One possible plot could be that Luffy, now as a girl, has to navigate the pirate world in a different way. Maybe the crew has to deal with different reactions from other pirates and people they encounter. Some might underestimate her because she's a girl, but Luffy's strong will remains the same, and she shows everyone that gender doesn't matter when it comes to being a great pirate.
Well, perhaps the plot could involve Luffy having to navigate a world where he is suddenly a girl. He might face challenges in how his friends perceive him now. Maybe he has to deal with different social expectations while still maintaining his goal of finding the One Piece. For example, some of his male friends might be overly protective or act a bit differently around him, and he has to figure out how to handle those new dynamics all while being in a female body.
The Straw Hat crew's reaction would be quite diverse. Usopp might make some jokes at first about Luffy's new look but would support her all the same. Robin would be very observant and might notice how Luffy's new form could change the crew's dynamics. Franky would be his usual self, shouting some over - the - top phrases about how cool 'female - Luffy' looks. Brook would probably make some bone - related puns about Luffy's new femininity while still respecting her as the captain. Overall, they would all adapt in their own ways and continue to follow Luffy on their adventures.
His personality would stay largely the same in terms of his goals and values. He still wants to be the Pirate King. But in social situations, he could be more cautious. As a girl, he might face different types of challenges when interacting with other pirates or people in general. He might have to rely more on his wits rather than just brute force in some situations, which could be a new aspect of his personality development in this fanfic.
One possible storyline could be that Ivankov, with his unique powers, decides to turn Crocodile into a girl as a form of punishment or to teach him a lesson. Crocodile, now in a female form, has to navigate a world that treats him differently. He might struggle with his new identity, having been a powerful and feared male pirate before. This could lead to many comical situations as he tries to adapt, like dealing with different clothing styles and social expectations.
Crocodile's character would likely become more in - touch with emotions. As a male, he was often portrayed as cold and calculating. But as a girl, she might be more likely to show vulnerability. For example, she could be more empathetic towards others, especially if she experiences discrimination based on her new gender.
The Marines could still be antagonists. They might view Luffy's transformation as a sign of weakness or an opportunity to capture her more easily. They could underestimate her because she is now a girl, but of course, they would be wrong.
Perhaps there could be a plot where Luffy, as a girl, has to use different strategies in battles. Since the opponents might underestimate a female opponent, Luffy could use this to her advantage and surprise them with her strength. This would also show a different side of Luffy's combat intelligence.
In a fanfiction where Luffy turns into a girl, the story could take an interesting turn. Luffy's dreams of becoming the Pirate King wouldn't change, but the way he approaches it might. As a girl, he could use his charm to get out of some tricky situations. For example, when dealing with some of the more traditional pirates or marines who might underestimate a girl. Also, the Straw Hat crew's dynamic would shift. Zoro might be more protective, not that he isn't already, but in a different way. And Chopper would be super curious about the sudden change and would constantly be checking if there are any medical reasons for it, even though it's a magical fanfiction change.
His core personality might not change much. Luffy is still likely to be as carefree and adventurous as ever. However, he might become a bit more sensitive to certain things, like how people treat girls. He'd still be fearless in the face of danger, but could use his new form to his advantage in different ways, like when dealing with female characters who might be more likely to trust a girl.