One possible reaction of Sirius could be shock. He might stand there frozen for a moment, unable to believe what he's seeing. Another reaction could be anger. If Sirius has certain expectations or feelings about James and Regulus' relationship, he could get angry at finding them together. Or he could be confused, trying to figure out how and why this is happening between his friend James and his brother Regulus.
This event could severely strain Sirius' relationship with James. If Sirius feels that James has overstepped some sort of boundary regarding Regulus, he may become distant from James. With Regulus, it could be a turning point. Sirius might start to see him in a new light, either more positively if he realizes that James is a good influence, or more negatively if he doesn't like what he sees.
Fanfiction about these three can take many forms. For example, there could be time - travel fics where Harry goes back in time and meets Regulus and Sirius when they were younger. This could lead to all sorts of interesting plot twists, like Harry trying to prevent Regulus from joining the Death Eaters in the first place. Or it could be a fic where Sirius survives and he and Harry explore the secrets of the Black family together, including things that Regulus left behind. There are also fics that focus on the emotional bonds between the characters, showing how the different personalities of Regulus, Sirius, and Harry interact and influence each other.
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.
Well, it's popular mainly due to the characters involved. Sirius and Regulus are both interesting characters from the Harry Potter universe. The concept of Sirius adopting Regulus creates a lot of drama and emotion. It's a chance to explore what could have been if things were different in their family. There are so many possibilities for plot twists and character interactions in this scenario, which draws in a lot of readers.
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.
Well, depending on the context of the fanfiction, Sirius could also be very understanding. If he knew that Harry and Hermione were just having a private conversation about important matters like their fight against Voldemort or schoolwork, he might just give them a knowing smile and say something like 'Carry on, then. Just making sure everything's all right.' He's a rather perceptive character, after all. And he trusts Harry a great deal, so he would likely give them the benefit of the doubt before assuming anything untoward.
In fanfiction, James Sirius Potter's birth is often depicted with a lot of excitement and anticipation. Writers might describe the Potter family's joy, and perhaps the presence of friends like the Weasleys during this special time.
One popular type of fanfiction about James Sirius Potter might be his adventures at Hogwarts. Writers could explore his relationships with his friends and family, like how he deals with the legacy of his famous father, Harry Potter. Maybe he gets into some mischief in the same way his father did, but also has to face new challenges specific to his own time at the school.