Lyon Vastia could be a great character to focus on. He has powerful ice - make magic, but often gets overshadowed by Gray. In a GMG fanfiction, he could have his own moment to shine, perhaps by teaming up with Fairy Tail for a special event in the games.
Warren Rocko is quite underrated. He has that unique telepathy magic. In 'Fairy Tail Last Ages Fanfiction', he could use his magic in more creative ways, like establishing a long - range communication network between different guilds to face a common threat. Also, Jet and Droy. They are always there as sidekicks but could be developed more. Maybe they discover a new form of plant - based magic together and become more powerful.
Macao. As one of the older members of Fairy Tail, he has a wealth of experience. A fanfiction could explore his role in the 100 Year Quest. He could use his connections and knowledge to gather important information or resources. For example, he might know of a hidden library or an old wizard who has information about the quest's next destination.
One idea could be a new team emerging during the GMG with unique magical abilities that no one has seen before. They could bring a whole new dynamic to the competition.
One way they could cross over is through a shared magical element. In Naruto, there are various jutsu which could be seen as a form of magic like in Fairy Tail. And the Grand Magic Games (GMG) in Fairy Tail has a tournament - like structure. So, perhaps a tournament could be set up where characters from Naruto and Fairy Tail participate. The Naruto characters could use their unique abilities like Sharingan or Rasengan, while Fairy Tail mages use their magic spells. This would create an interesting dynamic where different power systems interact.
One idea could be creating an OC who has a unique magic related to the elements but in a very different way from the existing characters. For example, an OC that can manipulate the emotions associated with elements rather than the elements themselves. This could lead to some really interesting interactions during the GMG as they might be able to influence the performance of other competitors by affecting their emotional state related to their magic.
A plot could involve a powerful dark force threatening both the Naruto and Fairy Tail universes. This force could be something that neither ninjutsu nor magic can easily defeat. So, the characters from both worlds must come together. The GMG could be a platform where the first interactions occur. Maybe some Naruto characters enter the GMG under false pretenses to investigate this new threat that seems to be related to the event.
Lucy could also be a key character. She might play a role in understanding the dragons' return, perhaps using her celestial magic to communicate with them or find out more about their motives. Also, she's a main character in the original Fairy Tail, so it's natural for her to be involved in this fanfiction concept. Her relationship with Natsu might also develop further in the context of the dragons' return.
Natsu is often a central character. His fiery personality and powerful magic make him an interesting focus. Writers might explore his relationships with other guild members in new ways.
Develop a really unique backstory for your OC. For example, if your OC has a tragic past that led them to develop their particular magic in a different way. Maybe they lost their family in a dark magic experiment gone wrong and as a result, they have a magic that is both a curse and a gift. This kind of deep backstory will make your OC more interesting and your fanfiction stand out.
Natsu is often a main focus. His impulsive nature and powerful fire magic can lead to all sorts of interesting situations in a fast - paced fanfiction. His relationships with the other guild members, like Lucy, Happy, and Gray, are also central to many storylines.