Another theme is redemption. Regulus often needs to be redeemed from the dark path he has started on, and Sirius is the one to lead him towards the light. It gives a sense of hope that people can be saved from bad choices.
The theme of sacrifice also pops up. Sirius may have to sacrifice his own safety, relationships, or even his position in the wizarding world to save Regulus. It shows the lengths one would go to for family.
One common theme is family loyalty. Sirius is driven by his love for his brother and his sense of family duty to save Regulus. It shows that no matter how estranged they may seem, family bonds are strong.
One common theme is family loyalty and betrayal. Since they come from the Black family, their actions towards each other and the family are often explored. For example, Sirius leaving the family while Regulus had a different path within it.
The themes often revolve around the idea of secrets. Regulus may be hiding secrets from Sirius, which ultimately lead to his departure. This can create a sense of mystery and suspense in the fanfiction. Another theme is the power of choice. Regulus makes a choice to leave, and this choice has far - reaching consequences for both him and Sirius. It can also explore the theme of redemption. If Regulus has made some wrong choices, his leaving could be a step towards redeeming himself, either in his own eyes or in Sirius's eyes. Additionally, the theme of the impact of the wizarding war on personal relationships is quite common, as their situation may be a microcosm of the larger conflicts and divisions in the wizarding world.
Another theme is the power of love and brotherhood. The fanfictions often show how Sirius' love and care for Regulus can overcome the barriers of the Black family's dark heritage and the dangerous magical world they live in. It's about how that connection between the two brothers can be a source of strength in difficult times.
One common theme is family loyalty. Sirius and Regulus come from the Black family, and fanfictions often explore how their loyalty to family, or lack thereof in Sirius' case, affects their actions and relationships. Another theme is redemption. Regulus, in particular, is often given a chance at redemption in these stories as he had a more complex and morally ambiguous role in the original series.
One common theme is their relationship as brothers. Many fics explore the complex dynamic between them, from their early days in the Black family to their diverging paths. For example, some stories focus on how Sirius's rebellious nature clashed with Regulus's initial loyalty to the family.
Another theme is the power of love. Harry's love for Sirius gives him the strength and courage to face the many obstacles in his way. It's a theme that's often explored in fanfiction as it was also a big part of the original books. In these stories, Harry's love overcomes things like the dark magic surrounding Azkaban or the threats from Voldemort's followers.
One common theme is redemption. Sirius often feels guilty for not being there for Harry earlier, and by saving him from abuse, he is redeeming himself in a way. For example, in many stories, he reflects on how he could have prevented Harry from going to the Dursleys in the first place.
One common theme is sacrifice. Sirius is often willing to put his own life on the line to save Harry. For example, in many fics, he battles powerful dark forces without hesitation to protect the baby.
Frequently, there's a theme of Hermione's strength in the face of abuse. Even before Sirius saves her, she might be shown as trying to resist or endure. And then after being saved, her growth and how she overcomes the trauma can be a big part of the story. The relationship between Sirius and Hermione can also explore themes of mentorship, where Sirius helps her heal and become stronger.
Another one to check out is 'Saving Regulus: Sirius's Mission'. This fanfiction delves deep into the wizarding world's politics and how Sirius has to navigate through it all to reach and save his brother. It has some really interesting characterizations and a great plot line.