Well, Kallen is likely to be one of the main characters interacting with Lelouch. She was an important part of the original story, and in the fanfic, she could be helping Lelouch in his new endeavors, or perhaps she has some doubts about his return. Also, Nunally might play a role. If she discovers Lelouch is alive, it would be a very emotional reunion and they would have to re - establish their relationship.
C.C. is often a main character that interacts with Lelouch. Their relationship is complex and in the fanfic, they might continue to explore their connection, whether it's about the Geass or their personal feelings. Suzaku also could be a key character. He might have to come to terms with Lelouch being alive and they could either become allies again or have a more strained relationship.
In these fanfics, Jeremiah could be an important character interacting with Lelouch. Since he had his own arc in the original series, in the fanfic he could be one of the few people who knew about Lelouch's survival plan all along. He might be providing support or even acting as a bodyguard for Lelouch. And then there's also Rolo. Even though he died in the original, in the fanfic world, his memories or some form of him could be brought back to interact with Lelouch in a very unique way.
The main character is Lelouch Lamperouge. He is the one who drives the story forward with his intelligence and the power of Geass. Another important character is C.C. She has a special connection with Lelouch through the Geass power. Nunnally, Lelouch's sister, is also crucial as Lelouch's actions are often motivated by his love for her. And there's Kallen Stadtfeld, who has her own feelings for Lelouch and is an important part of the story's events.
One interesting plotline could be Lelouch having to deal with the aftermath of his 'death' being faked. Maybe he has to secretly guide the new world order he created without revealing his true identity. Another could be his relationships with the other characters, like how he reconnects with C.C. in a new and different way.
I'm not sure specifically as it's a fanfic. It could be about Lelouch from Code Geass in some sort of capsule - related situation. Maybe it's a unique take on his character, like he's trapped in a capsule and has to figure out a way to escape or use his Geass powers in a confined space. It could also involve some new plotlines with other characters coming to his aid or trying to stop him.
One great fanfic in this category is 'The Geass Exchange'. It explores an alternate scenario where Lelouch gives his Geass to a different character, Suzaku. This creates a whole new dynamic as Suzaku, with his own set of beliefs and moral code, has to grapple with the power of Geass. The story delves deep into how the Geass affects his relationships, not just with Lelouch, but also with other characters in the Code Geass universe like Euphemia. It's a really interesting take on the concept of Geass transfer and how it can change the course of events.
The themes of sacrifice and redemption are quite common. Rolo, in particular, has actions that could be seen as in need of redemption, and Lelouch's own goals often require sacrifice. Fanfics may focus on how Rolo tries to redeem himself in Lelouch's eyes or how Lelouch sacrifices for Rolo. Additionally, the theme of power and control is present. Lelouch has the Geass power, and how he uses it in relation to Rolo and their relationship can be a central theme in fanfics.
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.
The power dynamics. When Lelouch gives someone Geass, it completely changes the balance of power. For example, if he gives it to a character who was previously powerless, like a civilian, that character suddenly has the ability to influence others in a major way. This can lead to all kinds of new plotlines and character interactions.
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 possible plot in this fanfic could be the emergence of new leaders who try to emulate or completely oppose Lelouch's ideology. His death could be the catalyst for a new wave of change or a regression back to the old ways. The fanfic could also explore the idea of his legacy, whether he is remembered as a hero or a tyrant, and how that perception changes over time.
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.