There are many other great aspects of Nagisa's character that can be explored in proper fan - made works, such as her growth, her relationships in a non - sexual way, but not in the context of sexual fanfiction.
One possible fanfiction could be about Nagisa, as a girl, having to deal with the unique challenges in the Assassination Classroom. Maybe she uses her newfound femininity to her advantage in different assassination attempts. For example, she could play on the stereotypes that others might have of a girl being less of a threat, only to surprise her opponents.
In a fanfiction where Nagisa turns into a girl, it could be part of a wish - fulfillment scenario. Nagisa secretly wished to experience life as a girl for a day, and some supernatural being grants that wish. As a girl, Nagisa has to navigate through daily life, school, and social situations. There could be humorous moments when Nagisa tries to act like a girl but still has some of the old habits from being a boy, like being too rough during sports in a girl's body.
The plot could center around Nagisa's relationships with the female students in the class. Since she has now become a girl, she might form a closer bond with them. They could start a girl - only club or group within the class where they share secrets and train together. However, this could also lead to some jealousy or conflict from the male students. Nagisa would then have to navigate through these relationship issues while still focusing on the main goal of assassinating Korosensei.
Nagisa's best friend might be really surprised at first. But then, being a true friend, would support Nagisa through this strange change. They would probably help Nagisa with things like choosing girl - appropriate clothes or dealing with any mean comments from other students.
One idea could be Nagisa as a girl joining an all - female sports team and facing challenges from rivals. She could struggle at first but then prove herself through hard work.
One possible fanfic could be about Nagisa, as a girl, having unique interactions with the other students in Class 3 - E. Maybe she forms a special bond with Karma that is different from the original story due to her changed gender. She could use her skills in a new way, for example, her stealth might be enhanced by her newfound femininity, as she could blend in more easily in certain situations. Another aspect could be how she deals with the challenges of being a girl assassin in training, facing different expectations from her classmates and teacher.
Well, a possible plot could be that Nagisa, as a girl, discovers new powers or abilities that are related to her femininity. Maybe she has a special intuition that helps the class in their assassination attempts. The story could also focus on her love life. She might develop feelings for a new character or perhaps Karma in a different way than in the original story. There could be a lot of drama as she tries to balance her feelings with her duties as an assassin in training.