Rather than lemon fanfiction themes, the theme of family and loyalty is strong in 'Final Fantasy 13'. The relationships between the characters like Lightning and her sister Serah, and how they would do anything to protect each other. Also, the theme of hope in the face of a seemingly doomed world is prevalent. These are the kinds of themes that make for great fanfictions without going into inappropriate territory.
We should stay away from promoting lemon fanfiction themes. However, in regular 'Final Fantasy 13' fanfictions, a common theme is the redemption of characters. For example, how some of the antagonists might find a path to redemption. Another theme is the exploration of the technological aspects of Cocoon and how they interact with the magic in the world. These are much more interesting and appropriate topics.
If we try to look at it without the inappropriate 'lemon' aspect, regular Final Fantasy 7 fanfiction can have positive aspects. It can show great creativity in expanding the story and characters. But the 'lemon' part usually involves inappropriate content, so it's hard to say there are positive aspects directly related to that.
Some in the Final Fantasy community might not find 'final fantasy lemon fanfiction' acceptable. The official Final Fantasy games are aimed at a wide range of audiences, including younger players. Fanfiction with 'lemon' content goes against the family - friendly image of the franchise for many.
One of the most popular themes is the relationship between the main characters, like Cloud and Tifa or Cloud and Aerith. Many fanfictions explore their love stories in more depth. Another common theme is the fight against Sephiroth and his minions, as it was a central part of the original game.
One popular theme is the power exchange. Like a Naruto character learning Final Fantasy magic or a Final Fantasy character getting ninjutsu skills. Another is the crossover of the worlds, with characters traveling between the two.
One popular theme is forbidden love. Since the game has a set story, fanfiction writers often create scenarios where a gay relationship goes against the norms of the game world. Another theme is friendship evolving into love, like two male characters who start as comrades and then develop deeper feelings.
One common theme is Lulu's relationship with the other characters in Final Fantasy X. It could be her friendship with Yuna, or her more complex interactions with Wakka. Another theme is exploring Lulu's backstory in more depth, perhaps things that weren't fully covered in the game.
Another theme could be their relationship within their group or the politics of the supernatural world they inhabit. How they interact with other members, make alliances, and face off against enemies can make for great fanfiction. It's a more complex and engaging way to write about them compared to inappropriate themes.
Since 'lemon' fanfictions are not really in the mainstream due to their adult - nature, it's hard to say there are popular themes in this regard. But in general Sasuke - related fanfictions might have themes like his redemption, his power development. For Temari, themes could be about her role in her village. However, when it comes to their relationship in a non - 'lemon' way, themes could include mutual understanding and cooperation between different ninja clans.
Since 'lemon' fanfictions involve inappropriate content, I can't really promote or discuss their themes. But in general, non - inappropriate fanfiction themes about Harry and McGonagall could include things like McGonagall's influence on Harry's academic progress at Hogwarts.
Since Naruto and Demeter are from very different fictional universes, a common theme could be the clash of their different worlds. Maybe Demeter, with her connection to nature, tries to understand Naruto's shinobi world. Another theme could be a friendship that develops into something more, with the challenges that come from their different backgrounds.