It might be a key line that showcases Lelouch's character development or a statement that has consequences for other characters. It could be used to build suspense and keep readers engaged.
They often show his internal conflict between his goals and his morality. Lelouch wants to change the world, but the methods he uses are often morally ambiguous. In a suicide fanfic, this struggle might reach a breaking point. He could be constantly thinking about all the wrongs he has committed in the name of the greater good. For example, he might be haunted by the memories of the people he has killed or manipulated. His Geass power also adds to his inner struggle. He may feel that the power has made him into a monster, and he can't live with that anymore, so he contemplates suicide as a way to end his inner turmoil.
In many light novels, strange phrases like 'do ein and zwei die' can have multiple interpretations. If 'ein' and 'zwei' are names, their deaths might be a crucial plot point. Maybe they are part of a group, and their deaths trigger certain events in the story. However, it could also be a symbolic way of representing the end of the first two phases or elements in the novel's overall structure.
The significance could be in exploring different perspectives. In such a novel, the 'he said' and'she said' format might be used to show the contrast between male and female viewpoints, or different characters' takes on events, which can add depth and complexity to the story.
There are 'lelouch fanfic' stories that rewrite the ending. Maybe in these fanfics, Lelouch doesn't die at the end. Instead, he manages to find a way to create a new world order without sacrificing himself. Some fanfics also focus on the interactions between Lelouch and the other characters from different perspectives, such as his relationship with Suzaku as if they had made different choices earlier in the story.
Often, they explore the relationship between lelouch and cc in more depth. It might show their interactions in different scenarios.
Another aspect is the psychological aspect. Since both characters are complex, fanfics usually dig into their minds. They might show how Schneizel's calm and calculating nature contrasts with Lelouch's more passionate and impulsive side. This contrast can create a lot of interesting scenarios and internal conflicts within the story.
Since the idea involves such a disturbing concept as rape, it should not be promoted. Fanfics are supposed to be creative works within the boundaries of legality and morality. There's no value in exploring the details of this kind of 'fanfic'.
One common theme is the exploration of their complex relationship. They have a deep connection in the original series, and fanfics often expand on it, like delving into their trust issues. Another theme is the power dynamics between them, as CC has her own powers and Lelouch has his Geass.