It could be another male character who is also interested in the same person as Natsu. This would create a love triangle. He might be from a different guild or have a different type of magic, and the competition between him and Natsu for the girl's love would be a major part of the story.
The power - struggle theme is quite common. Each trying to prove their power is greater. Then there's the theme of self - discovery. As they interact, they learn more about themselves. And mystery is also a theme. There could be a mystery that only they can solve together in the fanfiction world.
If we consider the magical aspects of their powers, a Dragneel's power might be more raw and instinctive, while a Fullbuster's power could be more controlled. When they interact, the Dragneel's power could add intensity to the Fullbuster's ice spells, making them more powerful and long - lasting. Or the Fullbuster could use his ice to contain and direct the Dragneel's fire, creating a more focused and destructive force.
One thing that might make it unique is the combination of different fictional universes. Naruto and Etherious come from very different settings, so the crossover itself is distinct. The character of Dragneel could add another layer of uniqueness if he has a special role or ability in the story.
Well, I'm not sure how widespread it is, but it's possible to find such fanfiction. Writers often like to mash - up different universes to create something new. In a 'Harry Potter is Natsu Dragneel' fanfic, you might expect to see Harry with Natsu's determination and love for his friends translated into the context of the wizarding world. Maybe he'd be more brash and use his 'fire - like' magic in a more aggressive way like Natsu does.
A common plotline is the rescue mission. His friends from Fairy Tail band together to find and save him. Another is Natsu trying to break free on his own. He might use his fire magic in creative ways to escape his bonds.
Another great idea for a fanfiction could be a story where Naruto Dragneel is actually from a different dimension and is sent to the Fairy Tail world for a specific mission. Along the way, he forms deep friendships with the Fairy Tail guild members and together they uncover secrets about both their worlds that no one knew before. His Naruto - like determination and Dragneel - like powers would make for a very dynamic character in this Fairy Tail universe.
A theme that is quite prevalent is the idea of sacrifice. In many fanfictions, either Natsu or Lucy is put in a position where they have to sacrifice something for the other. It could be their own safety, their magic, or their dreams. Also, the theme of growth is common. They both grow as characters, learning more about themselves and each other as the story progresses. This growth can be in terms of their magical abilities, but also in their emotional maturity.
One great 'etherious natsu dragneel and lucy fanfiction' is 'A Bond Beyond Magic'. It beautifully explores their relationship in a world where they face new and unexpected magical challenges together. The way it develops their characters and the unique magical situations they encounter make it a very engaging read.
In the 'etherious naruto dragneel fanfiction', it could be that the author is creating a whole new adventure. Maybe Naruto finds himself in a world full of Etherious and has to team up with Dragneel to face some common enemy. The fanfic could play around with different magic systems from both Naruto's ninja world and the Etherious world. It might also delve into the backstories of the characters to give them more depth and make the story more engaging for readers who are fans of both universes.