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.
In addition to the main characters, characters like Finny, the gardener with his superhuman strength, can be interesting to feature. Fanfiction can explore his backstory more deeply, like how he got his powers and how he copes with being different. Bardroy, the chef, is also a character that can add a lot to a story. His military past and his rather unique cooking skills (or lack thereof) can be a source of great stories in fanfiction.
Ruby is often a popular choice. Her naivete and wide - eyed wonder make her reactions interesting. Whether it's reacting to a new place or a strange object, she has a charm that draws readers in.
Ciel is definitely one of the most popular. His complex personality and his tragic backstory make him a great focus for fanfiction. Writers can explore his inner thoughts and feelings more deeply. Sebastian is also very popular. His demonic nature and his loyalty (in a rather twisted way) to Ciel are fascinating aspects to write about. Grell is another popular character. His flamboyant and somewhat deranged personality offers a lot of room for creativity in fanfiction.
Jon Snow is often a popular choice. His noble and brooding nature makes for interesting reactions in fanfiction. Fans like to imagine how he'd respond to various out - of - character situations.
Midoriya is very popular. His growth and development throughout the series make him an interesting character to react to various situations. Fans like to write about him reacting to new challenges or revelations, as he is the main protagonist and his reactions can shape the overall mood of the fanfiction.
William T. Spears is also quite popular. His strict and no - nonsense attitude provides a great contrast to other more chaotic characters, and fanfiction often plays with his interactions with other reapers or the main Black Butler characters.
Croaker is often a popular choice. He's the main narrator in the original work and has a lot of depth to his character. His knowledge of medicine and his role as the chronicler of the company's events make him an interesting character to build on in fanfiction. Another popular character is Raven. His mysterious past and his skills as a warrior draw a lot of attention. People like to explore his backstory more or put him in different situations that test his abilities. Lady is also a great character to feature. Her power and her complex relationship with the company are things that can be delved into further in fanfiction.
Ciel Phantomhive is often paired with the twins in fanfiction. Since he is a central character in the Black Butler series, writers like to explore different dynamics between him and the twins, such as a power struggle or a forced alliance.
Sebastian is often very popular. His demonic charm and loyalty to Ciel, despite his ulterior motives, make him a fascinating character to write about. Fanfiction writers can explore his internal struggles between his demonic nature and his growing attachment to Ciel.
Richtofen is often a popular choice. His complex personality and his role in the Zombies storyline make him an interesting character to explore further in fanfiction. Writers can delve into his motives and his relationship with the other characters more deeply.