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.
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.
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.
In the 10 - years of this fanfiction, Natsu and Mia could be part of a prophecy. They have to fulfill certain tasks to prevent a great disaster. Their journey would be filled with self - discovery, as they learn more about their own powers and their roles in the Fairy Tail universe.
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.
One possible reason could be that he was wrongly accused of a serious crime within the guild. Maybe some powerful and influential members believed he was a threat and pushed for his banishment. For example, if there was a string of mysterious attacks and Natsu was framed as the culprit due to his often wild and uncontrollable nature in battle.
It could be about Natsu having left Fairy Tail for some reason and then reuniting with the guild in a very unexpected way. Maybe he has new powers or a different outlook on life that causes some friction and also some amazing moments of reunion and growth within the guild.
If Natsu were trained by Acnologia, he might face a moral dilemma. Acnologia is a feared and often seen as an evil force. Natsu has always been on the side of good. So, during the training, he would have to decide whether to follow some of Acnologia's more ruthless ways of using power or stay true to his own values. This internal struggle could add a lot of depth to his character. Also, his relationships with his friends in Fairy Tail might be strained as they might be worried about the influence Acnologia has on him.
One possible plotline could be Natsu trying to prove his innocence. Maybe he was wrongly accused of a serious crime within the Fairy Tail guild, like endangering the lives of other guild members during a mission. He then sets out on a journey to find evidence that clears his name while also facing various challenges and enemies along the way.
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.