Perhaps there is a prophecy that says their union will either save or destroy the wizarding world. This would put a lot of pressure on their relationship. They would have to figure out how to fulfill the positive part of the prophecy while dealing with all the external forces that want to prevent them from being together.
One idea could be that they initially resist their bond. Draco, as a vampire, has a dark side that Hermione is wary of. But as they are forced to spend time together due to some magical event, they start to understand each other. Hermione discovers that Draco's vampire nature is not all bad, and he has his own code of honor.
One plot idea could be that Draco, being part Veela, has an instant and intense connection with Hermione. At first, they both resist it because of their past differences. But as they are forced to work together on a dangerous Hogwarts mystery, they start to understand each other more. The Veela side of Draco might give him some unique abilities that help them in their adventure, and Hermione's intelligence complements his skills. They gradually fall in love while trying to protect the school from an unknown threat.
Perhaps a plot twist could be that Draco is under the influence of a dark spell when he kidnaps Hermione, and as she tries to break the spell, she uncovers a conspiracy within the wizarding world. Or it could be that the kidnapping is a ruse set up by Hermione herself to infiltrate the Slytherin group, but Draco doesn't know it and things spiral out of control.
One possible plot twist could be that Draco's family initially opposes the marriage. His pure - blood - supremacist parents might have a hard time accepting Hermione, a Muggle - born. Another twist could be that there are dark forces at play trying to use their union for some evil purpose, perhaps related to an ancient prophecy. And a third twist could be that Hermione discovers a long - lost family secret that has some connection to the Malfoy family, which changes the dynamics of their relationship and the marriage.
One possible plot could be that at first, Hermione is completely unaware of Moony's feelings. Moony, being a werewolf, might struggle with his instincts and how to approach Hermione. He could start by subtly protecting her during dangerous situations at Hogwarts. Hermione, being the intelligent witch she is, might start to notice his strange behavior and try to figure it out through research. Eventually, Moony might confess his feelings, leading to a complex relationship as they face the challenges of wizarding society's views on such an unusual pairing.
I've read a fanfic where Draco is a werewolf and Hermione his mate. It delved deep into the magical lore of werewolves in the Harry Potter universe. The author did a great job of showing Hermione's struggle to accept this new side of Draco while also dealing with her own feelings. It's called 'The Werewolf's Mate' and it's definitely worth a read.
One interesting plot twist could be that despite being siblings, they are sorted into different houses, and this causes a rift in their relationship initially. But as the story progresses, they find common ground in their magical abilities and family secrets.
A common plot twist is that Draco is secretly working against his family's wishes to protect Hermione. For example, his family might be part of a dark plot, but he chooses to side with Hermione instead. This adds an element of conflict and drama to the story.
A common plot twist is that Hermione actually has a hidden power or ability that she reveals during her captivity. For example, she might be able to use a type of magic that Draco and his associates didn't expect, which gives her an upper hand in the situation. This could lead to a change in their relationship dynamic, from captor - captive to something more like equals.
A plotline could involve a mystery. There could be a strange phenomenon in the wizarding world that only Draco, with his godly powers, can solve. Hermione helps him in his investigations. As they dig deeper, they find out that it is related to an ancient curse that could threaten their relationship. They then have to find a way to break the curse while maintaining their bond. Also, there could be a plotline where Draco has to prove himself worthy of being a god in the eyes of the wizarding community, and Hermione is his biggest supporter throughout this process.