There's no way to know exactly without more information. However, if it's a typical graphic novel, there could be a hero or heroine, which could be Rose if the title is related to her. There might also be an antagonist, someone who opposes Rose's goals or causes trouble for her. And then there could be side characters like a wise old mentor or a mischievous little brother.
Rose and Dimitri are the central characters in this graphic novel. It's possible that Rose is a young woman full of passion and determination. She might be the one who initiates a lot of the action in the story. Dimitri, on the other hand, could be a complex character with his own secrets and motives. Their relationship is likely to be a key aspect of the story, and as the main characters, they will be the ones through whom we experience the events, emotions, and the world of the graphic novel.
Since we don't know much about the 'rose black graphic novel', the main characters could be very diverse. If the rose is a symbol in the story, perhaps there is a character who is associated with it, like a gardener or a botanist who discovers the special properties of the rose. And the 'black' aspect might introduce a character who is involved in something dark, like a villain or a morally ambiguous figure. Maybe there's also a character who tries to bridge the gap between the two concepts of 'rose' and 'black' in the story.
There could be various main characters. It might be a group of friends who discover a mysterious red rose and their lives are changed as a result. One of them could be a scientist who is intrigued by the unique properties of the red rose. Another could be an artist who is inspired by its beauty to create amazing works. Or there could be a detective - like character who is trying to solve a mystery involving the red rose.
I don't know since I haven't read it. But they could be characters related to the bone and the rose, like a character who is protecting the bone - rose entity or a character who is cursed by it.
Obviously, Rose is one of the main characters. But there may be other important characters like her friends or rivals in the vampire academy.
The main character is probably the tarot witch. Since it's in the title, she must play a crucial role. There could be other characters too. Maybe there's a mentor figure who taught her about the tarot and the significance of the black rose. Or there could be antagonists, perhaps those who want to steal the power of the black rose or misuse the tarot cards she has. Without reading the graphic novel, it's hard to say for sure who all the main characters are.
The main character is the witch associated with the tarot. Alongside her, there could be characters that are part of her backstory, like her family or mentors if she had any. In addition, there might be characters that she meets during her adventures. These could include other witches, warlocks, or even normal people who get caught up in the magical events related to her.
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.