A really interesting plot twist could be that Blaise is under a magical curse that affects his relationship with Hermione. The curse could be related to an old feud between their families that was long forgotten. As the story progresses, Hermione might start to notice strange behavior from Blaise and tries to figure out what's wrong. This could lead to a race against time to break the curse before it causes some serious harm, not only to their relationship but also to the wizarding world as a whole. Maybe the curse is slowly spreading and affecting other aspects of the magical realm, and only by Blaise and Hermione working together can they find a solution.
Maybe there's a plot twist where Hermione discovers that Blaise has a hidden past or a secret mission that he hasn't told her about. This could put a strain on their engagement as she questions whether she really knows him. Or perhaps there's a magical curse that gets in the way of their relationship, and they have to find a way to break it in order to have a successful engagement.
Hermione might become more confident in her Slytherin - like traits. Since Blaise is her brother, she could learn from his Slytherin ways of being cunning and resourceful. This would add a new layer to her Gryffindor - centered character.
One possible plot twist could be that the betrothal was a setup by a dark wizard to gain control over Harry. Maybe they thought by tying him to a Slytherin like Blaise, they could manipulate Harry more easily.
She might discover a new side of the Weasley family. Since Ron's older brother is likely to have different experiences and skills compared to Ron, Hermione could learn a great deal from him. For instance, if he's more involved in magical research, he could share some of his findings with her.
One possible plot twist could be that Hermione's magical abilities take on a new dimension under Narcissa's influence. Maybe she discovers a different kind of magic that the Malfoy family has secretly been practicing. Another could be that Hermione's relationship with the wizarding world at large changes. She might become more of an insider in the pure - blood society, which would cause a stir among her friends like Harry and Ron. Also, her academic pursuits could shift as Narcissa encourages her to study different areas of magic that are more in line with the Malfoy family's interests.
Well, it could be that Hermione is under a spell when she marries Rowle. The fanfiction could then revolve around how she breaks the spell and what she does after realizing she's been forced into this marriage. She might find that Rowle has some redeeming qualities despite the situation, and they could either part ways amicably or decide to work on a real relationship.
One possible plot twist could be Hermione getting tired of being overlooked in the wizarding world despite her intelligence. She might turn to the Dark Arts out of a sense of vengeance. For example, she could start using her knowledge of spells to manipulate those who have underestimated her, like some of the pure - blood supremacists. Maybe she'd form her own group of followers who are also disillusioned with the current state of the wizarding world order.
One plot twist could be that Hermione discovers she has a hidden connection to the Malfoy family, like she's a long - lost relative. This would add a whole new layer to her being raised by them. Another could be that she uses her knowledge of both the Gryffindor and Malfoy ways to broker peace between the two factions in the wizarding world that are often at odds. Maybe she uncovers a secret plot within the Malfoy family that goes against her new - found loyalty to them, forcing her to choose between her upbringing and what she believes is right.
Well, perhaps the phoenix is actually a guardian of a powerful magic that only Hermione and Severus can unlock together. But there's a catch. They have to overcome their initial distrust and dislike for each other. This would lead to a lot of tense and interesting scenes as they try to figure out how to work together without killing each other first.
In this fanfiction, the pregnancy could be a result of a magical accident. Hermione and Blaise are working on a powerful spell, and something goes wrong. Now they have to deal with the consequences. Hermione might be scared but also determined to face it. Blaise would need to step up and support her. They might have to go on a journey to find a way to reverse the spell if they don't want the pregnancy, or they could accept it and start building a family. Along the way, they would face many obstacles, like other wizards who might want to use the situation for their own gain.