Maybe an external threat forces them to work together. For example, a dark wizard who targets both the wizarding and Muggle worlds. Harry and Dudley realize that they need to combine their knowledge - Harry's of the wizarding world and Dudley's of the Muggle world - to stop this threat. As they spend time planning and fighting this threat, they start to understand and respect each other more, thus becoming friends.
One possible plot twist could be that Dudley discovers he has some latent magical ability. This would completely change their dynamic as Dudley has always been the 'Muggle' bully. It could lead to him having to rely on Harry for guidance in the wizarding world, which in turn would force them to become friends as they navigate this new situation together.
A plot twist could be that they find out they are related in a more unexpected way than just cousins. This revelation could make Dudley see Harry in a new light and make him more interested in getting to know Harry better. And for Harry, it could make him more empathetic towards Dudley. As they explore this new aspect of their relationship, they gradually become friends.
One possible plot twist could be that Sakura has to face a powerful enemy from her past who tries to stop her from becoming Hokage. Maybe an old rival who has a grudge against her and tries to frame her for a crime in the village. This would force her to prove her innocence while also preparing for the Hokage duties.
In this fanfiction, it could be that Naruto is found to be a prince of a foreign land during one of his missions. As a prince, he is expected to marry for political alliances. However, Naruto is torn between his duties as a prince and his feelings for his friends back in Konoha. He has to find a way to balance both worlds and maybe even change the traditional ways of the foreign kingdom.
One possible plot twist could be that Naruto's transformation into the Juubi is not complete. He might retain some of his human emotions and use them to control the immense power. For example, instead of going on a rampage like a mindless beast, he tries to communicate with the other characters using his new form. He could show that the Juubi's power can be harnessed for good, and that it doesn't have to be a symbol of destruction.
It could develop after a major event changes Dudley's perspective. Say, Dudley witnesses the true extent of the danger Harry faces in the wizarding world. This could make him feel protective of Harry. He might start to defend Harry against their parents' unfair treatment. And Harry, seeing Dudley's change, would be more open to being friends. They could then start to communicate more, sharing their hopes and fears, and slowly but surely, a friendship would form.
A plot twist could be that Dudley has some latent magical ability that is awakened when he is in a life - or - death situation with Piers. This would completely change their relationship with Harry as now Dudley is also part of the magical world in a way.
One possible plot twist could be that Naruto has to face a powerful enemy from within the village who doesn't want him as Hokage. This internal conflict would add a new layer of drama. Another could be that Naruto discovers a long - lost jutsu that changes the way he views leadership and his role as Hokage. For example, it might be a jutsu that allows him to communicate with the spirits of past Hokages in a more direct way, getting unique advice on how to lead the village.
Perhaps Naruto, in his role as the overlord, uncovers a long - hidden conspiracy within the ninja clans. This could involve some clans having secretly worked against others for generations. As a result, he has to use his new - found power and influence to bring about a new era of peace and cooperation among the clans, which is full of challenges and resistance.
One possible plot twist could be that Naruto has to face an unexpected enemy from the past of the Fourth Hokage. Maybe a hidden group that was against Minato's policies and now they see Naruto as a threat. Another could be that Naruto discovers a new jutsu that Minato was developing but never completed, which changes the power dynamics in the village.
Sure. Fanfiction often takes the existing characters and situations and twists them. For Harry and Dudley, it could start with a shared experience that makes Dudley realize Harry isn't so bad. Maybe they get caught up in a magical adventure together outside of the normal Hogwarts - related stuff. This common experience could break down the barriers between them and start a friendship.
Well, if Harry and Dudley became friends, it would drastically change the whole dynamic of the early Harry Potter story. For one, Harry might not have felt so alone at the Dursleys' place. Dudley could have protected Harry from Vernon's wrath. Also, they could have shared secrets about the wizarding world with Dudley being a Muggle. This new friendship might even have led to Dudley developing an understanding and acceptance of the magical world much earlier, and perhaps he could have been an ally to Harry in the fight against Voldemort, instead of a bully.