In the fanfiction, Regulus being sorted into Hufflepuff could lead to a whole new set of adventures. He might discover that Hufflepuff has its own hidden treasures or secrets that are related to the fight against the Dark Arts. His journey could involve uniting with other Hufflepuffs to uncover these secrets and use them to oppose Voldemort. This would be different from the traditional Slytherin - centered stories about Regulus and show a new side of his character as a Hufflepuff student, full of courage (which is also a Hufflepuff trait in a way as it takes courage to be different) and loyalty to his new - found house.
A fanfiction with this premise might explore how Regulus changes Hufflepuff. His Slytherin upbringing could bring in a different perspective. He might introduce new ways of thinking about magic and the wizarding world to his Hufflepuff housemates. For instance, he could have a more cut - throat approach to Quidditch (a Slytherin trait) which could initially shock the Hufflepuffs but then inspire them to be more competitive in a healthy way. At the same time, Hufflepuff's values start to change him too, making him more open - hearted and less concerned with pure - blood status.
In a fanfiction where Regulus Black is sorted into Hufflepuff, he might face a lot of prejudice from his own family. They could be disappointed that he's not in Slytherin. But in Hufflepuff, he finds true friends who support him. He could use his intelligence (which is often associated with Slytherins) to help Hufflepuff in things like academic competitions. This would show that being in Hufflepuff doesn't mean he lacks the traits that other houses value.
For creativity. It offers a fresh take on the Harry Potter story. Instead of the typical Gryffindor sorting, Hufflepuff provides a different set of values and dynamics to explore.
One interesting plotline could be Harry's struggle to fit in with the Hufflepuff values at first. Since he's always been seen as a potential Gryffindor, he has to learn about hard work, loyalty, and fairness in a new way.
A plotline could involve Harry's friendship with Cedric Diggory. In this fanfiction, they could become even closer friends as housemates. Harry might learn from Cedric's fairness and good - naturedness. They could team up to compete in some inter - house challenges that are unique to Hufflepuff. And when Cedric faces difficulties, Harry uses his Gryffindor - like courage along with his new - found Hufflepuff loyalty to support him.
One popular one might be 'The Hufflepuff's Adventure'. It often shows Harry's unique journey within Hufflepuff, making new friends and facing challenges in a different way compared to the original story.
Obviously, Harry Potter himself would be the central character. His journey of adjusting to Hufflepuff house would be the main focus.
Sirius would probably be angry at first in the fanfiction. He left his family and Regulus was still part of it. But as the story progresses, he might start to feel some regret or longing for his brother. James would be supportive of Sirius' emotions, and Remus would be the voice of reason, analyzing Regulus' actions and motives.
It could be full of family secrets and revelations. Harry might discover his true heritage in a dramatic way and have to deal with the implications of being related to Regulus.
In the afterlife, their relationship could be one of healing. Regulus, having made amends for his past mistakes in a way, could finally have an open and honest conversation with Sirius. They might start to understand each other's motives better. Sirius could see that Regulus was always trying to fight the dark forces in his own way, and Regulus could understand Sirius' need for freedom and justice. They could spend time reminiscing about their childhood, both the good and the bad parts, and form a closer bond than they ever had in life.
Often, Harry will develop a stronger sense of community. Hufflepuff is very much a house that emphasizes togetherness. So he'll start to think more about the group as a whole rather than just himself. He might get involved in house - wide projects to improve the living conditions or organize social events for his housemates.