In some 'immortal Harry Potter fanfic', Harry's immortality gives him a new perspective on life and death. He starts to question the very nature of magic and mortality. This might lead him on a spiritual journey where he tries to understand the balance between life and death in the wizarding world. He could also try to share his newfound knowledge with the younger generations of wizards, teaching them about the importance of respecting all forms of magic and life.
There are fanfics where Harry's immortality leads to him exploring the magical world in ways that were not possible before. He might discover new magical creatures in the most remote corners of the world or unlock ancient magics that were long forgotten. He could also form alliances with other immortal beings in the wizarding universe, like some old and powerful wizards who have been in hiding for centuries.
One interesting 'immortal Harry Potter fanfic' could be the ones where Harry uses his immortality to change the wizarding world's future. For example, he might be able to finally end all forms of dark magic once and for all. He could travel through time without the limitations of a normal lifespan and correct the mistakes of the past, like preventing the rise of Voldemort in the first place.
In the 'harry potter is immortal fanfic', it might explore how Harry deals with outliving his friends and loved ones. He would have to face the loneliness that comes with immortality, but also find new connections and purposes in the ever - changing wizarding world.
There are 'Harry Potter fanfic fanfic' that focus on time - travel scenarios. Imagine if a character from the later books travels back in time to the first year at Hogwarts. This can create a lot of interesting plot twists as they try to change or preserve the original story line. Also, some fanfic fanfic might center around magical creatures in a way that wasn't fully explored in the original books, like the life of a hippogriff in more detail.
One interesting Immortal Harry Potter fanfiction could be one where he uses his immortality to travel through different magical eras and learn forgotten magic. For example, he might go back to the time of the founders of Hogwarts and gain unique insights into the creation of the school and its magic.
Some 'Harry Potter and Lily Potter fanfic' might focus on alternate universes. In one such story, Lily could have survived Voldemort's attack. She would then have to raise Harry in a world that is still recovering from the Dark Lord's first rise. This would change a lot of the dynamics in the story. Harry would grow up with his mother's love and protection, and Lily would have to deal with the knowledge that Voldemort could return at any time.
One interesting plotline could be Harry's journey to fully understand and master the power of being the Master of Death. He might face challenges from dark wizards who are envious of his newfound status.
Some 'Immortal Harry Potter crossover fanfic' might involve the crossover with the 'Percy Jackson' series. Imagine Harry Potter, with his knowledge of magic, interacting with the demigods. He could share his magical knowledge, and in return, learn about the powers of the demigods. This kind of crossover often has a lot of action - packed scenes as they face common enemies together.
I'm not really in favor of the 'slaves' concept in fanfic as it can be a bit disturbing and against the positive spirit of the original 'Harry Potter' series. However, some fanfics might explore power dynamics in a more metaphorical way. But overall, the official 'Harry Potter' works focus on friendship, courage and magic, not slavery themes.
One interesting 'Harry Potter breed fanfic' story could be about the breeding of Hippogriffs in a more domesticated setting. Maybe it explores how wizards are trying to train them for various tasks like mail delivery in a different way than using owls.
One interesting 'Harry Potter Siren Fanfic' could be about a siren who uses her charm to influence the events at Hogwarts in a subtle way. Maybe she befriends Harry and tries to guide him through some challenges using her siren - like powers, which are different from magic but still effective.
There might be a fanfic where a MACUSA auror teams up with a Hogwarts student. They could be working together to stop a dark wizard who is causing chaos in both the American and British wizarding worlds. The story could explore how their different magical educations and approaches to magic come into play.