The most obvious ones are Edward and Jacob. Edward, as Bella's vampire lover, will have to deal with a Bella who is no longer the same person he fell in love with. He will struggle to understand her new actions and motives. Jacob, on the other hand, will see his relationship with Bella, which was already complicated, become even more so. Additionally, the Cullen family as a whole will be affected. They have accepted Bella into their family, and now they have to face this new, unpredictable Bella.
First off, Edward is likely to be deeply affected. He has spent so much time and energy trying to protect Bella and keep her safe. Now, with her humanity off, he may feel like he has failed. Jacob, too, will be affected. His feelings for Bella, whether it's love or friendship, will be challenged. Also, Bella's father would be affected. He has always cared for his daughter, and seeing her change so drastically would be heart - breaking for him.
In this kind of fanfiction, the plot might involve Bella becoming a more ruthless and self - centered character. She may no longer be bound by her usual moral and emotional constraints. For example, she could start to disregard the feelings of her friends and family. She might also engage in more dangerous or unpredictable behavior, like getting involved with the wrong crowd in the vampire or werewolf world.
Obviously, Edward would be deeply impacted. He has dedicated himself to Bella, and her new evil nature would force him to reevaluate their relationship. Jacob, who has always been in the mix with Bella, would face a great deal of turmoil. And don't forget Carlisle and the rest of the Cullen family. They have accepted Bella into their family, and her going evil would be a major threat to their way of life and their values.
Bella, obviously. She is the one who is pregnant and will have to face all the physical and emotional changes that come with it. Her life will be completely turned around as she prepares to be a mother.
The main characters Damon and Bella will interact with each other on multiple levels. Damon will probably teach Bella about the vampire way of life. There could be other vampires from different clans that cross their path. These vampires might be curious about Bella or have their own agendas. Additionally, if the fanfiction has a touch of the supernatural world at large, angels or demons (if they exist in that universe) could also interact with them, adding a whole new layer of complexity to the story.
Obviously, Harry's closest friends like Hermione and Ron. They would be devastated. Hermione would probably be racked with guilt for not being able to prevent it. Ron would be angry and at the same time lost without his best friend.
Well, he might become more ruthless. He could start making decisions without the normal moral compass that his humanity provides. For example, he might be more willing to use extreme violence to achieve his goals, not caring about the harm it causes to others.
Well, Mary Jane would be one of the most affected. She has a deep emotional connection with Spider - Man. Ned, his friend from school, would be lost without him. And then there's J. Jonah Jameson. Even though he's often against Spider - Man, he might feel a strange sense of loss. Also, any villains who had a sort of twisted relationship with Spider - Man might also be affected in some way, like Venom or Green Goblin.
The other students at Hogwarts would also be affected. For example, Neville, who looks up to Harry. If Harry ignores everyone, Neville might feel lost. Ginny, who has a special connection with Harry, would be deeply hurt. And the teachers like Snape, who has a complex relationship with Harry, would also be impacted. Snape might be secretly glad at first, but then realize that Harry's isolation could be a sign of a bigger problem in the wizarding world.
Family members, if he has any in the fanfiction world, would be devastated. His mother, for instance, would have to deal with the loss of her son. She might become more involved in the affairs of the demigod world, trying to make sure that her son's sacrifice was not in vain. Also, his half - siblings, if any, would be affected. They could be inspired to step up and prove themselves worthy of Percy's sacrifice.
The Death Eaters themselves would be affected in an interesting way. Some might welcome Harry with open arms, but others might be suspicious of his sudden change of sides. They might fear that it's a trick by the Order. And within Hogwarts, the students would be in turmoil. Those who idolized Harry would be heartbroken and confused, and there could be a split among the student body depending on who believes Harry's new stance.