Well, it's possible that her magic becomes more attuned to male - dominated magical fields. If in her normal form she was great at academic magic, as a boy she might find she has a natural affinity for combat magic. She could discover that she can learn certain spells quicker, like the more aggressive hexes and jinxes. This change in her magic could also lead to her having different magical relationships. For instance, she might attract the attention of male magical creatures that were previously indifferent to her, and they could offer her new forms of magical knowledge or assistance.
When Hermione turns into a vampire, her magic could take on a darker tint. Not in the sense of being evil, but more in terms of its appearance. Maybe her spells now have a red or purple glow instead of the usual blue or white. Also, her ability to perform blood - related magic could be magnified. Since vampires are associated with blood, she could use her own vampiric essence to fuel spells that involve life force or healing, but in a different way than traditional magic.
Well, her communication changes a great deal. As a cat, she can't speak in the normal way. So, in some fanfictions, she has to find new ways to express herself. This could be through body language or by leading her friends to things she wants them to see. Also, her relationship with danger might change. She might be more cautious as a cat, or she could be bolder because she has new cat - like abilities to rely on. In some stories, she also becomes more attuned to the natural magic around Hogwarts in her cat form, which is an interesting development of her character.
At first, Harry and Ron might be a bit freaked out. But Harry, being more open - minded, would quickly try to understand. Ron, on the other hand, might take some time to get used to it. Eventually, they would realize that Hermione is still Hermione, and they would support her in finding a way to change back if she wanted to. Their friendship would be tested, but ultimately become stronger as they face this strange situation together.
It changes the story dynamics in several ways. Firstly, the character's perception within the wizarding world would be different. As a boy, Hermione might face different expectations and prejudices. His friendships could also take on new forms. He might bond with male characters over typically'male' interests in the wizarding world. And in group situations, his role could be more of a leader among the boys rather than the girl - power - house Hermione was, which would affect how the group tackles problems.
He might become more aggressive due to the dragon's natural instincts. Dragons are often seen as fierce creatures, so he could be quicker to anger.
Her curiosity might become even more intense. As a dragon, she has new abilities and a new form to explore, so she'll be eager to figure out all the ins and outs. For example, she'll be curious about how her dragon body works mechanically and magically.
She could become more solitary. As a vampire, she might feel like an outcast, different from her friends. This could make her withdraw from social interactions she used to enjoy.
Hermione's character changes in many ways. Firstly, she has to adapt to a new physical form which brings out a more aggressive side in some situations. This is a big contrast to her usually calm and rational self. Emotionally, she may feel more isolated as she fears how others will react. However, this also makes her more independent and self - reliant. She starts to question the norms of the wizarding society regarding werewolves and becomes a more vocal advocate for change.
It changes her character quite a bit. Normally, Hermione is known for her strict adherence to rules. But as a thief, she becomes a bit of a rebel. She might be more willing to take risks and break the rules for what she believes is a greater good.
One idea could be that when Hermione turns into a boy, she has to deal with different social dynamics in Hogwarts. For example, she might be treated differently by the boys in Gryffindor. Some might be more competitive with her, while others might befriend her in a new way. In the fanfiction, it could explore how she uses her now - male identity to her advantage in magic studies, perhaps being able to participate in all - male magical dueling clubs or something similar. And she could also have an interesting time trying to hide this transformation from her professors, especially McGonagall who is very perceptive.