Daphne could be a fictional character created specifically for this fanfic. She might be a witch from a well - known wizarding family. Maybe she's a classmate of Harry's at Hogwarts or someone who has just heard about his situation and feels compelled to help.
The main characters are obviously Harry and Daphne. Harry, the well - known hero from the Harry Potter series, is the one who does the saving. Daphne is the one in need of rescue from the Dementors.
Well, in this fanfiction, it could start with Daphne being targeted by the Dementors for some specific reason. Maybe she has some information that the dark forces associated with the Dementors don't want her to spread. Harry, being the hero he is, just happens to be in the right place at the right time. He quickly conjures his Patronus, which is a stag, and it chases away the Dementors. Daphne is grateful and from that moment on, she becomes more involved in Harry's fight against the dark arts, and they form a strong alliance.
Well, it could be that Daphne is in danger during a dark wizard attack at Hogwarts. Harry, being the hero he is, uses his skills and magic to fend off the attackers and save her. Maybe she was in the wrong place at the wrong time near the Forbidden Forest.
Dark wizards or witches who are on a power - hungry spree could be the antagonists. They might see Daphne as an easy target or a way to get to Harry Potter himself. So they kidnap her to lure Harry into a trap.
It could be some dark wizards who are not part of the Death Eaters but are still up to no good. They might see Daphne as an easy target during the busy and chaotic World Cup. They could be after her family's wealth or some magical artifact she might be carrying.
Well, perhaps there is some sort of magical accident at the World Cup. A spell goes wrong and endangers Daphne. Harry, being the hero he is, senses the danger and manages to counter the spell just in time. He might use his knowledge of defensive magic, which he has learned from his years at Hogwarts, to keep Daphne safe from the harmful effects of the misfired spell.
A common plotline is that Daphne saves Harry from a dark magic attack. For example, she might notice a cursed object meant for Harry and intervenes just in time.
There could be a 'Harry Saves Daphne' fanfic where Harry saves Daphne from a group of dark wizards. This event changes Daphne's view of Harry completely, and she starts to see him in a new light, perhaps even developing feelings for him. The story then follows their adventures together as they face new threats in the wizarding world.
Well, Harry might save Daphne from Draco because Harry is always the hero type. He doesn't like Draco's pure - blood supremacist attitude. Daphne could be a target of Draco's cruel remarks or actions just because she might not fully conform to Draco's ideas. Harry, being the defender of the underdog in many cases, steps in. Also, it could be that the plot of the fanfiction is building a new alliance or relationship web, and Harry saving Daphne is a key part of that, leading to new story developments.