In this 'natsu turns into a dragon fanfic', a great plotline could be that Natsu's dragon form is different from the typical dragons. His friends, like Lucy, Gray, and Erza, try to find a way to reverse the transformation at first. But as they see the potential in his new form to fight a greater evil, they change their minds and instead help him master his dragon powers. This could involve a series of adventures where Natsu has to learn to fly, breathe different types of dragon fire, and communicate with other dragon - like creatures.
Obviously, Natsu would be the main character as he is the one turning into a dragon. His friends like Lucy, Gray, and Erza are also likely to be main characters. They would play important roles in either helping Natsu deal with his transformation or being affected by it in some way.
Another plotline might involve the dragon slayers teaming up against an ancient evil that threatens the entire world of magic. They would have to combine their unique dragon - slaying abilities to defeat it, like Natsu's fire - based attacks with other slayers' powers.
A possible plotline is that Natsu's dragon form attracts the attention of dark wizards who want to use his power for evil. So he has to fight against them while also coming to terms with what it means to be a dragon. He may also have to deal with the physical and mental changes that come with this transformation, like different instincts and a new way of seeing the world.
One interesting plotline could be Lucy and Natsu going on a quest to find a lost dragon egg. Along the way, they face many challenges and their bond grows stronger. Another could be Natsu suddenly losing his dragon powers and Lucy having to find a way to get them back, which involves delving into some ancient magic lore.
Perhaps in the fanfiction, when Natsu turns into a dragon, he can communicate with other dragons in a way he couldn't before. This could lead to him uncovering secrets about his past and the origin of dragons in that fictional world. He might find out he has a special destiny related to the dragons.
One interesting plot twist could be that when Natsu turns into a dragon, he loses his memory of his human friends. This would create a lot of drama as his friends try to bring back the Natsu they know. Another could be that he turns into a different kind of dragon than expected, perhaps one with a very rare and powerful ability that attracts the wrong kind of attention from dark forces in the fanfiction world. And also, he might transform into a dragon at a crucial moment during a battle, not only surprising his enemies but also his allies, changing the whole dynamic of the fight.
One possible plotline could be Natsu developing unique magical abilities different from his canon ones due to being raised by another dragon. Maybe he has a different way of controlling fire or even some new elemental powers.
One interesting plotline could be Natsu discovering new dragon powers that are unique to him. This could lead to him having to learn how to control these powers and facing challenges within the Fairy Tail guild as others may be wary or envious of his new abilities.
One interesting plotline could be Natsu facing off against a powerful new dragon that has abilities he's never encountered before. This forces him to combine his skills as a multi - dragon slayer in unique ways.
Well, a cool plotline could be Naruto using her new female form to her advantage in missions. Maybe she can infiltrate places more easily as a girl. Also, there could be a plot where Naruto has to hide the fact that she was once a boy from some new characters she meets. This could lead to some really funny or tense situations as she tries to keep her secret while still being herself.