One possibility in this fanfiction could be that Naruto gains new and unique combat skills. Monkey D. Dragon is known for his revolutionary ideas and powerful abilities in the 'One Piece' world. Under his training, Naruto might learn different ways of strategizing and approaching battles, perhaps incorporating some of the more unorthodox fighting styles from the 'One Piece' universe. This could lead to Naruto becoming even more formidable, not just in terms of his ninjutsu, but also in his ability to lead and inspire others in a different way, much like how Dragon has an impact on the 'One Piece' world.
In this fanfiction, the dragon could also introduce Naruto to a whole new world or dimension. There, Naruto would face different challenges and enemies. The dragon's training would be specifically tailored to help Naruto survive and thrive in this new and strange environment. He might learn to fly, for instance, or communicate with other mythical creatures, which would be really exciting for the readers.
In addition to Naruto, there could be other characters from the Naruto universe who might get involved in his training with the Dragon Clan. For instance, his friends like Sasuke or Sakura might come to check on him or even be part of some joint training sessions. And there could be rival characters within the Dragon Clan who don't like Naruto being there and cause trouble for him during his training.
In this fanfiction, Naruto might gain unique powers from the Dragon Clan training. Maybe he'll learn special dragon - inspired jutsu that give him an edge in battles, like breathing fire or having enhanced speed and strength.
Well, it might enhance his physical strength a great deal. The dragon could teach him unique combat moves, like some dragon - style strikes. Also, his chakra control could improve as the dragon might have special techniques for that.
Naruto's physical abilities would obviously improve. But more than that, his spiritual side could be enhanced. The dragon might teach him about the balance between power and self - control. This could lead to Naruto having a more refined chakra control and a deeper understanding of the nature of power. As a result, he would not only be stronger in combat but also a wiser leader and friend in the story.
Perhaps the plot starts with Naruto's village facing a new and unknown threat that their traditional ninja skills can't handle. Monkey D. Dragon somehow arrives in the Naruto world and offers to train Naruto as he sees similarities between Naruto's struggle for peace and his own. During the training, Naruto discovers new ways of using his chakra and also learns valuable lessons about leadership and freedom from Dragon. This then helps him when he returns to his world to face the threat.
Well, Naruto would probably gain some really unique magical abilities. Fairy Tail mages are known for their diverse magic, and Naruto could combine his chakra skills with something like Fire Magic or Celestial Magic. He might become even more powerful in combat, with new ways to attack and defend.
Naruto would gain better combat awareness. Kurama's experience in battles can be passed on to Naruto. He'll be able to read his opponents better, know when to attack and when to defend. This will make him a more formidable opponent in combat situations.