It could add more complexity. If she's older, she might be more in control of the family's image and decisions, which could put Draco in a different position within the family. He might feel overshadowed or have to prove himself more.
She is often characterized as smart. Since she's a Malfoy, she has access to a lot of knowledge and magical resources. She's also usually shown as having a bit of a rebellious streak. She might not fully agree with her family's pure - blood supremacist views.
One common theme is family loyalty. The big sister often has to choose between her loyalty to the Malfoy family and her own moral compass. For example, in many fanfictions, she might be torn between supporting Draco in his tasks for the Dark Lord (as per the family's alignment in the original series) and doing what she believes is right.
One great 'Draco Malfoy big sister fanfiction' is 'The Malfoy Heiress'. It delves into the relationship between Draco and his sister in a really interesting way. The sister character is well - developed, and it shows how she navigates the complex world of Hogwarts and the Malfoy family's reputation.
A big theme is friendship. She has to find her place among the students at Hogwarts. Sometimes she befriends those outside of Slytherin, which can cause conflict within her family. Also, the theme of love often comes up. It could be a romantic love or the love for her family in a more complex way, like trying to redeem her family's name. There's also the theme of dealing with the dark side of the wizarding world, especially considering her family's association with the Death Eaters.
One interesting 'Draco Malfoy sister fanfiction' story could be about the sister being a secret rebel. She might secretly be friends with Harry and his crew, hiding it from Draco. Another could be a story where she has a special magical ability that sets her apart from the rest of the Malfoy family.
Self - discovery is also very common. Growing up as a Malfoy in the shadow of her brother, the sister often has to figure out who she really is. Is she just a Malfoy by name or does she have her own unique magic and personality? Fanfictions explore this by showing her journey, like learning new spells on her own or having a different view on the wizarding war than her family.
One common theme is family loyalty vs. personal beliefs. In many fanfictions, Draco's sister has to struggle between staying true to her family's pure - blood ideology and her own sense of right and wrong. Another theme is friendship outside of Slytherin. Since the Malfoys are Slytherins, seeing her form friendships with students from other houses is often explored.
One great Draco Malfoy's sister fanfiction is 'The Malfoy Heiress'. It delves into the life of his sister in Hogwarts, her secret friendships, and how she tries to break free from the pure - blood expectations. Another one is 'A Sister's Redemption' which shows her journey towards making amends for her family's wrongdoings.
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.