What could be the plot of a fanfiction where Harry Potter has an older sister?

She could be a half - blood like Harry. Maybe her mother was a muggle - born witch and her father was a pure - blood wizard. This mixed heritage could give her a unique perspective on the wizarding world's issues regarding blood purity.

She could be involved in the Akatsuki plot in some way. In the fanfiction, she might have been sent on a mission that led her to cross paths with the Akatsuki members. This could create a whole new storyline where Naruto has to rescue his sister from the clutches of the Akatsuki, adding more depth to the Naruto universe.

The sister might have her own group of friends in the wizarding world. When she takes in Harry, she brings him into this circle. They all contribute to his upbringing. For example, one friend could be a potions expert and teach Harry about potions in a fun way. Another could be a great dueler and train Harry in combat magic. His sister coordinates all this, ensuring Harry gets a well - rounded magical education and a loving family environment.

Well, perhaps the older sister could be a powerful witch. She might protect Harry from the Dursleys' mistreatment in a more forceful way than in the original story. For example, she could use magic to make sure Harry has enough food and a proper room.

One possible plot could be that Draco's older sister, let's call her Astoria for example, starts to develop feelings for Harry while trying to bridge the gap between the Slytherin and Gryffindor houses. She might see the good in Harry that Draco refuses to acknowledge at first. This could lead to a series of events where she has to choose between her family's traditional views and her new - found respect and love for Harry.

There could be various storylines involving Heather as an older sister in Harry Potter fanfiction. Maybe she's a Gryffindor like Harry and helps him out in his adventures, or she could be a Slytherin with her own complex motives.

She could play a protective role towards Harry. Since she's older, she might feel a strong sense of responsibility for her younger brother. For instance, she could be the one who first discovers some of the secrets about Voldemort's return and warns Harry.

One possibility is that Harry discovers a long - lost sister and takes on the role of a protector. He might teach her magic in secret, away from the prying eyes of the wizarding world authorities. Maybe they live in a hidden cottage and he passes on the skills he learned at Hogwarts to her.

In this fanfiction, the older brother of the Boy - Who - Lived (BWL) might have a very different relationship with the wizarding world. He could be an outcast because he is overshadowed by his younger brother's fame. So, he might decide to create his own path, away from the typical Hogwarts hero - worship. But when danger really comes to Harry, he steps up. He might have some knowledge about the dark arts that he uses to fight the enemies in a more unorthodox way compared to Dumbledore's side.

It would likely change the power dynamic. The sister could be a popular and powerful figure at Hogwarts. She might be in a different house than Harry, which could lead to some friendly rivalries between the houses in a different way. For example, if she was in Slytherin, there could be more cooperation between Gryffindor and Slytherin because of their family bond.