Well, perhaps in the fanfiction, Blaise and Hermione as twins are separated at birth due to some dark magic plot. As they grow up in different environments (Blaise in Slytherin - like family and Hermione in a Muggle - loving family), when they finally meet at Hogwarts, they initially clash but then slowly realize their bond and team up against common enemies, like some pure - blood supremacist groups in the school.
One interesting plot could be that Blaise and Hermione, as twins in this fanfic, discover they have a hidden magical connection that no one else has. They might use this connection to solve mysteries in Hogwarts that stump even the professors.
In some fanfictions, Blaise and Hermione as twins might be given a special prophecy. They are the only ones who can prevent a great magical disaster. So, they embark on a journey together, exploring ancient magic, learning from different magical creatures, and using their combined knowledge (Blaise's Slytherin cunning and Hermione's vast book - learning) to fulfill the prophecy and save the wizarding world.
There's 'Twins in a New World'. In this fanfiction, Hermione and Blaise as twins are thrown into a different magical realm. It shows how they adapt together, with their individual strengths and weaknesses coming to the fore. It's really engaging as it also delves into the politics of this new magical world.
They're popular because it's an interesting and unexpected pairing. Fans like to explore new relationships that deviate from the original canon. Hermione and Blaise come from different backgrounds in the HP world, so seeing them as twins creates a whole new dynamic to play with.
Another plot might involve them teaming up against a common enemy. Maybe a dark wizard is targeting them because of their combined magical abilities and they have to use their brotherly bond to overcome the threat. They could learn new spells together and support each other in battles.
One idea could be that Hermione is turned into a vampire against her will and Blaise, who has been a vampire for a long time, takes it upon himself to teach her how to control her new powers. He could introduce her to the vampire society and they end up falling in love during the process.
A plot could be set post - Hogwarts. Draco and Blaise are trying to redeem their families' reputations in the wizarding world. Hermione, being the brilliant witch she is, is working on some important magical research. Their paths cross when a dark magic artifact resurfaces. Hermione believes it can be used for good if studied properly, while Draco and Blaise are worried it will fall into the wrong hands again. So they team up to protect it and study it.
Well, in some fanfictions, a great plot is their relationship with their Hogwarts houses. For example, if Harry is in Gryffindor and Tom in Slytherin, there could be a lot of tension and yet also a deep bond that forms as they try to understand each other's values and motives within their respective houses.
One interesting plot could be that Bella and Elena discover they have a long - lost family connection that ties them to a mysterious supernatural heritage. This could lead them on an adventure to uncover the secrets of their past.
One interesting plotline could be the three of them working together on a complex magical project at Hogwarts. Maybe they're trying to create a new spell or potion that could revolutionize the wizarding world.
It's interesting because it combines two very different characters. Hermione is known for her studiousness and loyalty to her friends, while Blaise has that Slytherin mystery. Merging them as siblings gives a whole new dynamic to explore.
One idea could be a story where they are all assigned to a special project at Hogwarts. Blaise, Draco, Hermione, and Theo have to put aside their differences and work together. Maybe it's a research project on a long - forgotten magic that could potentially be dangerous if misused. As they dig deeper, they start to understand each other better. Hermione's knowledge, combined with the Slytherins' cunning, makes for an interesting dynamic.