They might justify it through her past traumas. For instance, if Sakura has faced repeated rejections or has been constantly overshadowed in the original story, a writer could use this as a reason for her to betray. She could feel that she has been treated unfairly and that her so - called friends never really understood her pain. So, in the fanfiction, she decides to take a different path that is seen as a betrayal to those around her.
Writers may also justify Sakura's betrayal in fanfiction by giving her new relationships. If she forms a deep bond with a new character who has different beliefs or goals, she might be influenced to turn her back on her old friends. This new relationship could offer her something she has always desired, like acceptance or a sense of purpose that she didn't feel in her previous relationships, leading to her betrayal.
Another way of justifying her betrayal is by showing a different side of the world she lives in. If the fanfiction reveals a more complex political landscape where the village she belongs to is not as noble as it seems, Sakura could be portrayed as someone who betrays to fight for a greater justice. Maybe she discovers that the village has been involved in immoral activities, and she takes a stand against it, which is misinterpreted as betrayal by her comrades.
Some authors justify it by giving Sakura a tragic backstory. For instance, if she was always overlooked or mistreated in her village, she might be more likely to be swayed by offers of acceptance from the enemy. It's like she's seeking validation from the wrong place.
One common theme could be her betraying her friends for power. In some fanfictions, Sakura might be lured by the promise of great strength and abandon her comrades. For example, she could be tempted by an enemy who offers her the ability to be the strongest ninja, and she turns against Naruto and Sasuke. Another theme could be a betrayal of love. Maybe she realizes she has feelings for someone other than Sasuke and her actions to pursue this new love are seen as a betrayal to the long - established 'Sakura - Sasuke' relationship in the original story.
Some writers justify it by creating a situation where Sasuke has to make a great sacrifice. For example, he might give his life to protect Naruto or the Hidden Leaf Village from an overwhelming threat. His selfless act in these scenarios is seen as a way to atone for his past mistakes and show his growth as a character.
They might justify it through misunderstandings. Maybe Arthur is tricked into a situation that looks like cheating but he's really trying to protect Merlin in some convoluted way.
Well, often they use the idea of Naruto's strong will. They say that his will is so strong that it breaks the normal limits of what is possible in the Naruto universe. So, his will allows him to access these impossible powers. Also, in some fanfictions, Naruto goes through some extreme and unique training or experiences that no one else has had, and this is what gives him these extraordinary abilities. For example, he might travel to a different dimension where the laws of physics and chakra are different, and when he comes back, he has these new powers.
Some writers might justify it by exploring the idea of redemption. They could write Voldemort in a way that shows a glimmer of humanity that Harry, being abused, might be able to relate to on some level. Maybe Voldemort has a hidden past that makes him more complex than just the evil wizard we know.
Some writers justify it by saying that Harry is a descendant of a powerful ancient magical line that was long forgotten. This hidden heritage unlocks his godlike powers as he grows older and discovers more about his past. For example, he might find out that his ancestors made a pact with some powerful magical beings, and the powers are now passed down to him.
A possible justification could be a deep exploration of Harry's post - traumatic stress. Writers might think that after years of fighting and losing so many people, Harry could reach a breaking point. But really, the Harry Potter we know from the books has a strong will and a support system that should prevent such a tragic end. So, these justifications seem more like attempts to create shock value rather than staying true to the character's nature.
Some writers use the idea of a common enemy. If there is a powerful foe that threatens both Artemis and Percy's worlds, they are forced to team up. During this cooperation, they discover new sides of each other. Percy might show his loyalty and courage in a way that makes Artemis fall for him, and thus the relationship is justified.
Some writers justify it by exploring a deep emotional connection. Maybe Draco has been protecting Harry in the fic, and Harry starts to see him as a paternal figure. For example, if Draco saves Harry from a great danger multiple times, Harry might develop a sense of dependence and respect that could lead to this. Another way is through a magical bond. If there's a spell or a magical accident that links them in a way that Harry feels a child - like connection to Draco, it can be used as a justification.