Well, a lot of 'cat black butler fanfiction' has themes related to the supernatural. Since Black Butler already has a lot of supernatural elements, adding a cat with its own strange powers fits right in. There are also themes of friendship. The cat could form an unlikely friendship with a character in the story. Sometimes, there are themes of transformation too, where the cat might transform into something else, which adds an exciting element to the plot.
One common theme is mystery. The cat often brings an element of mystery to the story. Another is loyalty, as the cat might be fiercely loyal to a particular character.
The theme of redemption is also quite common. Since Grell has done some rather dark things in the 'Black Butler' series, many fanfictions explore whether he can find redemption. Some stories show him trying to make amends for his past actions, either through helping others or by changing his ways. And of course, the theme of friendship or camaraderie among the reapers, especially with Grell, is often explored. We see how he interacts with other reapers and how those relationships develop or deteriorate in different fanfictions.
One common theme is obedience. Since discipline often implies following rules or orders, many fanfictions explore how the characters in Black Butler, like the servants in the Phantomhive manor, learn to be obedient. For example, they might face consequences if they don't follow Sebastian's instructions.
One common theme is the idea of rebirth or transformation into a baby form. This often leads to a change in the power dynamics between characters. For instance, a powerful character like Ciel becoming a baby makes him vulnerable, and other characters have to step up to protect him.
Another theme is sacrifice. In many fanfictions, the characters are willing to sacrifice a great deal for their love. This could be their status, their safety, or even their own lives. It adds a sense of drama and intensity to the romantic story. For instance, a character might risk everything to be with the one they love in a world full of danger and mystery.
Character growth is also a common theme. Characters from both series are put in new situations. Naruto might have to adapt to the strict social hierarchies in the Black Butler world, and characters from Black Butler might learn from Naruto's values of friendship and determination. This allows for a lot of character development and makes the fanfictions more engaging as we see familiar characters evolving in new ways.
Another theme is his past as a soldier. Fanfictions like to expand on his military experiences, like how he dealt with the trauma of war. It could be about him having nightmares and how he overcomes them while serving the Phantomhives.
One common theme is the idea of forbidden love. Given the nature of the 'Black Butler' world with its hierarchies and secrets, many fanfictions explore relationships that are not supposed to happen. For example, a relationship between a servant and a noble.
One common theme is the struggle with identity. Given the Victorian - era backdrop of Black Butler, characters often struggle with their feelings in a society that may not be accepting. Another theme is loyalty. Their relationship, whether as master - servant or as lovers, is often tested, and loyalty plays a big part.
One common theme is Soma's growth. Fanfictions often explore how he matures from a carefree prince into a more responsible and capable character. Another theme is his relationships, like his friendship with Ciel or his interactions with the other servants. And adventure is also a big theme, as Soma gets involved in various exciting escapades in the fanfictions.
One common theme is friendship. Finny's relationships with the other servants, like Sebastian and Mey - Rin, are often explored. Another theme is self - discovery. Finny is a character with a lot of potential, and many fanfictions focus on him finding out more about himself.