The Fairy Tail guild members who supported Natsu's exile could be antagonists. They might believe in false accusations against him or have their own motives for wanting him out of the guild, like jealousy of his power or popularity.
It could also be a story about Natsu's personal growth during his exile. Without the support of his Fairy Tail friends initially, he has to rely on his own strength and wits. He might discover new magical abilities or face challenges that test his character, and in the end, he either returns to Fairy Tail as a changed and stronger wizard or decides that his new path outside the guild is better for him.
One idea could be that Natsu is exiled due to a false accusation of using dark magic. He then has to journey alone to prove his innocence, encountering new friends and foes along the way. Maybe he discovers a new form of magic during his exile.
Maybe an old acquaintance from Natsu's past that we haven't seen much in the original Fairy Tail story. This person could be a powerful but reclusive mage who decides to help Natsu out of respect for his father or some past debt. They could offer Natsu shelter and train him in new forms of magic to help him face the challenges during his exile.
In some fanfictions, creative liberties are taken and Natsu could potentially be reimagined as Mia. But in the original Fairy Tail, they are distinct characters.
In this fanfiction, Naruto's exile could be due to political reasons within the Fairy Tail guild. There might be a faction that fears his growing influence. Since Naruto is used to being an outsider in his own world too, he might initially be heartbroken but then decides to prove himself outside the guild. He could start his own group of misfits, similar to how he was part of Team 7 in his original story.
Yes, in a lot of Fairy Tail fanfiction, Natsu can be overpowered. Writers often like to amp up his powers for more exciting storylines. For example, they might give him new fire - based abilities or make his existing ones even stronger to defeat more powerful foes.
In fanfiction, Natsu's age can vary greatly. Some authors might keep him at his canonical age from the original Fairy Tail series, which is around 17 - 18 years old at the start. However, in alternate universe fanfictions, he could be older or younger depending on the plot. For example, in a time - travel based fanfic, he could be much older if the story takes place far into the future or much younger if it goes back to his childhood days.
It could change the whole dynamic of the relationships in the story. For example, his interactions with other characters like Lucy would be very different.
One possible story could be about Natsu and Mia's adventures over the 10 years. They might face powerful enemies together, with Natsu using his fire - dragon slayer magic and Mia having her own unique skills. Their friendship could grow stronger as they overcome various challenges.