What are the common themes in 'Harry has a crush on Sirius' fanfiction?

Yes, there are quite a few. You can start by looking on popular fanfiction websites like Archive of Our Own. Some fanfics in this theme might explore the complex emotions Harry could have for Sirius in a really interesting way, delving into their relationship and how such a crush might develop within the context of the Harry Potter universe.

One common theme could be the struggle with forbidden feelings. Since Harry and Lucius are on opposite sides in the original story, having Harry develop a crush goes against the natural order of things. Another theme might be self - discovery, as Harry has to come to terms with this unexpected attraction and what it means for his identity.

One common theme is the exploration of unrequited love. Since in the original series, Hermione is more into Ron, Harry's crush often goes unnoticed or unreciprocated, creating a lot of angst.

In these fanfictions, a common theme is the fear of rejection. Harry is often afraid to confess his crush to Charlie. And there's the theme of growth. His feelings for Charlie can lead to personal growth, like becoming more confident or more understanding of his emotions. The theme of secrecy also shows up a lot, as Harry may keep his crush a secret from others for various reasons.

Another theme is family. Since Harry lacks a proper family, Sirius becomes like family to him. Fanfictions explore how they create a family - like bond in the absence of Harry's real family. It can be really emotional.

One common theme is the internal struggle. Harry might struggle with his feelings because of the social norms in the wizarding world or because of Remus' position as his teacher/friend. Another theme could be the exploration of forbidden love, as it goes against the typical teacher - student relationship boundaries.

Many of these fanfictions have the theme of unrequited love. Cedric might be pining for Harry, but Harry may be oblivious or not feel the same way at first. This creates a lot of angst and drama in the stories. Also, there's the theme of secrecy. Cedric would need to keep his crush a secret, which adds an element of mystery and tension to the fanfiction.

In the fanfiction, Sirius having a crush on Hermione could also be due to her bravery. Hermione is not one to shy away from danger when it comes to protecting her friends or fighting for what's right. Sirius, who has also shown great courage throughout his life, might be attracted to this quality in her. Their relationship could develop in a more action - packed way. For example, during a battle against Death Eaters, Sirius might realize his feelings for Hermione as he sees her fearlessly casting spells. He could then start to leave little protective charms around for her, which she eventually discovers and starts to suspect his feelings.

A plot twist could be that Hermione is initially oblivious to Sirius' feelings. She's so focused on her studies and the fight against Voldemort that she doesn't notice the signs. But then, one day, she accidentally stumbles upon a letter Sirius was writing about his feelings for her. This throws her into a state of confusion as she never expected such a thing from him.

One common theme is loyalty. Sirius is extremely loyal to Harry, and vice versa. In many fanfictions, this loyalty is what gets them through tough situations, like when Harry is facing danger from Voldemort.