Oz Vessalius is a great character to feature. His complex backstory, including his connection to the Abyss, gives a lot of room for exploration in a fanfic. Another good one is Alice. Her brash and often unpredictable nature can add a lot of interesting twists to a story. Also, Gilbert is a character full of loyalty and internal conflict, which can be used to create engaging storylines.
Definitely Xerxes Break. His mysterious past and his rather cynical view of the world make him a very interesting character for a fanfic. You can really dig into his motives and his relationship with other characters, like Sharon. Sharon herself is also a great choice. As a young and powerful member of Pandora, she has her own set of goals and relationships that can be explored in a fanfic. And let's not forget about Vincent Nightray. His dual nature and his complicated relationship with his brother Gilbert can be the basis for some really intense fanfic storylines.
Riku is also a popular character to feature. His complex past and his struggle between light and dark make for interesting storylines. You could write about his continued efforts to atone for his past mistakes and his role in protecting the different worlds.
Oz Vessalius is one of the main characters. He is a young nobleman with a mysterious past. Then there's Alice, a powerful being. And Gilbert, who is loyal to Oz.
It has a unique and captivating storyline. The characters are well-developed and the art style is amazing.
Since I haven't read the Pandora Hearts Cacus Race Novel, I can't say for sure. However, in the Pandora Hearts series, there are characters like Alice who is quite significant. In this novel about the Cacus Race, there could be characters directly related to that race who play the main roles, perhaps a Cacus Race leader or a young Cacus who has some special destiny within the story.
Xander is a great character to feature. He's always full of energy and getting into fun adventures, which can make for an exciting story. Also, Emma, as she's often the voice of reason among the campers and can bring a sense of stability to the plot. And Lou, the counselor, is another good choice as she has to deal with all the camper's antics.
Erina could also be great. Her refined palate and high standards add a layer of complexity. A fanfic could explore her journey of trying new and unorthodox cooking styles while still maintaining her elegance and grace in the kitchen.
Oliver Queen is an obvious choice. He has such a complex backstory with his time on the island, his return to Starling City, and his evolution into the Green Arrow. His relationships with other characters like Diggle, Felicity, and Laurel also offer a lot of material for a fanfic.
First, give your OC a clear backstory. For example, if they are from a noble family in the Pandora Hearts world, explain what their family is like, their upbringing, and how it has shaped them. Second, define their goals. It could be something as simple as wanting to protect a certain character or as complex as trying to change the whole system of the world. Third, give them unique quirks or habits. Maybe they always twirl their hair when they're nervous or have a particular way of speaking. This will make them more memorable.
The main characters are Break and Alice. Break is a complex character with a mysterious past and unique abilities in the Pandora Hearts universe. He is often seen as a bit of an enigma.
One idea could be a fanfic that focuses on the backstories of the minor characters in Pandora Hearts. For example, exploring the past of some of the servants in the Vessalius household. Another idea is a time - travel fanfic where a character goes back in time to change a crucial event in the Pandora Hearts story. Maybe a fanfic that imagines an alternate ending to the series, where different alliances are formed and different fates await the characters.