In a WW2 fanfiction, Fairy Tail's magic could also be used for strategic purposes. For example, if a side has access to Fairy Tail mages, they could use their teleportation magic (if any character has such magic) to quickly move troops or supplies. Also, the magic could be used to counter the new and dangerous weapons of WW2. If the enemy has developed some kind of super - weapon, the Fairy Tail mages could use their unique magics to neutralize it. However, this would also bring up moral questions within the fanfiction about the use of magic in a real - world - like war scenario.
If we think about it, an S - Rank Naruto ability in a Fairy Tail fanfiction could also be something that is coveted by the villains. Let's say a dark guild wants to steal the power of Naruto's Sharingan (if a character with Sharingan was brought into the Fairy Tail world). They might think it's an S - Rank power that could help them achieve their evil goals. This would then lead to a big conflict where Fairy Tail has to protect this Naruto - based power from falling into the wrong hands.
Mermaids could be introduced as a new species that live in the deep, unexplored parts of the ocean in the Fairy Tail world. They could have their own magic system related to water and sea life. For example, they might be able to communicate with sea creatures and use them in battles.
One way is to create characters in the real world who possess the magic abilities seen in 'Fairy Tail'. For example, a character could have Natsu's fire - breathing magic and use it to fight crime in a modern city. Another approach is to set up guild - like organizations in the real world where people with different 'Fairy Tail' - inspired powers come together to complete missions or help the community. Also, you could have real - world locations become the settings for 'Fairy Tail' - style adventures, like an ancient forest being the site of a quest for a magical artifact.
Killua could potentially adapt his Nen abilities to the magic system in Fairy Tail. His Lightning Palm, for example, could be seen as a form of lightning - based magic in the Fairy Tail world. He might be able to combine his assassin skills with the magic knowledge of Fairy Tail. Maybe he'd learn some new spells or techniques from the wizards there to enhance his own fighting style.
There could be a deeper interaction where the OC's Sharingan actually evolves due to exposure to Fairy Tail magic. Maybe the strong magical energy in the Fairy Tail world causes the Sharingan to gain new abilities, like being able to see the future more clearly in magical battles or being able to sense the presence of hidden magical items. This would create an exciting development in the fanfiction as the OC discovers and masters these new powers.
If Romeo has teleportation magic, he could use it to surprise Juliet by suddenly appearing in her favorite places. And if Juliet has healing magic, she could heal Romeo whenever he gets hurt during his adventures, showing how their magic supports their relationship. Their magic can be like a language that only they understand, expressing their love and care for each other in a magical way.
Some of the more hot - headed characters in Fairy Tail, like Natsu, might initially be angry at the aggression and violence depicted in the WW2 fanfiction. They would want to fight against the unjust forces in the story. However, the more level - headed ones like Erza would first try to understand the complex political and social situations that led to the war in the fanfiction before taking any action.
Goku's ki - based powers could be seen as a parallel to the magic in Fairy Tail. His attacks like the Dragon Fist could be considered similar to some of the dragon - slayer magic in the series. When he uses his ki blasts, the mages in Fairy Tail might initially mistake it for a very powerful and unknown type of magic. Goku could also learn to sense ki in a way that helps him detect magic users and their power levels more easily.
Naruto's powers have their own unique features. His Sharingan (if he had it in this fanfiction) would give him an edge in perception and combat, which might be different from what the mages in Fairy Tail are used to. But the mages in Fairy Tail have a wide variety of magic types, such as fire magic like Natsu's or ice magic like Gray's. Naruto's powers would need to adapt to this new magical environment. He might be able to create new techniques by combining his ninja skills with the magic he encounters in the Fairy Tail world.
One way could be through a crossover spell. Maybe a powerful mage in Fairy Tail accidentally creates a portal that brings Vegito into their world. Then Vegito's incredible power would be a huge shock to the Fairy Tail guild, and he could either be an ally or a misunderstood foe at first.