Well, if Ciel watches the future in a Black Butler fanfiction, it depends on how the author writes it. One possibility is that he sees a future where his family is avenged but at a great cost, like losing his soul to Sebastian earlier than expected. Another is that he sees a future where his enemies have new allies and he has to find different ways to defeat them.
You could write a fanfic where the Black Butler characters react to different art forms. Suppose they visit an art museum in a modern setting. Sebastian, with his refined taste, would have in - depth critiques of the paintings and sculptures, while Ciel might be more drawn to the darker or more mysterious artworks. Or they could react to a live theater performance, with Ciel being amazed at the actors' skills and Sebastian observing the behind - the - scenes details like the stagecraft and the actors' emotions.
A group of rogue reapers. They don't follow the rules of the Death Gods and are causing chaos in the afterlife and the living world. Their actions start to affect Ciel's plans and he has to deal with them, which is difficult as they have unique powers related to death and time.
First, decide which characters from Black Butler you want to focus on. If you're writing a react fanfic, choose characters with distinct personalities like Sebastian and Ciel. Then, think of the situation or 'thing' they will be reacting to. It could be as simple as a new type of tea. Next, start with a strong opening that sets the scene. For example, 'Sebastian entered the room, a curious look on his face as he beheld the strange new brew.'
One interesting scenario could be the characters reacting to modern technology. For example, Sebastian might be both intrigued and a bit disdainful of a smartphone, finding it a curious yet overly complex device compared to the more straightforward tools of his own era. Ciel, on the other hand, could see it as a useful tool for gathering information quickly.
Grell is quite popular as well. His over - the - top personality and his unorthodox views make for some really entertaining reaction scenarios. He can go from being overly dramatic to having some surprisingly deep insights in fanfiction.
Perhaps Ciel will be shocked by what he sees in the future. He might see his own death or the destruction of his beloved manor. This could make him more desperate in his present actions, trying to change the future he witnessed.
One idea could be that Ciel has finally achieved his revenge, but now he finds himself lost without a purpose. He then discovers a new threat to the underworld that he feels compelled to fight against. This could involve new characters and a whole new set of mysteries.
Definitely not. The Black Butler series has a set of established themes such as the supernatural elements, the Victorian - era setting, and the complex character relationships. The idea of a 'leashed slave story' is completely foreign to the official canon and is likely a disturbing creation outside of the proper series. It would go against the overall tone and moral framework of the official work.