When the soul horcrux wakes up in Harry, it likely creates a major conflict. It might start influencing his thoughts and actions, or it could trigger a battle within Harry himself as he tries to resist its influence.
Well, there could be a lot of drama. The master might face challenges related to the concubine's status and try to find a way back to their original power. Also, there could be romantic subplots and power struggles within the palace or whatever setting it is.
Well, perhaps they could start the day with a friendly chat over breakfast. Harry might share some of his wizarding world stories with Gabrielle, and she could be really fascinated by them.
Well, it could be a story where Harry and Fleur are part of a secret mission together. They had to stay the night in a hidden place for safety. When Harry wakes up with Fleur, they might start discussing their next moves in a very friendly and perhaps a bit flirty way. They could exchange stories about their experiences at Hogwarts and Beauxbatons respectively, and then realize they have more in common than they thought.
Well, perhaps a plot where Harry wakes up as a girl and discovers new magical abilities that are more commonly associated with female witches. She might then have to learn how to control and use these abilities while also coming to terms with her changed physical form. It could also involve a romantic sub - plot where characters who previously saw Harry as a boy now have different feelings towards her as a girl.
One possible plot could be that the girl is a fellow student at Hogwarts who has fainted during a dangerous situation, like a duel gone wrong in a secret passage. Harry, being the heroic type, uses a spell to wake her up. Then they end up having to work together to get out of the passage before it closes or some other threat arrives.
New and upcoming writers could also write a great one. They might bring a fresh perspective to the idea. Maybe a young writer who has a vivid imagination and is a big fan of both Harry and Gabrielle as characters. They could come up with unique scenarios and interactions between the two that we haven't seen before.
Obviously, Harry would be the main character, just in a female form. Hermione would also be a very important character. She could be the one to help Harry understand and navigate the new experiences of being a girl in the wizarding world. Ron might also be there, and his reactions to Harry's transformation could add some interesting dynamics to the story.
In a 'harry potter and the last horcrux fanfic', it may center around the significance of the last Horcrux. It could depict the emotional and mental state of Harry as he approaches the end of his long journey. There could be unexpected twists, like the Horcrux being hidden in a place no one suspected. It might also expand on the lore of Horcruxes, for example, by showing different ways to detect or destroy them that were not mentioned in the original series.
One interesting 'horcrux harry fanfic' story could be about Harry finding a way to destroy all the horcruxes in a completely new and unexpected manner. Maybe he discovers a hidden spell that can disintegrate the horcruxes without the use of the sword of Gryffindor or the basilisk fang. Another could be a story where Harry becomes a horcrux in a different way than in the original series, and how he has to deal with the implications of that. It could involve him having to face Voldemort in a more complex psychological battle.
Well, identity exploration is a big one. Harry has to figure out what it means to be a Horcrux on top of being the Boy Who Lived. There is also the theme of moral conflict. He is part of Voldemort's dark creation, yet he is the symbol of hope. How does he balance this? Another common theme is the exploration of magic. Since he is a Horcrux, there could be new and different magical aspects to his being that fanfic writers can explore, like how his Horcrux - ness affects his magical abilities or his connection to other magical objects.