What are some interesting plot ideas in 'Black Butler Ciel x Reader' fanfiction?

One idea could be that Claude discovers a hidden power within Ciel that even Ciel himself is unaware of. This power could be related to Ciel's past or family heritage. Another plot could be that Claude has to protect Ciel from a new and powerful enemy that is specifically targeting Ciel for some unknown reason. Maybe this enemy has a connection to Claude's past as well.

One idea could be that fem Ciel has to attend a grand ball and Sebastian helps her get ready in a very intimate way, like choosing the perfect dress and doing her hair, while they share some flirty banter. Another could be that fem Ciel gets into trouble with a rival noble and Sebastian uses his demonic powers in a very creative way to protect her, all while their relationship deepens. And perhaps a plot where fem Ciel discovers a secret about Sebastian's past that makes her see him in a new light and changes the dynamic of their relationship.

For an interesting plot, imagine that Alois and Ciel find themselves in a parallel world where their roles are reversed. Alois is now the more proper and reserved one while Ciel is the more flamboyant and unpredictable. This role - reversal forces them to see things from the other's perspective. They have to adapt to this new world and each other. Maybe in this world, there is a prophecy that only they can fulfill together. As they strive to do so, their relationship evolves. They might start off hating the change but gradually come to accept and rely on each other more than ever.

One idea could be Female Ciel trying to navigate the underworld of the Black Butler universe while facing discrimination for being a female in a male - dominated world. She might have to prove herself even more than her male counterpart did.

One idea could be Ciel exploring his new demonic powers. He might start to see the world in a completely different way, with his values shifting as he is no longer bound by human limitations. For example, he could use his powers to seek revenge in a more extreme way than he could as a human.

One interesting plot idea could be a time - travel scenario. Sebastian and Ciel are sent back in time to a period in the Phantomhive family's history that is shrouded in mystery. They have to navigate the past, deal with their ancestors, and also face the fact that their actions in the past could change the present they came from. Another idea is a role - reversal. Ciel becomes the demon and Sebastian the human servant, which would completely turn their relationship dynamics on its head and lead to all sorts of comical and also thought - provoking situations. A third plot could be a crossover with another popular anime world, like they end up in the world of Naruto and have to adapt to the ninja way while still maintaining their own goals and relationship.

One idea could be that the reader is a new undertaker's apprentice. They start off being clumsy and Undertaker finds it both amusing and endearing. As time passes, a deep bond forms between them, and they face various supernatural challenges together in the world of Black Butler.

Perhaps a story where Elizabeth and Ciel time - travel back to a period before all the tragedy in Ciel's life occurred. Elizabeth could then try to prevent the events that led to Ciel's current state. This would involve her getting to know a more innocent Ciel and also dealing with the consequences of changing the past, such as how it might affect their relationship in the present.

A plot could revolve around Female Ciel being kidnapped by a rival family who wants to use her to gain power. Sebastian then has to use all his skills to rescue her without breaking the terms of their contract. During her captivity, Female Ciel could learn more about the true nature of her enemies and find a way to turn the situation to her advantage. Or perhaps there is a ball where Female Ciel is expected to find a suitor. But she has no intention of getting married as it would interfere with her goals. Sebastian has to help her fend off unwanted suitors while also dealing with the demons and other dark forces that lurk in the shadows of the ballroom.

One idea could be a fanfiction where Ciel and the demon, instead of their usual master - servant relationship, become allies in a different realm. They could be on a quest to save a parallel world that is being threatened by a powerful dark force. Another idea is a story where the demon has to protect Ciel from a group of rogue demons who see Ciel as a valuable asset due to his connection with the underworld. Maybe in this fanfiction, Ciel discovers a new power within himself that the demon has to help him control.