Obviously, Ciel and his twin are the main characters. Often, Sebastian, Ciel's butler, also plays an important role as he is involved in Ciel's life and would be affected by the presence of the twin.
Obviously, Ciel is the main character. He's the one usually in the diapers, and the story often revolves around his experiences, his emotions, and how others in the Black Butler world react to his situation.
It could be another powerful demon who sees the twin brother as a threat. Since he's new to the demon world, this more experienced demon might want to eliminate him.
Obviously, Ruby is one of the main characters. Her twin, who is often an original character created for the fanfiction, is also a main character. They usually face challenges together and their relationship is a central focus.
Elizabeth could also be a major character. When she finds out that Ciel has turned into a cat, she might be initially shocked but then becomes very attached to cat - Ciel. She could try to dress him up in cute cat outfits. And Grell could be involved too. Grell might mistake Ciel - cat for a normal cat and try to 'play' with him in his own rather dangerous and over - the - top way.
Ciel is surely the central figure. However, there could be other characters from the original source material that have also passed on and are in heaven. Additionally, there may be original characters created for the fanfic, such as a special angel who has a particular connection with Ciel. There might also be antagonists in the form of fallen angels or some sort of heavenly bureaucrats who oppose Ciel for some reason.
In addition to Ciel and his sister, there could be new characters created specifically for the fanfic. These new characters might be friends or foes of the sister. For example, a mysterious traveler who befriends the sister and helps her in her adventures, or a villain who is after something that the sister possesses.
Well, obviously the Twin Dragons themselves are the main characters. They usually have distinct personalities. One might be more impulsive and the other more cautious. There could also be side characters like their friends or allies. For example, a wise old wizard who gives them advice from time to time.
As we don't have more details about this fanfic, it's difficult to name the exact main characters. However, since it's called 'the twin dragons fanfic', the two dragons are likely to be the main focus. They could be joined by other important characters such as a wizard who helps or hinders them, or a princess who they are sworn to protect. Without reading it, it's all speculation.
The main characters are often the well - known Transformers from the 2007 movie, like Optimus Prime and Megatron. They are central to most of the stories as they are the leaders of their respective factions.
Often, there are characters who are sweet - lovers. Maybe a young girl or boy who has a special affinity for chocolate and is at the center of the story.