Another plotline could be that she was cursed as a child and lost her memories. Years later, she starts to regain her memories and realizes she is a Malfoy. Draco then has to help her navigate the wizarding world that she has forgotten while also dealing with his own feelings about having a long lost sister. It could involve adventures in finding a way to break the curse completely.
A common plotline is the discovery of the sister. She might be found in an unexpected place like a muggle orphanage or a hidden wizarding community. Another plotline is her relationship with Draco. At first, they might be at odds because of their different upbringings, but later they grow closer.
A plotline could involve Draco's family trying to hide his non - pure - blood origin for generations. When Draco finds out, he could start to question his family's values and actions. He might then try to find out who his non - pure - blood ancestors were and what their story was. Maybe he forms an unlikely alliance with some non - pure - blood characters in Hogwarts as he tries to come to terms with his new identity. There could also be a plot where the discovery of his non - pure - blood status changes his relationship with Harry Potter. Instead of being rivals, they could become allies as Draco realizes the unfairness of the blood - based discrimination in the wizarding world.
Perhaps the twin sister has a special power or ability that Draco initially wants to use for his own gain. He tries to befriend her under false pretenses. But as he gets to know her better, he realizes she's not just a means to an end. For example, if she has the power to communicate with magical creatures, Draco, who is interested in the more elite aspects of the wizarding world, might see this as an opportunity to impress his family. However, as he spends time with her, he starts to care about her for who she is, and they develop a relationship that goes against the expectations of their respective friend groups and families.
One great fanfiction on this topic is 'The Lost Malfoy'. It delves deep into the character of Draco's long lost sister. She has been living in the Muggle world all this time and discovers her true identity. The story is full of heart - warming moments as she tries to fit into the wizarding world she never knew she belonged to.
Another plot could be that she was raised in a different village under false pretenses, believing she was an orphan. When she discovers she is Naruto's sister, she has to decide whether to stay in the village she grew up in or return to Konoha. Along the way, she has to face her own identity crisis and deal with the political implications of her new - found family relation.
One possible plotline could be Draco trying to hide his squib status from his family. He might go to great lengths to fake being a wizard, like using magic - like tricks or relying on others to do magic for him in front of his family. Another plotline could be Draco befriending other squibs and forming a sort of underground community where they support each other and try to prove their worth in the wizarding world. Or, he could be discovered as a squib by his enemies, like Harry Potter and his friends, and instead of the usual animosity, they feel pity and try to help him come to terms with his new reality.
One reason could be to explore the darker side of the Malfoy family dynamics. The Malfoys are often portrayed as a rather complex family in the 'Harry Potter' series, and this could be a way to dig deeper into their potential dysfunctions.
One interesting fanfiction could be 'The Lost Malfoy'. In this story, Draco's lost sister is found to have unique magical abilities that she has been hiding. It shows her journey of trying to fit into the Malfoy family and the wizarding world while dealing with the secrets of her past.
One possible plotline could be that Bella and Draco meet in a magical crossover event. They initially dislike each other due to their different upbringings, but as they are forced to work together to solve a mystery that threatens both their worlds, they start to understand and respect each other. There could be no romantic or inappropriate elements, just a story of two characters from different universes finding common ground.
Well, he could end up being a rival to some of the noble houses in Westeros. Maybe he'd use his Slytherin cunning to try and gain power. He might start off as an outcast, just like he was at Hogwarts, but gradually find a way to insert himself into the political games of the Seven Kingdoms.