Their relationship could be very different from what we expect. Maybe one is more interested in the dark arts while the other is more into the academic side of magic. So they could be constantly at odds about their future paths. But they also share a deep bond that only twins can understand, and they might communicate without words in some crucial situations.
Well, they could have a very complex relationship. On one hand, they might be extremely competitive, always trying to outdo each other in everything from academics to impressing their parents. Since they are in Slytherin, they could also team up and be a formidable duo, using their combined wits to get what they want in the wizarding world. Maybe they have a secret pact to protect each other no matter what.
The twin could change a lot. He might be the one who stops Draco from making some really bad decisions. For instance, if Draco was about to follow Voldemort's orders blindly, the twin could convince him otherwise. This would then change the whole course of Draco's actions and how he interacts with Harry Potter and his friends.
Well, in the fanfiction, they could have a very close relationship. Maybe they protect each other from the dark forces at Hogwarts. They might share secrets that no one else knows, like about their family's hidden past or their own personal fears and dreams.
Their relationship would be a mix of rivalry and mutual respect. Draco might initially look down on Annabeth because she's not from his world, but Annabeth's strength and quick thinking would soon make him change his mind. They could have some heated arguments about the best way to do things, but deep down, they would care for each other as siblings. For example, Draco might use his magic to protect Annabeth when she's in danger in the wizarding world, and Annabeth would use her strategic skills to help Draco in his own battles.
They might have a really close, protective relationship. His brother could be the one who always has Draco's back. Like when Draco gets into trouble with other students or is under pressure from the Death Eaters, his brother steps in to help him out, even if it means going against the family's traditional views sometimes.
At first, she may avoid Harry Potter altogether. However, if she discovers something that links her family's past to Harry in a way that she didn't expect, it could draw her closer to him. For example, if there was a hidden connection between the Malfoy family and Harry's parents. As she delves deeper into this connection, she might start to protect Harry from other Slytherins or even from her own brother at times. Their relationship could be one of mutual discovery and slowly - growing trust as they face the threats in the wizarding world together.
It could lead to all sorts of interesting plot twists. Maybe there's competition or a stronger bond between them.
Her character could also be very ambitious, but in a different way than Draco. She might be more focused on academic achievements. She could be the top of her class in subjects like Potions or Transfiguration, and be constantly striving to outdo herself rather than others.
Perhaps the older brother was once the heir apparent in the Malfoy family but something happened that made him lose his status. This could be due to a failed mission for the Dark Lord or a disagreement with his parents. Draco would then be in a position where he has to prove himself even more, while also trying to understand what happened to his brother and if he can help him regain his former position.
In fanfiction, their relationship could be one of unexpected friendship. Draco, initially a bully, might see a different side of himself when interacting with Harry Potter's sister. He could be drawn to her kindness and independence, which are traits he may not often encounter in his pure - blooded, Slytherin - centric world.
He could be resentful at first. After all, his parents have kept this big secret from him his whole life. But as he gets to know his twin, he might develop a sense of brotherly love. He may also start to question his family's values and actions in hiding his brother, which could lead to a change in his own character.