A fanfiction could explore what would happen if the Black Knights discovered a new Geass power within their ranks. This could lead to internal power struggles as well as new strategies in their fight against the Britannian Empire. They might have to decide how to use this new power, whether for good or for their own gain, and how it would affect their relationships with each other.
You can try fanfiction websites like FanFiction.net or Archive of Our Own. They have a wide variety of Code Geass fanfictions, including those related to the Rise of the Black Knights. Just search for 'Code Geass Rise of the Black Knights' in the search bar, and you'll get a list of relevant stories.
One common theme is loyalty. Since the Black Knights are a group, many fanfictions explore the loyalty among its members, and how they deal with betrayals or doubts within the group. Another theme is the fight for justice. They are rebels, after all, and fanfictions often delve into their motives and the different ways they pursue justice in the Code Geass universe.
I'm not sure specifically about 'Code Geass Black Knights' fanfiction directly related to suicide. Fanfiction can cover a wide range of themes, but this is a rather dark and serious one. It might exist in some corners of the fanfiction community, but it's not a common or widely promoted type of story due to its disturbing nature.
One possible impact could be that it may make some readers uncomfortable. Given that 'Code Geass' has a wide fan base that includes younger audiences, such a topic can be disturbing. It might also shift the perception of the 'Black Knights' in a very negative way, as they are usually seen as a force for change and justice in the series.
One possible reason could be a power struggle within the Black Knights. Maybe some members grew envious of Lelouch's leadership and power, seeing him as too controlling. Another reason might be external influence. If an enemy was able to infiltrate the Black Knights and spread false information or make false promises, it could lead to a split. Also, ideological differences could play a part. As the group grew, some members might have started to have different views on how to achieve their goals, leading to a breakdown in unity.
It's important because the Black Knights are a symbol of resistance in the Code Geass universe. Their loyalty represents the hope of the people. If they were to betray, it would mean the loss of that hope. So in fanfiction, maintaining this non - betrayal concept keeps the essence of their character intact.
You can start by looking on fanfiction websites like FanFiction.net or Archive of Our Own. They usually have a wide variety of Code Geass Black Knights fanfictions. Just search for 'Code Geass Black Knights' in their search bars, and you'll get a bunch of results. You can then sort them by popularity, rating, or recency to find the ones that might interest you.
One possible scenario could be that the Black Knights face an extremely powerful new enemy that tries to break their unity, but their unwavering loyalty to each other prevails. They might come up with new and innovative battle strategies to combat this threat.
It could be that the 'Rise of the Dark Lord' is a consequence of some event that went differently in the fanfiction compared to the original series. For instance, if Lelouch made different choices regarding the use of his Geass. Maybe he became corrupted by the power and started to rule with an iron fist, thus becoming the 'Dark Lord'. This would change the relationships he had with his friends and allies, like Suzaku. And the story would be about the chaos and destruction that follows as he ascends to this dark position, and the efforts of those who oppose him to bring him down.