One reason could be that they see her intelligence as an asset. Hermione is known for her brilliant mind, and Slytherins, who value cunning and resourcefulness, might respect that. They could also recognize her strength in the face of adversity and be drawn to protect her as a way to show their own growth beyond the typical Slytherin - Gryffindor rivalry. In some fanfictions, a Slytherin might have a personal connection or debt to Hermione, which leads to their protective nature towards her.
There's also 'The Slytherin Guard for Hermione'. This fanfic shows how some Slytherins, who have grown tired of the house's bad reputation, choose Hermione as the symbol of their change. They protect her from dark wizards who target her for her Muggle - born status. It's an interesting take on how Slytherins can be allies.
There are fanfictions where a Slytherin forms a study group with Hermione. And when other students try to disrupt her studies or cause her trouble, the Slytherin stands up for her. Also, in some stories, a Slytherin who has a secret crush on Hermione will protect her from any sort of harm, whether it's from a jealous rival or a dangerous magical creature that gets loose on the school grounds.
Another theme is the idea of hidden alliances. In many of these fanfics, the Slytherins form a secret group to protect Hermione. This adds an element of mystery and intrigue as they work behind the scenes to keep her safe from threats, both inside and outside Hogwarts.
One great Hermione and Slytherins fanfiction is 'A Different Sort of Bond'. It explores the relationship between Hermione and a group of Slytherins in a really interesting way. The characters are well - written and it shows how Hermione can break the stereotypes associated with Gryffindors and Slytherins.
Well, in some versions, they might use their knowledge of the castle's secret passages to lead the troll away from Hermione. They could also work together as a team, using their Slytherin cunning to outwit the troll.
One way their protectiveness shows is in the social aspect. Slytherins are known for their loyalty to their own. They would include Draco in all their activities and not let him feel left out. If there were rumors going around about Draco, they would quickly squash them. In dueling situations, they might form a protective circle around him, using their skills to keep any opponents at bay. And when it comes to academic competitions, they would support Draco wholeheartedly, even helping him study in secret if needed.
One great fanfiction with this plot is 'Slytherin's Compassion'. In it, a group of Slytherins come across an injured Hermione in the Forbidden Forest. They initially have mixed reactions but end up helping her. It shows a different side of the Slytherin house.
The allure also lies in the exploration of Hogwarts house politics. Fanfictions in this genre often break the traditional boundaries between houses. They show that students from Gryffindor and Slytherin can work together, fall in love, or form strong friendships. It gives readers a new perspective on the wizarding world that J.K. Rowling created, which is very appealing.