Another aspect could be the characters' relationships with real - world people. Ciel could form an unlikely friendship with a modern - day detective. They would exchange knowledge, with Ciel sharing his insights from solving mysteries in his world and the detective teaching Ciel about modern - day forensics. This could lead to a series of adventures as they work together to solve crimes in the real world.
Sebastian, being a demon, would have an easier time adapting in some ways. He could use his powers subtly. For instance, his speed could be used to quickly move around in a busy city without being noticed. He'd also be intrigued by modern cuisine and might experiment with new ingredients while still maintaining his high - class cooking standards.
Ciel would probably have a hard time adjusting. In his world, he has a certain status and power. In the real world, he's just a young boy. He'd have to deal with going to school, which would be very different from his private tutoring in the Black Butler universe. And he might be fascinated by modern medicine as it's so different from what he's used to.
Maybe a plot where Sebastian and Ciel are attending a high - school in the real world. Ciel is the new student who is a bit of an enigma, and Sebastian is his butler who also doubles as a teacher at the school. There could be a mystery surrounding a series of strange events at the school, like students disappearing. Sebastian and Ciel use their skills from their original world to investigate. Ciel uses his intelligence to piece together clues, and Sebastian uses his supernatural abilities discreetly to protect Ciel and solve the mystery.
Another plot could involve a real - world detective who stumbles upon the existence of Ciel and Sebastian. The detective is initially skeptical but as he witnesses their abilities, he becomes involved in their world. This could lead to a series of adventures where the detective has to learn to work with the duo from the Black Butler universe to solve crimes that are somehow related to the dark secrets of the Phantomhive family in the real - world setting.
Well, Sebastian would probably be a very sophisticated butler in a high - class household. He'd be able to handle all the tasks with ease and charm everyone with his manners. Ciel might be a young entrepreneur or something, using his wits to succeed in the business world.
The demons in 'Black Butler' would have to be more discreet in the real world. So, Sebastian's actions would be more low - key. And Ciel's revenge plot might be more about using legal means rather than the more extreme measures in the original story.
I think Grell would be really interesting. In the real world, Grell's flamboyant and over - the - top personality would create a lot of chaos. He could be a fashion designer or something similar, still with his love for the color red and his chainsaw. His interactions with Sebastian would be hilarious, as Sebastian would be constantly trying to keep him in line while also dealing with the real - world problems.
One idea could be creating a story where a new character arrives at the Phantomhive manor with a special power that Ciel is initially suspicious of but later realizes can be useful in his battles against his enemies. For example, the power to communicate with the dead, which could provide valuable information in their investigations.