The fanfiction could begin with a vision. Harry has a strange dream where he is in a contract with Voldemort. When he wakes up, he discovers that it's not just a dream, and there are already signs that the contract is starting to affect his life and magic. He then has to search for answers about how this happened and what it means for him and the wizarding world.
It could start with Harry finding an old, mysterious parchment that turns out to be the contract. As soon as he touches it, some dark magic binds him to Voldemort.
Maybe it starts during a battle. Voldemort casts a spell that creates the contract. Harry is suddenly bound to Voldemort, and both of them are shocked. Then the story unfolds as they try to figure out what to do with this new situation.
It could start with Hermione realizing she is pregnant. Maybe she's in the middle of researching some ancient magic in the library at Hogwarts when she suddenly feels unwell and realizes what's going on. She then tells Harry, and they both are filled with a mix of joy and fear.
In this fanfiction, the relationship between Harry and Voldemort would be full of contradictions. Voldemort adopts Harry for his own purposes, but Harry has his own will. In the beginning, Harry may be forced to follow Voldemort's orders out of fear. As time passes, he might start to question Voldemort's actions and ideology. Voldemort, seeing Harry's growing independence, could become more controlling. This could lead to a cycle of rebellion and suppression in their relationship. Harry may also find some common ground with Voldemort in their shared loneliness or desire for power, which would add more layers to their complex relationship.
One interesting aspect could be how Harry's character would be shaped in such a fanfiction. If Voldemort was his dad, he might have a very different upbringing. Maybe he would be more conflicted about his powers and his place in the wizarding world. From a female perspective, perhaps a female character could be the one to discover this truth about Harry and help him come to terms with it.
One possible plot could be that the contract is a magical binding that forces Harry to work with Voldemort in some way. Maybe it's a deal to save the lives of his friends. So, Harry has to reluctantly follow Voldemort's orders while secretly looking for a way to break the contract.
First, re - read the original 'Harry Potter' books to get a good feel for the characters of Harry and Voldemort. Their personalities, their motives, and their powers. Then, think of a unique concept or plot that hasn't been done too often. For example, you could start with a situation where Voldemort and Harry are forced to team up for a common goal, like saving Hogwarts from a new, even greater threat.
First of all, Voldemort would probably be gloating over his capture of Harry. Harry's friends would then start to search for him. Hermione might use her vast knowledge of magic and research to figure out where Voldemort could be hiding Harry. Ron would be the more impulsive one, wanting to rush in and save Harry right away. As the story progresses, there could be a final showdown between Harry and Voldemort where Harry, despite being kidnapped, manages to turn the tables on Voldemort.
At first, their relationship would likely be one of intense enmity. Harry has fought against Voldemort, and the female Voldemort would inherit that animosity. But if they are forced to interact, say due to a common threat, they might start to respect each other's power. Harry would be cautious but also curious about her motives.
Yes, it is a rather popular trope in some corners of the Harry Potter fan community. Some fans are intrigued by the idea of combining two such polar - opposite characters in such an unexpected way. It allows for a lot of creative exploration of themes like redemption, the power of love in the face of great evil, and the blurring of the lines between good and bad.
At first, Harry would probably be extremely confused and distrustful. He's been told all his life that Voldemort is the bad guy. But as Voldemort continues to protect him from the Dursleys, Harry might start to question what he knows. He could gradually become more open to listening to Voldemort's side of the story.
In such a fanfiction, Voldemort would view Harry as his possession. He'd order Harry around, thinking he can use Harry's wolf - like abilities for his own dark deeds. However, Harry would not go down without a fight. He'd constantly be trying to undermine Voldemort from within. Their relationship would be a very strange and twisted one. Harry would have to pretend to be loyal while actually hating Voldemort with every fiber of his being. And Voldemort, being so arrogant, might not realize how much of a threat Harry still is even in his wolf form until it's too late.