In the fanfic, it could be that Sasuke has been possessed by an ancient evil force. Naruto, being the only one powerful enough to face him, steps up. He first tries to understand what has happened to Sasuke. But when he realizes that there's no other way, he uses his most powerful form, like the Six Paths Sage Mode. He battles Sasuke all over the elemental nations. During the fight, Naruto breaks through Sasuke's defenses and destroys the evil within Sasuke. This could lead to Sasuke being reborn in a sense, free from the evil influence, but also weakened, and Naruto then has to help him regain his strength and purpose in a post - battle world.
Maybe in this fanfic, Sasuke has gone too far in his quest for power and revenge. He starts attacking innocent people or trying to take over the Hidden Leaf Village. Naruto, as the hero, has no choice but to stop him. Naruto could use his talk - no - jutsu at first, but when that fails, he resorts to physical combat. He might start with his basic Rasengan and gradually level up his attacks as Sasuke counters with his Chidori and other powerful jutsus. In the end, Naruto destroys Sasuke's evil intentions and either kills him or imprisons him, depending on the tone of the fanfic.
One possible plotline could be that Naruto, having a fundamental difference in ideology with Sasuke, decides to take a stand. Maybe Sasuke is on a path that Naruto believes will destroy the village or their friends. So Naruto uses his newfound powers, perhaps a combination of Sage Mode and Nine - Tails chakra, to directly confront Sasuke. Naruto could try to break Sasuke's resolve through sheer force and the power of their friendship memories.
One possible plotline could be that Naruto has a sudden and extreme power-up that makes him overconfident. This overconfidence leads him to challenge Neji in a spar that gets out of hand and he ends up 'destroying' Neji in the sense of completely overpowering him. Maybe Naruto has unlocked a new form of his chakra that Neji can't counter with his Gentle Fist technique.
One possible theme could be revenge. If the writer is bashing Sasuke, they might have Naruto seek revenge on Sasuke for his actions in the original story, like when Sasuke left the village. Another theme could be power display, showing Naruto's overwhelming power as he destroys Sasuke.
In some fanfics, it could be a situation where they are trying to save the ninja world from a great disaster. They end up using a powerful jutsu that requires both of their life forces. They know that this jutsu will kill them, but they are willing to sacrifice themselves for the greater good. As they perform the jutsu, they share memories of their past, their rivalry, and their friendship, and then they die together, leaving behind a world that they have saved.
Yes, there might be such fanfics out there. In the Naruto fandom, with a large number of fans creating various types of stories, it's possible that some would write a story where Naruto destroys Sasuke in a way that could be seen as Sasuke - bashing. However, these kinds of fanfics may not be in line with the overall spirit of the original work which focuses on their complex relationship and growth.
One possible plotline could be a comical situation where Sasuke is exasperated with Naruto's silly behavior and decides to 'spank' him as a form of discipline in a very light - hearted and friendly way. It could be part of their banter and growth as friends.
In a fanfic with a female Sasuke, the plotline might include her using her femininity as a strength in the ninja world. She could be more in tune with nature - based jutsu, for instance, and use that to her advantage. Her journey could also involve breaking gender barriers in the Hidden Leaf Village. She might be the first female to attempt certain high - level ninja training or missions. And her relationships with other characters like Sakura could be more complex, with a mix of competition and sisterly support as they both strive to be great ninjas in their own ways.
One possible plotline could be that Naruto is somehow corrupted or misled. Maybe he discovers some dark secrets within Konoha that he believes can only be resolved by its destruction. As for the Alvarez Empire, they might see an opportunity to expand their influence in the chaos Naruto creates and form an uneasy alliance with him at first.
Maybe Sakura teaches Sasuke about emotional control. Sasuke has always been brooding and angry, and Sakura, with her more empathetic nature, could show him how to manage his emotions better. This could lead to Sasuke becoming a more well - rounded ninja and a better teammate.
Maybe Sasuke is jealous because Sakura has achieved some great feat in the ninja world and is getting a lot of attention. In the fanfic, this could lead to Sasuke training even harder to prove himself worthy of her. Sakura, on the other hand, might be confused by Sasuke's sudden distance. She could try to reach out to him, but Sasuke's pride and jealousy keep him from being receptive. It could all come to a head during a dangerous encounter with a powerful enemy where they finally communicate their feelings.