Well, one possibility could be that he is forced to join them under some kind of dark magic threat. Maybe Voldemort has found a way to control his mind and he has no choice but to follow their orders. This would lead to a lot of internal conflict for Harry as he struggles with his own values.
The Order of the Phoenix would see Harry's joining of the Death Eaters as a major setback. They would likely view it as a sign that Voldemort has become even more powerful. Dumbledore, if he were still alive, would be very concerned and would try to understand what led Harry to this decision. He would also be devising a plan to get Harry out of the clutches of the Death Eaters.
Well, perhaps in this fanfiction, there's a big misunderstanding. Harry might think that by infiltrating the Death Eaters as one of them, he can actually bring them down from the inside. So he pretends to join them, but things get out of hand as he has to constantly prove his loyalty to the dark side, which is really difficult for him.
Well, if we look at 'Harry Joins Death Eaters Fanfic', it could lead to a whole new set of storylines. Harry might be lured in by the power the Death Eaters seem to have. He could start using dark magic, and his moral compass would be all messed up. Maybe he'd be used by Voldemort to infiltrate the Order of the Phoenix from the inside. It would be a very different Harry, one who has lost his way and is now on the side of evil.
The Hogwarts students would be divided. Some would be in disbelief and would still hope that Harry has a good reason for joining. They might secretly support him. Others, especially those who have lost family members to the Death Eaters, would be furious and see Harry as a traitor. Harry's old enemies at Hogwarts, like Draco Malfoy, would also be confused. Draco might initially think that Harry has finally seen the 'right' side, but as he realizes Harry's true intentions (if they are good), he would be conflicted as well since he's been brought up in a Death Eater - influenced family.
Definitely. Some fanfictions depict Harry Potter's attempts to infiltrate the Death Eater ranks or gather intelligence on them. This creates exciting storylines that revolve around mystery, danger, and the fight between good and evil in the Harry Potter universe, all while keeping the content suitable for a wide range of readers.
A possible motive could be self - preservation. If they believe that Voldemort's downfall is inevitable and that by saving Harry, they can gain some form of leniency from the side that opposes Voldemort. They might think that Harry has enough influence to spare their lives if they help him.
The wizarding world would be in shock. Harry was seen as the 'Chosen One' to defeat Voldemort. If he joined the Death Eaters, the Order of the Phoenix would feel betrayed. They might try to rescue him or think he's been an undercover agent all along. Hogwarts would be in chaos, and students would be confused and scared.
Voldemort himself, of course, is the most prominent in a sense. But in the fanfiction, his relationship with the other Death Eaters could be different. He might be more distrustful or have different expectations of them. And then there's Barty Crouch Jr. He could be a major player in the fanfiction, with his skills in disguise and dark magic. His actions could drive some of the major plotlines in the fanfiction.
One great fanfiction is 'The Battle Against the Dark'. In this story, Harry Potter uses some unique spells he learned from an old wizard to combat the Death Eaters. The fight scenes are really intense and it shows Harry's growth as a wizard. It also has some interesting plot twists that keep you hooked.