One possibility could be that Natsu is attacked due to a misunderstanding within the Fairy Tail guild. Maybe a new member misinterprets Natsu's actions as a threat and attacks him in self - defense.
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.
Perhaps an older, disgruntled member of Fairy Tail who has some hidden grudge against Natsu. Maybe Natsu unknowingly got in the way of this member's plans or achievements in the past, and now they see an opportunity to get revenge. They might use their knowledge of Natsu's fighting style and weaknesses to launch a surprise attack within the guild.
Well, one possibility is that Natsu could join Fairy Tail in a different way than in the original story. Maybe he has some special mission before officially becoming a member. For example, he has to prove his loyalty by helping an elder member with a personal problem.
One possible plot could be that there is some sort of misunderstanding or dark magic at play that causes Natsu and Mavis to fight. Natsu, being hot - headed, jumps into the fray without fully understanding the situation. Mavis, on the other hand, is trying to figure out a way to stop the fight without harming Natsu. As the battle progresses, they both start to realize that they are being manipulated and then team up to face the real enemy.
One possible plot could be that the guild goes into deep mourning. Gray might blame himself, thinking he could have protected Natsu. Lucy could be in a state of shock and disbelief, and she might start writing in her diary about all their adventures, as if reliving the memories to deal with the pain.
One possible plot could be that Natsu has been living a different life away from Fairy Tail. Maybe he was raised by another guild unknowingly. When he finally joins Fairy Tail later, he has to prove himself to the existing members who are skeptical of his late arrival. He might have unique magic skills he developed elsewhere that surprise everyone.
The story could start with Natsu being tricked by a powerful enemy and sent to a far - off and unknown land. As a lost Fairy Tail member, he would have to rely on his instincts and the little magic he has left. He might meet new allies who help him in his journey back to Fairy Tail, all while learning important lessons about friendship and the true strength of his guild.
Another plot could revolve around Natsu being the new kid at school and having to earn the respect of his classmates. He gets into various battles and challenges, not just physical ones but also magical duels of wits. His friends from Fairy Tail might visit the school from time to time to help him out or just to see how he's doing. And as he overcomes these challenges one by one, he gradually becomes a respected and feared figure at the school, all while still maintaining his fun - loving and loyal nature.
One possible plot could be that Natsu and Mirajane join Fairy Tail at different times. Natsu might bring his usual enthusiasm and powerful fire - based magic. He could quickly get into all sorts of adventures, making friends and enemies alike. Mirajane, on the other hand, could use her Take - Over magic to be a great asset in battles. Their joining could lead to new team - ups within the guild, like Natsu and Mirajane going on a mission together to stop a dark wizard who is causing chaos in a nearby town. They'd face challenges, but their combined skills would help them overcome the odds.
In the fanfiction, perhaps Natsu has a fateful encounter with a powerful magical being. This being could transfer some of its essence or powers to Natsu. For example, it might be a dragon from a different dimension that gives Natsu the ability to not only control fire on a much larger scale but also to manipulate other elements to some extent, thus making him OP. He could then use these newfound powers to take on the toughest enemies in Fairy Tail, like the dark guilds and their powerful leaders.