The wizarding world would be in shock. People who have fought against Bellatrix would be horrified at the thought of her being related to Harry. The Ministry of Magic would likely be very concerned about how this new relationship could impact the balance of power. Some might think it's a ploy by Bellatrix to gain more power, while others might feel sorry for Harry having such a complex family situation.
Well, Bellatrix is a very unpredictable character. In this fanfiction scenario, she could react with glee. Since she's on the side of the Dark Lord, she might think that Harry's abuse has made him more vulnerable. She could also be curious about who would dare to abuse 'the Boy Who Lived'. However, she might also be angry that someone else has been causing harm to Harry when she believes that's her Dark Lord's prerogative.
The wizarding world would be in chaos. The people who have idolized Harry as the Boy Who Lived would be horrified. Many would see him as a potential threat, fearing that he might inherit Bellatrix's cruel and dark nature. The Ministry of Magic would probably put him under intense scrutiny. His friends at Hogwarts, like Neville, might initially be shocked and have a hard time accepting it. But some might also believe that Harry has the strength to rise above his heritage.
In such a fanfiction, Bellatrix might experience a complete shift in her loyalties. She could turn against Voldemort to protect Harry. For example, she might use her position within the Death Eaters to mislead Voldemort about Harry's whereabouts. It would also create a huge stir in the wizarding world, as Bellatrix has been one of Voldemort's most feared and loyal followers. And Harry would have to come to terms with having such a complex and villainous mother figure, which could lead to a lot of internal conflict for him.
Some in the wizarding world might be very accepting. After all, soulmates are considered a special and magical thing. But there could also be those who are more traditional and might not understand how two guys could be soulmates. They might gossip or spread rumors, but the true friends of Harry and Fred would stand by them.
There could be major political implications. In the fanfiction, if Bellatrix reveals Harry's abuse, it might shake the foundation of the Order of the Phoenix. Some members might question Dumbledore's leadership, thinking he should have protected Harry better. Meanwhile, the Death Eaters could use it to gain more followers, painting Harry as a broken hero. This could also lead to changes in how the wizarding world views child protection, with new laws or policies being proposed.
The wizarding community would be quite shocked. Some might feel sorry for Harry, having to deal with such a strange and unexpected revelation. Others might gossip about it endlessly. The Weasley family's reputation might also be affected in some ways. People might view them differently, perhaps with more curiosity about how they didn't know this all along. And for Harry, he might receive more pitying looks from his friends and acquaintances, which he might not like at all.
The wizarding world would be in an uproar. Some would be sympathetic towards Harry, understanding the struggles he had endured. Others might be judgmental, especially those who come from pure - blood families and have different values.
The Gryffindor house would be in an uproar. Her friends and classmates would be desperate to do something. Neville, for example, might step up more than ever, given his own growth in courage. They would likely start by informing the teachers, like McGonagall, who would then take the matter to Dumbledore's Army.
Some might be shocked and feel betrayed. Harry is a hero to many, so his departure could leave them feeling abandoned. Others might understand his need for a break and respect his decision.
The wizarding world would be in chaos. Harry is seen as a hero and the 'Chosen One'. His death would leave a huge void. The Order of the Phoenix would be devastated and might seek revenge on Draco and those associated with him. Hogwarts would also be in turmoil, with students and teachers alike shocked and saddened. There would be a great deal of fear as well, as Voldemort's forces might see this as an opportunity to gain more power.