Harry Potter would likely be one of the main characters. Since Ginny is his love interest in the original series, he would surely be affected by her marriage to Voldemort. He might be the one to try and rescue her or stop the marriage. Ron Weasley, Ginny's brother, would also be important. He would be outraged and would probably be part of any plan to oppose the union.
In some fanfictions, Hermione might use her wits to try and outsmart Voldemort. For example, she could pretend to be on his side while secretly planning an escape or a way to undermine his plans. She's very intelligent, so she could try to find a weakness in Voldemort's defenses or his followers.
Ginny often reacts with defiance. She's a strong - willed character. So, she might fight back against Dark Harry, both physically and verbally. She could try to escape at every opportunity, using her knowledge of magic to her advantage.
Well, it could be out of jealousy. Maybe Dean feels like he's losing Ginny to someone else and in a moment of madness, decides to kidnap her. But this is all just speculation within the wild world of fanfiction.
This is a really interesting and dark fanfiction concept. In the Harry Potter universe, Draco and Ginny are from different houses and have different loyalties. If Draco were to kidnap Ginny to marry her, it would go against her will and the values of the wizarding world. However, it could make for a very intense and dramatic story, exploring themes of power, love, and coercion.
One possible plot could be that Harry is under the influence of a dark spell or some mind - controlling magic that makes him kidnap Ginny. Maybe he's been hexed by a powerful dark wizard who wants to use Ginny as a bargaining chip against the Order of Phoenix. So, Harry, without his true self in control, takes Ginny to a hidden location.
Harry could also try to reason with Voldemort. He might remind Voldemort of the prophecies and how killing him might not be in Voldemort's best interest. He could also try to appeal to any bit of humanity that might still be left in Voldemort, although that's a long shot.
In some fanfictions, the focus could shift to Hermione's internal struggle. She might be forced to relive some of her worst memories or face her fears because of Voldemort's dark magic. However, this could also be the moment when she discovers new powers or strengths within herself that she didn't know she had, which she could then use to escape or fight back.
In many such fanfictions, there could be a lot of different scenarios. One possibility is that the wizarding world would be in chaos. Dumbledore might lead a frantic search for baby Harry. Maybe some of the Order of the Phoenix members would try to infiltrate Voldemort's lair to rescue him. It could also be that Voldemort has some strange plan for Harry, like trying to turn him to the dark side from a very young age.
One popular fanfic could be 'The Dark Lord's Captive' where Hermione is kidnapped by Voldemort and she uses her intelligence to outwit him in unexpected ways. Another might be 'Hermione in the Dark Lord's Lair' which focuses on her psychological struggle while being held captive.