Well, a major theme is the clash of different worlds. Code Geass has its own political and power - based world, while High School DxD is more about the supernatural world of devils, angels, etc. In the fanfics, you see how these two different worlds collide. For example, the strict military and strategic world of Code Geass meeting the more chaotic and free - flowing world of High School DxD. And there's also the theme of morality. The actions that are considered moral or immoral in each series are put to the test when the two are combined in fanfics. For instance, using the Geass power in the DxD world might be seen in different ways depending on the different moral compasses of the characters.
One common theme is the idea of identity. In Code Geass, Lelouch has to hide his identity as Zero while in High School DxD, the main character has to deal with his new identity as a devil or whatever supernatural being he becomes. In the fanfics, this is often explored further, like when a character with a Geass has to hide it while also dealing with their new identity in the DxD world. Also, loyalty is a theme. In both series, there are groups and factions, and in fanfics, characters have to decide where their loyalties lie when these two universes collide.
Love and loyalty also pop up a lot. Highschool DxD has a lot of elements related to love and loyalty within its harem - like setting. When combined with Code Geass, fanfics may show how characters develop new relationships or test their existing loyalties. For instance, a character from Code Geass might find themselves in a situation where they have to choose between their loyalty to their original cause and the new relationships they form in the world of Highschool DxD.
Sure. There's a fanfic named 'Geass - Powered Devils' that's quite good. In this fanfic, the elements of Code Geass are seamlessly integrated into the High School DxD universe. The story follows a character who has a Geass and gets involved with the various factions in the DxD world, like the devils, angels, and fallen angels. It's a really exciting read as it explores how the Geass ability can change the power dynamics in this already complex world.
One common theme is Gino's loyalty. Many fanfics explore how his loyalty to the Britannian Empire or to certain characters affects his decisions. For example, how he balances his loyalty to the empire with his personal beliefs.
One common theme could be power struggles. Since Code Geass is about a world with complex power dynamics, Marrybell OC fanfics might explore how an original character fits into that, whether they are trying to gain power, resist it, or something in between.
Well, often the theme of isolation is present. Lelouch was a very lonely character in many ways. In a suicide fanfic, this isolation could be exacerbated. He might feel that no one truly understands him or his motives. It could also explore the theme of power and its consequences. Lelouch had great power with his Geass, and his suicide could be a way of escaping the burden of that power. Maybe he realizes that the power has corrupted him in some ways or led to too much destruction, and death is his way out. And then there's the theme of legacy. His suicide could be seen as a way to leave a certain kind of legacy, whether it's a martyr - like one or a cautionary tale about the pursuit of power.
One common theme is power acquisition. Since 'Code Geass' is about special powers, self - insert characters often gain a unique Geass or some other extraordinary ability and then have to figure out how to use it in the complex world of the series.
One more theme that pops up a lot is the exploration of 'what - if' scenarios. Fanfic writers like to play with the idea of what would have happened if certain events in the series had been different regarding Lelouch and Shirley. For instance, what if Shirley had found out about Lelouch's true identity earlier? This leads to different relationship dynamics and storylines in the fanfics, which is really interesting to read about.
One common theme is the exploration of gender roles. Since Lelouch is female in these fanfics, it often challenges the traditional male - dominated power dynamics in the original Code Geass world. For instance, a female Lelouch might have to use different strategies to gain power and respect.
One common theme is power and its corrupting influence. The male OC often has to deal with the allure and danger of power in the Code Geass world. Another theme is identity. Since the OC is original, there's a focus on how he discovers and defines himself within the context of the existing story.