Well, perhaps in the fanfiction Bellatrix sees Hermione as a key obstacle in achieving her own goals. Maybe Hermione has discovered something that could undermine Bellatrix's power or status within the Death Eaters. Or it could be a way for the author to explore the darkest depths of Bellatrix's character, showing how far she is willing to go to assert her dominance over those she considers inferior, and Hermione, with her Muggle - born status and intelligence, is the perfect victim in her eyes.
One reason could be pure hatred. Bellatrix despises Muggle - borns, and Hermione being a very intelligent and powerful Muggle - born would be a prime target for her wrath. Another could be jealousy. Hermione's skills and knowledge might make Bellatrix feel inferior, leading her to lash out.
Yes, there are likely fanfictions out there with such a plot. The 'Harry Potter' fandom is vast and diverse, and some fanfiction authors explore dark and alternate storylines. However, these often deviate from the original positive and heroic themes of the series.
One possible plot could be that Bellatrix captures Hermione and tries to torture her for information about Harry. But Hermione, using her wits and some new-found powerful magic she has been secretly studying, manages to turn the tables and kill Bellatrix in self - defense.
Perhaps it's about the idea of corruption. Bellatrix, being on the dark side, might be obsessed with Hermione as a symbol of the light side that she wants to taint. In fanfiction, it could be a way to show the struggle between good and evil in a more personal and complex way. Also, Hermione's courage in the face of danger might be something that attracts Bellatrix's attention in these fictional stories.
Luna Lovegood might be involved. She could provide some unique magical items or knowledge to Hermione that helps in the fight against Bellatrix. Also, Severus Snape could be a character in the fanfiction. His complex relationship with both the Order of the Phoenix and the Death Eaters could add an interesting layer to the story. Maybe he has some information that Hermione needs to defeat Bellatrix.
Perhaps in the fanfiction, Bellatrix stabs Hermione as a way to get to Harry Potter. She might think that by harming Hermione, she can draw Harry out and into a trap. Hermione is one of Harry's closest friends, so this would be a strategic move on Bellatrix's part.
One possible motive could be jealousy. Bellatrix is extremely loyal to Voldemort, and Hermione is a very powerful and intelligent witch from the side opposing Voldemort. Bellatrix might see Hermione as a threat and also be jealous of the attention Hermione gets from Harry and Ron. So, she tortures Hermione to try and break her spirit and prove her own superiority.
One popular fanfiction that might include such a scene could be 'The Darkest of Bonds'. In this fic, their interactions are complex and full of tension. However, it's important to note that fanfictions vary greatly in quality and content.
One reason could be a sense of kinship. Bellatrix might see a part of herself in Hermione's fierce loyalty and determination. Another could be a change of heart. Maybe she realizes the error of her ways and decides to protect Hermione as a way to atone for her past actions.
Living with Bellatrix would be a terrifying experience for Hermione. However, she would rely on her wits. She would probably keep her Gryffindor courage in check and act more like a Slytherin, being cunning and sly. She might start to understand Bellatrix's insecurities and use them to her benefit. For instance, if Bellatrix is insecure about her standing among the Death Eaters, Hermione could offer advice that seems helpful but actually undermines Bellatrix's loyalty to Voldemort. And she would constantly be on the lookout for any signs of kindness or humanity in Bellatrix, hoping to use it as a way to change the situation.
In Hermione and Bellatrix fanfiction, the power dynamic is often an interesting point. Bellatrix has a great deal of power as a Death Eater, but Hermione has her own kind of power in her knowledge and magic skills. Some fanfictions may show a battle of wills between them, where Hermione refuses to be intimidated by Bellatrix's threats. This can lead to some really intense and exciting storylines, like when Hermione stands up to Bellatrix in a duel - like situation in a magically - created arena within the fanfic's plot.