Well, the relationship development is likely to be a slow and gradual process. Harry sending love letters is a very unexpected move. Voldemort is so used to hatred and power struggles. When the letters start arriving, Voldemort might be dismissive at first. But as Harry keeps sending them, Voldemort may start to have some internal conflict. He may be curious about this new side of Harry and why he is doing this. This could lead to a series of interactions between them that are not based on fighting, but rather on trying to understand each other's motives. As a result, their relationship could shift from one of pure enmity to a more nuanced and strange connection.
It might start with Voldemort's initial curiosity. He realizes Harry is more than just a threat. So he begins to observe Harry closely. As time goes by, Voldemort may start to feel a strange sense of connection, like he's the only one who truly understands Harry's power.
It could start with a lot of animosity on Harry's part, but as he is trained, he might start to see Voldemort in a different light. Maybe he begins to understand Voldemort's motives, though not necessarily agreeing with them.
At first, it would be extremely tense and full of suspicion. Harry would be very wary of Voldemort's motives for protecting him. Voldemort, on the other hand, might be impatient with Harry's lack of trust.
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.
The relationship may develop through a series of challenges. For example, they might face opposition from both the Death Eaters and the Order of the Phoenix. This external pressure forces them to rely on each other more. Fem Harry uses her intelligence and courage to help Voldemort face his inner demons, and Voldemort uses his power to protect Fem Harry from those who want to harm her. Through these shared experiences, their relationship deepens and evolves into a loving marriage.
At first, it would probably be very tense. Harry would be suspicious of Voldemort's motives, and Voldemort would be cautious of Harry's potential to rebel. But as time goes on, they might develop a strange sort of understanding. Harry could start to see Voldemort as more than just a pure evil figure, and Voldemort might start to view Harry as something more than an enemy.
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.
One possible plot could be that Harry is under a spell that makes him believe he loves Voldemort and thus sends the love letters. This spell could be part of a larger plan by some dark wizard who wants to use Harry to get close to Voldemort and manipulate him. Another plot might be that Harry is actually trying to trick Voldemort with the love letters. He could be pretending to have feelings in order to lower Voldemort's guard and find a weakness in him.
The relationship could develop through shared experiences. Maybe they have to face a new common enemy together. This would force them to rely on each other, and in the process, they start to respect each other's skills. Harry's courage and Voldemort's strategic mind could work well together in combat. As they spend more time together, feelings other than hatred might start to emerge, like a strange form of friendship or even more complex emotions.