Fred could use his knowledge of the Weasley family's magic tricks and inventions. He might have some secret gadget or spell that can break through the barriers or spells that are being used to torture Hermione.
Common themes include 'self - discovery'. In many 'fred x hermione' fan fictions, both characters learn new things about themselves through their relationship. For example, Hermione might discover a more carefree side of herself, and Fred might realize the importance of academic pursuits. Also, 'overcoming obstacles' is a big theme. Whether it's dealing with the disapproval of others or the chaos of the wizarding world, they have to find ways to be together.
Well, in some versions, Fred might use his quick-witted magic skills. He could cast a distraction spell to draw Bellatrix's attention away from Hermione. Maybe a spell that creates multiple illusions of himself, confusing Bellatrix long enough for him to grab Hermione and disapparate them to safety.
One great 'fred x hermione' fan fiction is 'The Unlikely Bond'. It delves into how their relationship might develop in a post - war Hogwarts. Another is 'Fred's Secret Admirer' which has a really interesting take on Hermione being secretly in love with Fred long before anyone realizes. There's also 'A New Beginning for Fred and Hermione' which shows their journey of getting to know each other better outside the chaos of the main story.
One possible fanfiction could be where Fred and Hermione discover their Animagus forms together. Maybe they transform in the Forbidden Forest and have to rely on each other to get back to Hogwarts safely. Their forms could be something that represents their personalities, like Fred could be a fox, known for its cleverness and playfulness, and Hermione could be an owl, symbolizing wisdom.
One reason could be that they played a particularly mischievous prank on her that went too far. For example, if they made her late for an important exam or meeting with a professor by using one of their wild magical inventions. Hermione, being a stickler for rules and academic achievement, might lose her temper and hex them in retaliation.
Hermione, on the other hand, could become more daring. She is already brave, but this situation could push her to take risks she normally wouldn't. She might be the one to suggest trying untested spells or taking paths that are less known in order to escape. As they run, she could learn to trust her instincts more and not just rely on book knowledge.
Their relationship would likely become more serious and responsible. They'd have to put aside some of their youthful antics as they now have a child to think about, even if it's from the future. There would be a new level of trust and understanding as they work together to deal with the situation.
I'm not entirely sure if there is a specific 'Fred terrified of Hermione' fanfiction. It depends on the creativity of the fanfic writers in the fandom. Some writers might explore this unique dynamic for comedic effect, while others might use it to create a more complex and unusual plot. However, the best way to know is to search for it as I mentioned before.
One common theme is friendship exploration. Since they are not as closely paired in the original books as some other characters, fanfics often delve into how they could become better friends. For example, they might bond over a shared love of a particular subject at Hogwarts.