A powerful sorceress might be one of the main characters. She could use her magic to influence the outcome of battles in the rose war. Maybe she has her own motives and goals that are not immediately clear.
I'm not sure as we don't have enough details about the specific fantassy novel. But usually, there would be leaders of the two sides in the war, perhaps a brave knight on one side and a cunning wizard on the other.
I don't know as I haven't read this specific 'the white rose fantasy novel'. It could be a young hero or heroine who is on a mission related to the white rose.
Another possible theme is loyalty. Characters in the novel may have to choose which side to be on during the rose war. Their loyalty to a particular cause, leader or group could be tested, and this could be explored in various plotlines.
I'm not sure exactly who the main characters are without having read the novels. But typically in fantasy novels, there might be a young hero or heroine. Maybe a brave knight - like character who has to face challenges related to the rose and the dagger in the story.
Since I don't know the exact 'rose novel', I can't say for sure. But it could have a female protagonist who is drawn to the beauty and mystery of the roses in the story.
Without reading the 'the white rose novel', it's really difficult to determine the main characters. However, it's possible that there is a gardener or botanist type of character if the white rose has some special botanical significance in the story. Or perhaps there are two characters from different social classes whose paths cross because of the white rose, like a rich heir and a poor artist, and their relationship develops around this symbol of the white rose.
William of Baskerville is a central figure. He's a learned man with great deductive skills. He's sent to investigate the strange happenings in the abbey. Adso of Melk is his sidekick, so to speak. As a young novice, he provides a different perspective and is in awe of William's abilities. Jorge of Burgos, the librarian, is a complex character. His actions and decisions drive much of the plot as he has a strong influence over the abbey and its secrets.
I'm not sure exactly as I haven't read it. But it could be a king or queen since there is a crown in the title. And maybe a person who is associated with the rose, perhaps a gardener or a noble who has a special relationship with the flower.
In the 'Rose Madder' novel, the central character is a woman seeking to escape her violent husband. She is the focus as we follow her journey of escape and new beginnings. Her husband is a key figure too, being the antagonist. There might be other minor characters that she meets during her new life, but these two are the most prominent ones in the overall narrative.
Briar Rose is definitely one of the main characters. And probably there is a prince who wakes her up from the long sleep.