One common theme is redemption. Sirius often has a troubled past, and through the love story, he finds a way to redeem himself. For example, in many fics, his love for the other character makes him want to be a better person and break free from the negative reputation of his family.
Another theme is sacrifice. The lovers might have to sacrifice something for their relationship. Maybe Sirius has to sacrifice his freedom or the love interest has to sacrifice her own dreams to be with him. It adds a lot of depth to the story.
One common theme is forbidden love. Since Sirius is often involved in dangerous and complex situations in the wizarding world, his love stories are sometimes against the norms or expectations of the wizarding society. For example, he might fall in love with someone from a different magical group or a person who is on the 'wrong side' according to others.
One common theme is loyalty. Sirius is a very loyal character, and this often plays a big part in his love stories. His loyalty to his friends and his love interest is a key aspect. Another theme is the struggle against the dark times. The Marauders era was filled with danger, and his love story often has to deal with that.
Another theme is redemption through love. Sirius has had a troubled past, and in many fanfics, the love of a particular character helps him come to terms with his past mistakes and find a new path in life. It gives him a reason to be a better person.
One common theme is forbidden love. Since Sirius often has a complex relationship with the wizarding society's norms, his love stories in fanfiction often involve loving someone he's not supposed to. Another theme is redemption through love. His past mistakes or his family's dark legacy are sometimes redeemed by the power of love in these stories.
The theme of freedom is quite important too. Sirius was locked up in Azkaban for a long time, and when he escaped, he was fighting for his freedom. Fanfictions often expand on this, showing his journey to fully regain his freedom and his place in the wizarding world, while also dealing with the prejudice against him because of his supposed crimes.
One common theme is loyalty. Given their long - standing friendship, loyalty is a big part of their relationship in fanfiction. They are always there for each other through thick and thin, whether it's dealing with the wizarding world's threats or personal demons.
The theme of redemption also shows up. Since Sirius had a somewhat 'tainted' reputation in the eyes of the Black family, some fanfictions explore if Orion could have played a role in his redemption or if Sirius could have redeemed the family name in Orion's eyes.
One common theme is family. Since Sirius comes from the Black family, stories often explore how his child is related to the family's complex history, traditions, and dark secrets.
One common theme is family heritage. Since the Blacks are an old pure - blood family, many fanfictions explore how Sirius Black's mother dealt with the family's traditions and expectations. Another theme is the mother - son relationship. Given Sirius's rebellious nature, how his mother reacted to it and how it affected their relationship is often explored.
The theme of loss is also prevalent. Whether it's the loss of his freedom, his friends, or his chance at a normal life. For example, in some fanfictions, his relationship with James Potter is explored, and how his death was a huge loss for Sirius, adding to his overall sadness.