One possibility is that it's a story of redemption for Fenrir. He starts to watch over Hermione and in the process, he begins to see the good in people he's been trying to harm. As he watches her, he might be influenced by her kindness or her intelligence, and this gradually changes his view of the wizarding world and his place in it.
It could be other Death Eaters. They might suspect that Fenrir is up to something with Hermione and try to stop him. For example, Bellatrix Lestrange could be a major antagonist. She's known for her cruelty and loyalty to Voldemort, and she might not trust Fenrir's actions regarding Hermione.
Well, perhaps in the fanfiction, Fenrir Greyback is under the command of Voldemort to watch Hermione as she is seen as a threat to the Dark Lord's plans. He might follow her around Hogwarts, observing her every move. This could lead to some tense moments where Hermione senses she's being watched but can't quite figure out who it is at first. As the story progresses, she could start to set traps to catch her stalker, which would be Greyback. And there could be a big showdown between them in the end.
Perhaps it's the allure of the 'forbidden'. Fenrir Greyback is a dark and dangerous character, and exploring his relationship with Hermione in fanfiction might be an exploration of the contrast between light (Hermione) and dark (Greyback).
In one fanfiction concept, Greyback saves Hermione when she is trapped in a magical maze created by dark wizards. Greyback, being a cunning and experienced dark creature, is able to navigate the maze and get to Hermione before the maze collapses or she is killed by the various traps inside. He might save her because he senses that she has a great potential that could be useful to him in the future.
There's a fanfiction called 'Greyback's Redemption Arc'. In it, Fenrir Greyback saves Hermione from a group of Death Eaters. The author might have written it to explore the idea of redemption for a character like Greyback. Maybe he saves Hermione because he sees her as a symbol of the good in the wizarding world that he has lost touch with, and this act of saving her could be the start of his journey towards redemption.
Yes, there are likely some out there. Fanfiction is a vast world and many writers explore different and often unexpected relationships in the Harry Potter universe. However, Fenrir Greyback is a rather dark and dangerous character, so such a story would probably be very complex and perhaps a bit dark as well.
Yes, there are likely some fanfictions out there with this theme. However, it's important to note that Fenrir Greyback is a rather dark and dangerous character in the Harry Potter universe, and such a plot might explore some very complex and often disturbing ideas. Fanfiction can take many different directions with this concept, from exploring the horror of Greyback's interest to potential redemptive arcs.
One interesting fanfiction could be 'The Unlikely Pursuit'. In this, Fenrir's pursuit of Hermione is a complex web of dark intentions and her attempts to outwit him. It really plays on the danger and mystery of Greyback's character.
There might be some out there, but it's a rather unusual pairing considering Fenrir Greyback is a werewolf with dark tendencies in the Harry Potter universe and Hermione is a heroic and intelligent witch. However, some fanfiction writers like to explore unique and 'what - if' scenarios. You could start by looking on popular fanfiction websites like Archive of Our Own or Fanfiction.net.