There is a fanfiction called 'Natsu and Happy's Unexpected Journey'. In this story, they stumble upon a time - traveling spell and end up in the past. They meet younger versions of their Fairy Tail friends and have to be careful not to disrupt the timeline. It's full of action and heartwarming moments.
One possibility is that they leave to explore a new land filled with unknown magic. They might be on a quest to find a powerful magic item that could help Fairy Tail in the future.
One interesting fanfiction could be where Natsu and Happy discover a hidden magic that only they can use. This new magic leads them on an adventure to a far - off land filled with strange creatures. They have to use their combined skills and the unique bond between them to overcome challenges.
A powerful dark wizard who has a vendetta against Natsu. Maybe he blames Natsu for something that happened in the past, like the destruction of his dark guild by Fairy Tail. So, when Natsu and Happy leave Fairy Tail, he sees it as an opportunity to get revenge.
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.
Often, it could be because of a false accusation. Maybe someone framed Natsu for a crime he didn't commit, like stealing a powerful magical artifact from the guild. So, to maintain peace and order, the guild leaders had no choice but to banish him.
Lucy could be a main character. She was always close to Natsu in the original Fairy Tail. So when Natsu returns as an 'ex' and meets the guild again, she would likely play a big role in how he is received and in the development of the story.
One possible aspect of a Fairy Tail Natsu and Tartaros fanfiction could be Natsu's battle against the powerful foes in Tartaros. He might face new and terrifying enemies that test his limits. His dragon slayer magic would be put to the extreme, and perhaps he discovers new powers along the way.
In fanfictions like this, the character development of Natsu within the context of Sabertooth is interesting. He could learn new magic techniques from them or teach them his own unique brand of Fairy Tail spirit. It might also explore how the different cultures of the two guilds clash or blend.