In this type of fanfiction, perhaps Natsu discovers a dark secret within the Fairy Tail guild that the higher - ups don't want exposed. So, instead of dealing with the issue, they choose to betray Natsu to keep him quiet. Or, a new member who has some hidden motives could frame Natsu, making the guild think he has betrayed them first. This would lead to their retaliatory betrayal.
One possible storyline could be that Natsu is wrongly accused of a crime within the Fairy Tail guild. Maybe some false evidence is planted against him, leading the guild members to turn their backs on him. Another could be that a powerful enemy manipulates the guild into believing Natsu is a threat, so they betray him. It might also be that there's a misunderstanding about Natsu's powers or intentions, causing the betrayal.
One possible storyline could be Natsu founding Fairy Tail after a great battle where he realizes the need for a guild that stands for true friendship and strength. He then gathers like - minded mages and builds the guild from the ground up.
One possible storyline could be that the OC tries to find Natsu after he leaves Fairy Tail. The OC might have a special bond with Natsu and be determined to bring him back. They could go on a journey where they face various challenges and meet new characters along the way. Another idea is that the OC is actually the reason Natsu leaves Fairy Tail in the first place. Maybe there was a misunderstanding or a conflict between them that led to his departure, and the story could be about how they resolve it.
In some fanfictions, Natsu could be framed by a dark guild as a traitor to Fairy Tail. The dark guild spreads false rumors and evidence, causing Fairy Tail to turn against him. Natsu then has to prove his innocence while also taking on the dark guild that started it all. This would lead to a lot of internal conflict within Fairy Tail and also intense battles between Natsu and the dark guild members.
One possible reason could be a misunderstanding within the guild. Maybe someone spreads false rumors about Natsu, leading others to believe he's done something wrong. Another reason might be a power struggle. If there are those in Fairy Tail who envy Natsu's strength and popularity, they could plot against him to get him out of the way.
One popular storyline could be Natsu and Kinana going on an adventure together to find a rare magical item. This would test their skills and friendship as they face various obstacles along the way.
A common type of fanfiction might be a love story between them. Despite their different personalities, they could gradually fall in love. For example, during a long and dangerous quest, they start to see each other in a new light. Or perhaps a story where Mirajane's past traumas are revealed to Natsu, and he helps her overcome them, strengthening their bond in the process.
One popular storyline is about Natsu's journey to become stronger in the memory of Igneel. He often faces tough battles and overcomes them with the power Igneel instilled in him. Another is where Natsu discovers hidden secrets about Igneel's past that change his perspective on his own life and powers. And sometimes, there are fanfictions that feature Igneel coming back in some form to guide Natsu further in his adventures.
One popular storyline could be Natsu and Laxus teaming up against a powerful dark guild. They have different fighting styles but learn to combine their strengths. Natsu's brute force and Laxus' lightning - based attacks could make for some epic battle scenes.
One interesting storyline could be Natsu and Wendy going on a special mission together. Maybe they have to find a rare magical item that can save the guild. Along the way, Natsu's impulsiveness gets them into some trouble, but Wendy's healing magic and calm nature help them get out of it.
One popular storyline could be Wendy and Natsu teaming up for a difficult mission. Maybe they have to face a powerful dark mage in a remote location. Wendy uses her healing and sky dragon slayer magic to support Natsu, who goes all - out in combat.