In some rey turns to the dark side fanfiction, it could be due to a betrayal. For example, if she feels that her friends in the Resistance have let her down or used her. This sense of abandonment and being used could drive her to seek power from the dark side. She might then start to oppose her former allies and cause chaos within the galaxy.
Another plotline could involve the influence of a dark side user. A powerful Sith Lord or a dark side entity could start to whisper in Rey's ear, tempting her with knowledge and power that she can't resist. As she delves deeper into this dark knowledge, she gradually turns away from the light side and embraces the dark.
One possible plotline could be Rey being influenced by a powerful dark side artifact. Maybe she discovers an ancient Sith relic that slowly corrupts her mind and turns her to the dark side. She starts to have different views on power and the Force, believing that the ends justify the means.
In some rey falls to the dark side fanfiction, her turn could be due to a sense of betrayal. If she discovers some dark secrets about the Jedi Order or the Resistance, she might feel that the dark side is the only way to get true justice. For instance, if she finds out that the Jedi had some hidden, unethical practices in the past. Then she starts to embrace the dark side teachings and uses her powers in a more aggressive and self - serving way.
Obviously Rey herself is the central character. Kylo Ren often plays a role too. In some fanfictions, he might be the one who either tries to stop her from fully turning to the dark side because he has some sort of connection with her, or he might be the one who encourages her to embrace the dark side to be with him.
The consequences would be huge. The Resistance would lose one of its most powerful allies. It would also mean a new threat to the galaxy. Rey's turn to the Dark Side could inspire others to follow her, leading to a resurgence of the Sith. The balance of the Force would be severely disrupted.
One possible plotline could be that Harry is influenced by a dark artifact. For example, he discovers a cursed object that slowly corrupts his mind, making him turn against his friends. He might start to use dark magic to achieve his goals, believing that the end justifies the means.
If Rey turns to the Dark Side in fanfiction, one possibility is that she becomes a powerful and feared Sith. She might use her newfound dark powers to seek revenge on those who she believes have wronged her in the past. Maybe she would target the Resistance, seeing them as the ones who failed to fully understand or support her. Her connection to the Force could take a dark turn, with her using it for domination rather than protection.
Some fanfictions explore Anakin's turn from the perspective of his friendship with Obi - Wan. Maybe there's a rift between them caused by outside forces, like a false accusation against Anakin that Obi - Wan doesn't fully believe him about. This slowly sours their relationship and Anakin, feeling abandoned by his friend, is more susceptible to the dark side's allure.
One possible plotline could be that Rey finally succumbs to the dark side under Kylo Ren's influence. He might train her in the ways of the dark side, leading them to rule the galaxy together with an iron fist. Maybe they start by taking over the First Order and using its resources to spread fear and chaos.
It could be the remaining Jedi. Since Rey is turning, the Jedi who still uphold the light side would see her as a threat. They would try to stop her from causing more harm with her newfound dark side powers.
One idea could be Rey being lured to the dark side by a powerful Sith artifact. Maybe she discovers an ancient Sith holocron that shows her a version of the galaxy where the dark side rules supreme and she starts to believe that it's the only way to bring true order. Another plot could involve Rey being manipulated by a dark side user who preys on her insecurities about her past and her power.
One possible plotline could be Windu's internal struggle as he is gradually lured to the dark side. Maybe he starts to question the Jedi Code more and more as he experiences certain events or is influenced by a powerful dark side figure.