Well, a major aspect is the impact on the overall story arc. In these fanfictions, the fight against Voldemort takes on a whole new meaning. Harry being a Horcrux means that his very existence is intertwined with Voldemort's. There's also the element of secrecy and revelation. How and when the other characters find out about Harry being a Horcrux can be a crucial part of the plot. And, of course, there's the magical mechanics of what it means to be a Horcrux. How does it affect Harry's magic? How can it be destroyed without killing Harry? These are all things that are often explored.
His reaction would likely be very different. At first, he might be angry that he didn't know this before. But then, he could start to see opportunities. He may think that if he can somehow control Harry as a Horcrux, he can gain more power. So, he might change his strategy from simply trying to murder Harry to trying to subdue him in a different way.
Well, it depends on how the author writes it. Maybe Voldemort would initially be in disbelief. But once he accepts it, he could start to manipulate Harry in different ways. He might think that by controlling Harry, he can control the Horcrux within him. This could create some really interesting plot twists where Harry has to resist Voldemort's attempts at a much deeper level than just physical attacks.
One popular 'Harry is Voldemort's Horcrux' fanfiction is 'The Horcrux Within'. It delves deep into how Harry's new status as a Horcrux affects his relationships with his friends, especially Hermione and Ron. It also shows his internal struggle as he tries to come to terms with this dark connection to Voldemort.
There's 'Harry's Hidden Horcrux'. This fanfic could show Harry creating a Horcrux during a time of great emotional turmoil. Maybe he's trying to preserve a part of himself that he feels is being lost in the fight against Voldemort. It would likely delve into the dark magic aspects and how it changes Harry.
One interesting Harry and Hermione Horcrux fanfiction could be 'The Horcrux Hunt'. In this fic, Harry and Hermione embark on a dangerous journey to find and destroy all the Horcruxes together. Their friendship deepens as they face numerous challenges along the way.
One popular 'Harry absorbs Horcrux' fanfiction might be 'The Horcrux Within'. It delves into how Harry's character changes as he absorbs the Horcrux. The story explores his internal struggles and how it affects his relationships with his friends at Hogwarts. Another could be 'Absorbing the Darkness' which focuses on the magical implications of such an event. It shows how Harry has to learn to control the new power within him that comes with the absorbed Horcrux.
Power imbalance is a key element. Voldemort, with his great magical power, lords over Harry. For example, he might use magic to control Harry's movements or actions. Another element is the psychological aspect. Harry's submissiveness often involves him having to endure Voldemort's mental games and taunts.
In some fanfictions, when Harry absorbs the Horcrux, it could lead to a moral dilemma within him. He has to struggle with the dark influence of the Horcrux while still trying to be the good wizard he is. This internal conflict can make for a really engaging story, with Harry constantly fighting his inner demons and trying to separate his own identity from that of Voldemort's.
They're interesting because it's a unique twist on the original Harry Potter story. It adds a whole new layer of complexity to Harry's character. Instead of just fighting against Horcruxes, he has to deal with being a part of that dark magic in a way.
One common theme is the struggle for identity. When Harry is Voldemort's possession, he often has to fight to retain his sense of self. Another theme is power imbalance. Voldemort is extremely powerful, and Harry's new position as his possession creates a huge power gap that the story often explores.