Another theme could be the power dynamics between them. Zeref is a very powerful character, and Roubaul also has his own abilities. Fanfics might explore how a female version of Zeref would interact with Roubaul in terms of power, whether it's cooperation, competition, or something in between.
Some dedicated Fairy Tail fan communities also share fanfics. You can join forums or groups related to the series. Members might recommend their favorite Female Zeref Roubaul fanfics or even write their own. It's a great way to discover unique and interesting stories.
One common theme is redemption. Many fanfictions explore the idea of Zeref being redeemed through his interaction with the female character. For example, the female might show him kindness or love that he has never experienced before, leading him to question his evil ways.
One common theme is power struggle. Since Zeref is a very powerful character, when he crosses over into other universes, there is often a struggle for power with the existing powerful entities in those worlds. For example, in a crossover with a superhero universe, Zeref's dark magic might clash with the superpowers of the heroes.
One common theme is the power struggle. Zeref is extremely powerful, and Lucy has her own unique powers. Their relationship often involves how they deal with the power differential. For example, in some fanfictions, Lucy has to learn to hold her own against Zeref's overwhelming power.
Common themes include the power of love to change a person. Zeref, with his dark past and powers, could be changed by Lucy's love. Also, there's the exploration of destiny. Some fanfictions might suggest that they are fated to be together despite all the odds. Additionally, the theme of self - discovery can be present. Through their relationship, both Zeref and Lucy might learn more about themselves and their true desires.
A lot of these fanfictions also have a theme of redemption. Fem Zeref might be portrayed as a character seeking redemption for past actions, and Natsu could be the catalyst for that change. It's a way to give a new perspective to Zeref's character. Additionally, themes of friendship or unrequited love are also common. The relationship between Natsu and Fem Zeref can be explored in a platonic or romantic way, and often there are misunderstandings and moments of self - discovery related to these feelings.
The exploration of different worlds is also a common theme. Naruto is from the Hidden Leaf Village in his ninja world, and Zeref is from the Fairy Tail world. Fanfictions might have them travel between these worlds, comparing and contrasting the cultures, magic systems, and social structures. This not only adds an element of adventure but also helps in understanding how their characters would react in different environments. For instance, Naruto might be shocked by the prevalence of magic in Zeref's world, while Zeref could be intrigued by the ninja way of life.
Typically, it might explore a different side of the characters. Maybe it shows Zeref from a female perspective, which could bring new interpretations of his powers and motives. And for Nirvana, it could add new dimensions to the story.
One common theme could be power and its consequences. Zeref in Fairy Tail has a complex relationship with power, and 'Familiar of Zero' also has elements of power struggles. Another theme might be the exploration of different magic types. Since both series have their own magic systems, fanfiction could blend and compare them. For example, the dark magic Zeref wields and the magic used in 'Familiar of Zero' could be contrasted or combined.
One common theme is the exploration of their shared past. Since they are brothers in these fanfictions, writers often dig into what their childhood might have been like.