The Death Eaters would have a mixed reaction. Some might see Harry as a potential ally, thinking that his dark necromancy powers could be used to their advantage. Others, especially the more loyal to Voldemort's pureblood ideology, would see Harry as an abomination, as he was once the 'Chosen One' and now is using a form of magic that they consider unclean. The other students at Hogwarts would be mostly afraid, but a few might be intrigued and form a sort of 'underground' following of Harry's new powers.
Dumbledore, if he were still alive, would be very cautious. He would try to guide Harry towards using his powers for good, or at least in a way that doesn't disrupt the balance of the wizarding world. The other Hogwarts professors would likely be split. Some would be horrified and want to expel Harry, while others would see it as an opportunity to study a rare form of magic and its implications.
Hermione would be devastated. She has always been Harry's loyal friend and believed in the fight against the Dark Lord. She would probably try to convince Harry to come back to the right side, reasoning with him about the evil nature of the Dark Lord's actions. Ron, on the other hand, would be both angry and confused. He might initially think it's some sort of joke or that Harry has been tricked.
Harry Potter would likely be on high alert immediately. He has experience with fighting Dark Lords, so he would start gathering his old friends and allies. Hermione would be researching like mad, trying to find any weaknesses of this new Dark Lord. Ron would be a bit more hesitant at first but would soon join the fight. The younger generation, like Ginny and Neville's students, would be both scared and determined to prove themselves in the face of this new threat.
The teachers at Hogwarts, like Dumbledore (if he were still alive in the fanfic), would be deeply concerned. Dumbledore always saw great potential in Harry for good. He would probably try to understand what led Harry to this path and would use all his wisdom and magic to try and turn Harry back. The other teachers would also be on high alert, fearing for the safety of the students and the future of the wizarding world.
Ron would be devastated. He's been their best friend for years. He'd probably try to talk them out of it at first. If that fails, he might have to choose between loyalty to his friends and what he believes is right. The Hogwarts professors, like Dumbledore (if he were still alive in the fanfiction), would be very concerned. Dumbledore would likely see it as a great loss of two of the brightest lights in the wizarding world. He might try to find a way to reverse whatever led them down this dark path.
One idea could be Harry, as a dark necromancer, using his newfound powers to bring back some of the great wizards from the past to learn from them, but the magic has unforeseen consequences like attracting dark entities. Another could be that he's on a quest to revive a loved one, which goes against the natural order of magic in the wizarding world and causes a rift between him and his friends.
One example could be a fan - created character who is a dark seer. She uses her powers not for the good of the wizarding world but for her own gain, yet she has a certain allure. Another could be a version of Hermione where she delves into some of the darker aspects of magic in a bid to outwit Voldemort in a different way.
The characters in the 'dark trio' in the fanfiction are likely to be those who have a propensity for the dark arts or have some sort of malicious intent. It could be that the author takes minor characters from the original series and gives them more prominent roles within this dark context. For example, Crabbe and Goyle could be developed further into more menacing characters, or perhaps some of the Death Eaters that were not as well - explored in the original books could be part of this trio.
No. Harry Potter is a mainstream fantasy series created by J.K. Rowling. It has a well - developed magical world, themes of friendship, courage, and good versus evil. The story follows the adventures of Harry and his friends at Hogwarts. Fanfiction might exist that takes a 'dark' turn on the original concept, but the original work is not dark fanfiction.
In some fanfiction, Harry Potter can be portrayed as 'dark' and a 'bearer' in very different interpretations from the original series. Fanfic authors often like to explore alternative character arcs and personalities.
Alliances play a crucial role. Characters can band together to resist dark rituals. They can combine their magic powers and skills. For example, a group of students from different houses at Hogwarts might join forces. One could use their knowledge of ancient runes, another their skills in defensive magic, and yet another their ability to think quickly on their feet to prevent a dark ritual from being carried out on the school grounds.