In the fanfiction, it could be that Hermione has developed a new type of magic that the Death Eaters are eager to control. Some of them might see her as a way to gain power over the other Death Eaters. They fight over her because they each believe they can manipulate her to their advantage. They might try to use threats, bribery or dark magic to subdue her, but she resists using her own wits and the magic she has learned at Hogwarts.
Perhaps in the fanfiction, Hermione has something that the Death Eaters are after, like a powerful magical artifact. They fight over who gets to take her prisoner first in order to extract the location of this artifact from her. It could also be that they are under the orders of Voldemort to capture her alive, but they start fighting among themselves due to personal rivalries and the desire for glory within the Death Eater ranks.
Obviously, some well - known Death Eaters like Bellatrix Lestrange would be likely main characters. Bellatrix is extremely cruel and power - hungry, so she would be eager to get her hands on Hermione. Lucius Malfoy could also be there. He is always looking for ways to gain more influence in the dark wizarding world, and Hermione might be a means to that end for him.
In this fanfiction, Hermione could rehabilitate Death Eaters by showing them the error of their ways. She may expose them to the harm they've caused to both the Muggle - born and the wizarding community at large. By making them face the consequences of their actions on a personal level, like the families they've torn apart, she might start to change their views.
Maybe Hermione discovers that one of the Death Eaters training her has a change of heart. This Death Eater then starts to help Hermione escape or undermine the other Death Eaters from within the group. It adds an interesting layer of complexity to the story.
Well, in this kind of fanfiction, perhaps Hermione is captured because she was on a solo mission to retrieve some important magical item. The Death Eaters could use her knowledge to try and break into the secrets of the Order of Phoenix. Meanwhile, Hermione could be using her wits to delay them and send out hidden signals for help.
She could face legal issues in the wizarding world. Killing is not taken lightly, even if it's Death Eaters she's killing. There might be a trial to determine if her actions were justified. If the wizarding authorities are corrupt or influenced by the wrong people, she could even be wrongly convicted.
One consequence could be that she is forced to perform dark magic against her will. This would be a huge moral struggle for her, as Hermione is a firm believer in the light side of magic. It could also change her perception of herself and her magic abilities in a very negative way.
One possible reason could be Hermione's intelligence. In the Harry Potter series, she is extremely smart, and the Death Eaters might be intrigued by someone with such powerful intellect in a fanfiction scenario. They could see her as a valuable asset or a challenging target.
Well, it could start with Hermione being kidnapped by the Death Eaters at a young age. She might be forced to attend their dark magic lessons. However, she uses her intelligence to learn about their weaknesses. For instance, she could discover a flaw in the security spells around their lair. And then, as she grows up, she could start to subtly manipulate the Death Eaters into fighting among themselves, all while pretending to be a loyal follower.
Well, perhaps in this fanfiction, there's a big misunderstanding. Harry might think that by infiltrating the Death Eaters as one of them, he can actually bring them down from the inside. So he pretends to join them, but things get out of hand as he has to constantly prove his loyalty to the dark side, which is really difficult for him.
A possible plotline could be that a Death Eater discovers Hermione has knowledge of a powerful spell or magic item that could help them overthrow Voldemort. So, they save her to get that information. For example, she might know of a way to break a powerful curse that Voldemort has placed on them.