Well, it could be incorporated as a new form of magic. A character in Fairy Tail might discover an ancient spellbook that has a similar power to Kamui. This discovery could change the power dynamics in the guild and lead to new adventures.
One idea could be a crossover where a character from Fairy Tail somehow gains the Kamui ability. They could use it in battles against dark guilds in the Fairy Tail world, opening portals to surprise enemies or escape dangerous situations.
It could be Sasuke. Since he has the Sharingan which is related to the Kamui ability in a way. He could be transported to the Fairy Tail world and his brooding and powerful nature would make for an interesting dynamic as he tries to find his way back home while getting involved in Fairy Tail's affairs.
Well, perhaps the fanfic could focus on a magic item in Fairy Tail that has a connection to the Kamui power from Naruto. A group of Fairy Tail wizards and a Naruto character team up to figure out the secrets of this item. They might face challenges like rival guilds trying to steal the item and ancient spells that are linked to the Kamui - like power. As they go on this adventure, they also learn about each other's worlds and grow as a team.
In that fanfiction, it might be designed that way. Naruto has incredible powers in his own series, like his various jutsu. If translated into the Fairy Tail world in fanfiction, his skills could potentially make him very powerful. But it also depends on how the author of the fanfiction interprets and balances the power systems of both universes.
The Sharingan in such a fanfiction could be used as a tool for a Fairy Tail character to gain an edge in their battles. They might initially struggle to control it, but as they learn more about it, they become a formidable force. For instance, they could use the Sharingan's genjutsu abilities to deceive opponents in the Fairy Tail battles.
In the Fairy Tail world, Naruto would bring his unique ninja abilities. For example, his shadow clone jutsu could be used in creative ways during battles or to perform tasks. He would likely befriend Natsu because they both have a passion for fighting and protecting their friends. Naruto could also introduce new combat styles to the Fairy Tail guild, which might change the way they approach battles.
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 using Kamui could change the power dynamics in the Naruto universe in the fanfiction. His battles would become more unpredictable. For instance, against strong opponents like Madara or Kaguya, Kamui could be used in creative ways. He could use it to send parts of their attacks to another dimension, or quickly dodge attacks and counter - attack from unexpected angles. It also might make his allies view him differently, as this new power is something very different from his normal ninjutsu.
Well, Naruto's ninjutsu skills would be quite a novelty in the Fairy Tail world. His shadow clone jutsu could be used in some really creative ways during battles, like overwhelming opponents with a large number of clones. Team 7 as a whole would bring a different dynamic. Sasuke's sharingan could give them an edge in detecting magic and illusions. Sakura, with her medical skills, could be a great asset in treating wounded mages. And Kakashi, with his experience and wide range of jutsu, would be like a mentor figure to the Fairy Tail members, teaching them new strategies.