Friendship or an unlikely bond can be a major theme. Since they are from different universes, the fanfic may explore how they form a connection that goes beyond their initial differences. It could be based on mutual respect for each other's abilities or a shared goal.
It could be the one who manipulated Grayfia into betraying Naruto. Maybe it's a powerful and cunning villain from Naruto's world or even from another dimension. This antagonist could have a hidden agenda that involves getting rid of Naruto by using Grayfia.
One common theme could be the exploration of relationships. Since it's a fanfic, it might delve into the relationship between Grayfia and other characters in new and interesting ways. For example, how she interacts with different personalities within the fictional world.
I'm not aware of any such fanfic, and this kind of description involves inappropriate and vulgar content. Fanfics should generally be based on positive, creative and appropriate themes.
Another theme is power - up. As Naruto interacts with Grayfia and the other harem members, he often gains new powers or finds new ways to use his existing ones. This not only helps him in battles but also in his relationships as it makes him more appealing and respected in the harem dynamic.
One common theme could be crossovers. For example, if Grayfia is from a different series, there might be fanfictions that cross Naruto's world with Grayfia's origin world in an interesting way. The 'Lemon' aspect might bring in themes of romance or relationships, perhaps with some more adult - oriented undertones presented in a tasteful way in the context of Naruto's universe.
One popular 'grayfia naruto fanfic' might be those that explore her in unique crossover scenarios. For example, a fanfic could put Grayfia in the Naruto world and have her interact with the shinobi in interesting ways, like using her magic in battles against ninjutsu.
A great 'naruto grayfia fanfic' should have well - developed characters. Both Naruto and Grayfia need to be in - character, with their personalities and abilities accurately portrayed. For example, Naruto's never - give - up attitude and Grayfia's loyalty and power should be evident. Also, an interesting plot is crucial. It could be a story of them teaming up against a powerful foe or exploring a new world together.
In a 'grayfia betrayed naruto fanfic', perhaps Grayfia is tricked into believing Naruto is a threat to her world or someone she loves. So she decides to betray him. It might start with her subtly sabotaging Naruto's missions. As the story unfolds, Naruto discovers her betrayal and has to decide whether to forgive her or take revenge. And Grayfia may later realize her mistake but it's too late to easily fix things.
The themes in 'oc son of grayfia fanfic' often revolve around growth and acceptance. The oc son has to grow both in terms of his power and his understanding of the world. Acceptance comes in when he has to accept his role as Grayfia's son, which may come with certain responsibilities or expectations. There can also be themes of loyalty, as he may need to show loyalty to his family or to a particular group in the story.
Love against all odds is also a frequent theme. Given their different positions and the nature of the High School DxD world, their love might be seen as something that goes against the norm. So, many fanfics will center around how they fight for their love in the face of various obstacles, whether it's social hierarchies or threats from other characters. It makes for a very engaging read as the story unfolds.