One way could be through dark magic coercion. Maybe Voldemort uses some powerful dark spell to force Daphne into this hand - fasting. Another possibility is that Daphne's family has some sort of dark secret or debt to Voldemort, and she is sacrificed in a way through this hand - fasting. But this would be a very dark and disturbing plotline in fanfiction.
In Harry Potter fanfiction, while it's an extremely unusual concept, it could potentially be possible in the realm of creative writing. However, Daphne is a Slytherin student and Voldemort is the ultimate dark lord. Their alliance in a hand - fasting (a form of betrothal or union) would be a very dark and unorthodox take. It would likely involve a lot of creative liberties with the existing lore, as Voldemort is mainly focused on domination and immortality, not on traditional relationships.
There are not many fanfictions that would combine Daphne, Voldemort and Harry in the context of handfasting in a traditional sense. Handfasting is often associated with a form of magical binding or marriage - like ceremony in the wizarding world in fanfiction. However, if it exists, it would likely be a very dark and complex story. Maybe Daphne could be caught in the middle of the eternal battle between Harry and Voldemort, and the handfasting could be some sort of dark ritual Voldemort forces upon them. But this is all speculation as it's not a common or typical fanfiction trope.
Harry's family situation is a bit complex. His friends from Hogwarts could be like his family too. They might be initially surprised by his choice but come to support him. Daphne's family, being a pure - blood Slytherin family, might have some reservations at first. But as they see Harry's character and how much he cares for Daphne, they warm up to the idea. For example, Daphne's parents could see Harry as a way to bridge the gap between the different wizarding ideologies.
In this fanfiction, it could be that Voldemort has a premonition. He sees that if Harry Potter dies, it will lead to a series of disasters that will also destroy his own plans. So, in order to preserve the balance or to keep his long - term goals intact, he saves Harry. For example, if Harry's death causes an uncontrollable chaos in the wizarding world, Voldemort's rule over the dark forces might be disrupted. So he steps in to save Harry.
In fanfiction, a stuck Animagus Harry Potter might have to rely on his friends more. Hermione could research ways to break the Animagus 'stuck' state while Ron could try to distract Voldemort. Harry in his animal form could also try to find some magical artifacts or secrets that could be used against Voldemort. For example, if he was a bird Animagus, he could fly to hidden places that might hold the key to defeating Voldemort.
Well, one way could be through some dark and misinterpreted magic. Maybe Harry stumbles upon an ancient spell that he thinks will defeat Voldemort once and for all but instead, it backfires and revives him. It could also be due to some sort of interference from a powerful dark object that Harry unknowingly uses in the wrong way.
Their relationship could develop through shared adventure. As they explore the secrets of the Potter ring together, they start to rely on each other more. Harry sees Daphne's intelligence and resourcefulness, and Daphne sees Harry's courage. This mutual respect gradually turns into a deeper friendship and perhaps something more romantic.
Hermione could be involved. She might suspect Daphne of having ulterior motives regarding Harry and try to warn him, which could play into the betrayal storyline in some way, either as a catalyst or as someone who helps Harry deal with the betrayal later.
In fanfiction, Harry Potter and Voldemort are related through the prophecy that ties their fates together. This often leads to scenarios where Harry has a unique understanding of Voldemort, like being able to see into his mind. Fanfic writers may also play with the idea of a shared past or some sort of magical bond that was created before they even knew of each other. They are two sides of a magical coin in many fanfictions, with Harry representing the good and Voldemort the evil, but their relationship is much more nuanced than just that.
Theodore Nott could be another main character. He might be a friend of Daphne or her future husband. In the fanfiction, he could be involved in the events leading up to the marriage, like helping with the preparations or being part of a sub - plot where he has his own feelings or motives regarding the marriage. Additionally, Luna Lovegood could make an appearance, adding her unique perspective to the story and perhaps being a friend to Daphne during this important time.