It's not common. Most fanfiction focuses on more positive or canon - compliant aspects of the 'Harry Potter' universe. Writers who create such a scenario might be trying to shock the readers or explore the extreme ends of a character's potential. They could be thinking about how the Malfoy family's dark side could manifest in the most horrible ways, but it's still a very dark and uncomfortable concept.
This is not a common occurrence in fanfiction. Writers might be influenced by the idea of exploring the Malfoy family's complex and often dark family dynamics. The Malfoy family has always had a reputation for being on the dark side in the 'Harry Potter' series. However, writing about Draco abusing his sister is taking it to an extreme level. It could also be a form of exploring the consequences of a character being brought up in a such a dark and prejudiced family environment. But overall, it's a very uncomfortable and not - so - common theme in the 'Harry Potter' fanfiction world.
There could be. It depends on how many authors have explored this rather disturbing concept. Some fanfictions might handle it in a more nuanced way, perhaps exploring the psychological impact on Draco. But it's also important to note that not all fanfictions of this sort will be well - written or in line with the overall spirit of the original 'Harry Potter' universe.
One way to address this is through critical analysis. Fanfiction often explores extreme scenarios, but it's important to note that this goes against the general perception of Draco's character in the original 'Harry Potter' series. Writers might be using it to show a dark 'what - if' scenario. However, it can be disturbing to some readers. It's crucial to tag such works appropriately so that readers are aware before they start reading.
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.
Some writers might do it for the humor aspect. It's quite comical to imagine a usually proud character like Draco Malfoy in such an undignified situation as wearing diapers.
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. 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 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.
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.
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.
One common trope is the protective older sister. She might be constantly looking out for Draco, especially in the dangerous wizarding world. Another is the 'forbidden friendship' trope. The sister could be friends with characters she's not supposed to be, like a Muggle - born or a member of the Order of the Phoenix. And there's also the 'rivalry' trope, where she might be in competition with other Slytherins or students from different houses.