Well, one big difference in her character development is in the area of emotions. Female Natsu might be more in touch with her emotions and express them more openly. This could lead to deeper connections with other characters but also make her more vulnerable in some situations. For instance, she might be more affected by the loss of a guildmate. In terms of her growth as a mage, she may be more interested in exploring the history and lore of magic, which was not as much of a priority for male Natsu. This newfound interest could open up different storylines for her, such as discovering ancient magic spells or artifacts that were previously overlooked by male Natsu.
Her character development can be different in terms of relationships. As a female, she might be more empathetic towards other female characters in the guild, which could lead to different friendships. For example, she could form a closer bond with Lucy in a more sisterly way. In terms of her magical development, she may approach it with a different mindset. Maybe she's more cautious or strategic compared to the impulsive male Natsu. This could lead to her learning spells in a different order or mastering them in a different way.
Their relationship could develop differently if Natsu didn't initially see Zeref as an enemy. Instead of the typical animosity, Natsu could approach Zeref with curiosity. Maybe he wants to understand why Zeref created him and what his purpose really is. This could lead to a more cooperative relationship from the start.
Often, Natsu becomes more confident. With the Dragon Force, he realizes his greater potential, which boosts his self - assurance.
Natsu's character development in this fanfiction might involve him becoming more responsible. With his end form, he has greater power and with that comes the need to use it wisely. He could start to think more about the consequences of his actions. For example, he might not rush into battles as blindly as he used to. Also, his emotional growth could be a part of it. He could become more in tune with his feelings towards his friends, especially Lucy. His loyalty to the guild could also deepen as he realizes his new form can be a great asset to protect Fairy Tail.
Natsu would likely become more responsible. Taking care of a baby is no easy feat, and he'd have to learn things like being gentle and patient, which are not his usual strong suits. This would be a big step in his character growth.
Natsu would likely become more solemn. He was always the fun - loving, energetic one. But with Fairy Tail gone, he'd have to grow up fast. He might become more calculating in his battles, instead of just charging in like he used to.
In many fanfictions, Natsu's character develops by becoming more responsible. As the Red Dragon Emperor, he has greater power and with it comes more responsibility. He starts to think more about the consequences of his actions and how they affect not only his friends but also the world around him.
One common plot twist could be that as a female Natsu, she discovers new magical abilities that male Natsu didn't have. For example, she might be able to control certain elements in a different way. Another plot twist could be in the relationships. Maybe she has a different kind of bond with Gray. Instead of the competitive male - male relationship, it could turn into a more complex, perhaps even a romantic tension. Also, she could face challenges within the Fairy Tail guild that are specific to being a female in a male - dominated world of mages. The guild members might have different expectations of her, and she has to break through those stereotypes to prove herself.
Natsu could develop a sense of guilt. If he lost comrades during the war, he might blame himself for not being strong enough. This guilt could either drive him to become stronger or make him more withdrawn. He may also start to question his own beliefs. For instance, if he had to do some morally ambiguous things during the war to win, he'll have to grapple with the consequences of those actions.
I'm not sure who exactly Natsu is just from 'natsu reads fanfiction'. It could be a normal person who just enjoys reading fan - made stories. Maybe it's a nickname for someone within a particular fan community.
As they travel, their bond deepens. They start to rely on each other more. Natsu becomes more protective of Lucy, and Lucy begins to understand Natsu's impulsive nature better.