No. Rape is a very serious and non - consensual act, and creating fanfiction around such a disturbing and immoral topic is completely unacceptable. It goes against basic moral and ethical values.
It is extremely offensive. It can cause a great deal of emotional distress to fans who love the characters. The idea of one character raping another completely distorts the characters' relationships as they were originally intended.
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.
The negative impacts are significant. It can cause great harm to the image of the Harry Potter world that has been built on positive values. It may also make fans who are familiar with the original characters feel disgusted. Moreover, it sets a bad example for new writers in the fanfiction community, as it shows that they can create works that violate basic moral and ethical boundaries.
It could develop in a complex way. The spanking incident might initially create tension between them. Harry could be angry or resentful towards Sirius at first.
Another aspect of this fanfiction could be that Harry uses his Parseltongue ability to communicate with the snakes in Azkaban (if there are any). The snakes might have some information about Sirius since they can sense the emotions and secrets of the prisoners. Through this unique method, Harry gets closer to proving Sirius's innocence.
Perhaps in the fanfiction, Sirius is mad at Harry because Harry has befriended someone Sirius doesn't trust. Sirius, being protective of Harry, might see this new friendship as a threat. He could be worried that this person will lead Harry astray or put him in danger, and his anger towards Harry stems from his concern for Harry's well - being.
Well, a popular one is 'Sirius and Harry: A Different Kind of Family'. In this fanfiction, Sirius actually gets a chance to be a proper father figure to Harry. It shows their relationship evolving in a very heartwarming way. There's also 'The Sirius - Harry Connection'. This one plays around with the idea of a magical bond between them that goes deeper than what was shown in the books. And 'Harry's Refuge with Sirius' where Sirius provides a safe haven for Harry during tough times at Hogwarts.
One possible reason could be a misunderstanding. Maybe some false information was spread about Harry that made Sirius believe he had done something unforgivable. For example, if there were rumors that Harry was involved with dark magic in some way, Sirius, who has a strong aversion to the dark side, might be quick to disown him.
In the world of Harry Potter fanfiction, this is an extremely inappropriate and unethical concept. The Harry Potter series promotes values like love, loyalty, and courage. Sirius is an important character, and Harry respects and loves him in a proper way. Any fanfiction that goes against these values, especially with such a heinous act as rape, is not only against the nature of the original story but also against basic moral standards. Writers should strive to create fanfiction that enriches the positive aspects of the Harry Potter universe.