forces in the wizarding world become interested in his unique power and he has to fight them off with a combination of his wizardry and Devil Fruit ability.
Sure. There are fanfictions that blend the two concepts. They often create unique storylines. Maybe a wizard uses the power of a Devil Fruit to enhance their spell - casting or a character with Devil Fruit powers enters the wizarding world and has to adapt to its rules. It's really creative and offers a fresh take on both universes.
Well, if Harry ate a devil fruit in fanfiction, he might gain some extraordinary powers. For example, if it was a Logia - type devil fruit, he could transform into an element like fire or water. This would completely change his abilities and how he interacts with the world around him. He could use these new powers to fight against his enemies in a whole new way.
It would be very different from the normal Harry Potter stories. It might involve dark magic and a deviation from the moral code of the wizarding world. Maybe Harry would be in a desperate situation and make a really bad choice to summon the devil.
Well, a common trope is the 'culture clash'. This is when the values and ways of life from the One Piece world (due to Devil Fruits) meet the rather different ones in the Harry Potter universe. Also, the 'mystery' trope can be seen often. For example, a Devil Fruit power is a mystery to the wizards and they try to figure out how it works. Additionally, the 'redemption' trope can be applied when a 'bad' character gets a Devil Fruit power and uses it to change for the better in the context of the Harry Potter world.
The fruit basket could be part of a magical competition at Hogwarts. Each student has to use the fruits in the basket to create the most creative spell or charm. The fruits might have hidden properties that are only revealed when certain spells are cast on them. For example, if a student casts a 'revealio' spell on a banana, it might transform into a mini broomstick that can be used for a short flight around the classroom.
Well, in Devil Fruit OC fanfic, the interaction between different OCs with devil fruits can be really engaging. Imagine an OC with a devil fruit that can manipulate gravity teaming up with one who has a devil fruit that can create illusions. Also, the moral implications of having such powerful abilities through devil fruits for the OCs can be explored, like whether they use it for good or are corrupted by power.
One idea could be a story where Naruto somehow gets a devil fruit that gives him the power to control water. He could use it in his battles in the Naruto world, like creating huge water jutsus with the unique properties of the devil fruit power. Another idea is to have a crossover where characters from One Piece come to the Naruto world and Naruto has to deal with the chaos that the devil fruits bring along.
One possible plot could be Dumbledore taking Harry on a magical tour of Hogwarts. He shows Harry secret passages and tells him stories about the founders. For example, they could visit the Room of Requirement together and Dumbledore could explain how it works. This would not only be an educational experience for Harry but also a chance for Dumbledore to bond with him on a more personal level.
It could be used as a plot device to bring characters together. Say a new student arrives at Hogwarts with a fruit basket from their home. The other students are curious about the fruits which are not common in the wizarding world. This starts conversations and friendships. For example, Hermione might be intrigued by a rare magical fruit in the basket and start researching it, which could lead to a new discovery about magic and fruits.
First, think about the OC's backstory. Maybe they got the Magma Devil Fruit by accident, like finding it on a deserted island. Then, decide on their goals. Are they looking for power? Or do they want to use the power for good? Next, introduce some antagonists. It could be other pirates who want the fruit for themselves. As for the plot development, start with the OC learning to control their new power. They could face difficulties like accidentally setting things on fire at first.