Caterina Sforza is also a great character. She is a powerful and intelligent woman. Her political acumen and her ability to navigate the complex power - plays in the story are quite remarkable. She often uses her charm and wits to get what she wants.
Cain is quite interesting. His complex personality and his role as a vampire noble add a lot of depth to the story.
Abel Nightroad would be a great character to feature. His complex personality, being a vampire but also having a strong sense of justice, would make for interesting interactions in a crossover. Also, Esther Blanchett. She is a strong - willed human who could hold her own in different crossover scenarios. For example, in a crossover with a magical world, she could learn new spells and use her intelligence to navigate the new situation.
Aegon the Conqueror is quite interesting. He managed to unite most of Westeros under his rule with his sisters and their dragons, which was a remarkable feat.
Perhaps there are some underdog characters who manage to survive in this harsh world depicted in 'the overlord of blood and iron novel'. They might be interesting as they use their wits rather than brute force to get by. They could be the ones who add depth to the story by showing that there's more to this world than just power - hungry overlords.
There are fanfictions that focus on alternate endings. Maybe in one, Abel Nightroad doesn't sacrifice himself and instead finds a way to bring peace without such a great cost. This type of fanfiction allows fans to explore different possibilities within the Trinity Blood universe.
Aegon Targaryen is quite interesting. He was the first to conquer Westeros with his sisters and their dragons. His leadership and the way he united different forces are fascinating.
Lilith Asami is a very popular character to focus on. Her complex personality, being both powerful and having a bit of a tsundere side, makes her an interesting character to write about. Writers can explore her relationships with other characters more deeply in fanfiction.
Since I haven't read 'Trinity the Novel', I can't tell you for sure who the main characters are. However, based on the title, we can assume that there might be three main characters. They could be of different genders, ages, or backgrounds. For example, it could be an old man, a young woman, and a middle - aged man. Or perhaps they are all from different social classes, like a rich entrepreneur, a poor artist, and a middle - class teacher. The relationships between these characters would likely be complex and form the core of the story.
I don't know as I haven't read it. But it could be three main characters given the 'trinity' in the title, like a hero, a villain and a neutral figure.
One idea could be a crossover with a popular fantasy series like 'The Lord of the Rings'. Imagine the characters from Trinity Blood in the Middle - earth setting, with vampires and other supernatural beings interacting with hobbits, elves, and humans. Another idea is a crossover with a superhero universe. The vampires in Trinity Blood having to face off against superheroes or even teaming up to fight a greater evil. For example, they could join forces with the Avengers.