Well, perhaps the story could start with Natsu having a strange encounter that begins his transformation into a dragon. Maybe he discovers some ancient magic or a hidden power within himself that is related to dragons.
Maybe it could involve Natsu having to go through some really tough trials to prove himself worthy of becoming the Fire Dragon King. For example, he might have to battle powerful enemies that are related to the dragon world's ancient secrets.
Maybe Natsu discovers a new magic spell that accidentally turns him into a dragon. He then has to figure out how to reverse it while dealing with the new powers and instincts.
In this 'natsu becomes a girl fanfic', it could center around the idea that Natsu as a girl discovers a whole new side of the magical world. Since he is now a girl, he might be able to access certain areas or knowledge that were previously off - limits. He could also form new relationships with other characters who see him in a different light.
Well, it could be about Natsu suddenly finding himself in a situation where he has multiple dragon companions who are all attracted to him. Maybe he has to deal with their different personalities and powers while also trying to figure out how he got into this harem situation in the first place.
One possible plot could be that Natsu is cursed by a dark wizard. This curse slowly transforms him into a fire dragon. As he changes, he struggles to control his new dragon - like instincts and powers. His friends initially fear him but then realize they need to help him break the curse.
Well, perhaps the plot could involve Natsu's transformation being a result of some powerful magic or a dark curse. He might struggle to control his new dragon form at first, causing chaos among his friends and allies.
Well, it could be about Natsu's journey to becoming a Dragon God and how he attracts a harem along the way. Maybe he gains new powers that make him irresistible to certain characters.
One possibility is that Natsu discovers some ancient dragon magic that transforms him into a Dragon King. He might gain new powers like the ability to control all types of dragons or access to long - lost dragon knowledge. This could lead to him having to face new enemies who are threatened by his new - found status.
Another option is a rival dragon slayer who sees Natsu's transformation as a threat to his own status. This rival could try to stop Natsu from fully becoming a dragon or try to defeat him to prove his own superiority.
Well, perhaps the plot could involve Natsu hiding his dragon identity from his friends in the guild. He might be worried about how they'll react if they find out. Maybe there are certain powers that come with being a dragon secretly that he has to learn to control without anyone noticing.