Well, in the fanfiction, a likely plot development is that Naruto's newfound power, perhaps a unique form of Rasengan, is crucial in the fight against Itachi. Sasuke, on the other hand, is initially blinded by revenge but Naruto helps him see that there's more to Itachi's actions. This could lead to a situation where they don't actually kill Itachi but rather free him from whatever binds him to his 'evil' deeds. The fanfic might then explore how they deal with the consequences of not following through with the kill.
Their relationship could become more complex. On one hand, they have achieved their goal together, but on the other, Sasuke might feel guilty for killing his brother with Naruto's help. Naruto, in turn, might worry that Sasuke will go back to his old ways. So, while they have this new connection, there could also be new tensions and insecurities in their relationship.
One possible plot twist could be that Naruto, after learning more about Itachi's sacrifices for the village, starts to idolize him in a way that changes his own ninja path. He might adopt some of Itachi's stealthy and strategic techniques. For example, he could focus more on gathering intelligence before acting, rather than his usual head - on approach.
Another plot twist could be that an enemy uses their relationship against them. The enemy could spread rumors or false information to create chaos and turn the ninja world against them. Naruto and Sasuke would then have to fight not only to protect their relationship but also to clear their names and prove that their love doesn't mean harm to the ninja world.
Well, a great plot twist could be that Akatsuki is actually being controlled by a greater evil force that neither Naruto nor Itachi knew about. When they join, they start to notice strange behavior among the members that doesn't seem to align with the original goals of Akatsuki. Naruto, with his unwavering belief in friendship and Itachi's strategic mind, might then team up to expose this greater threat and save the ninja world. It would also be interesting if their joining Akatsuki causes a rift among the members, some seeing them as potential allies and others as enemies.
One possible plot twist could be that Naruto, while modeled after Itachi, has to face off against Sasuke who mistakes him for Itachi at first. This would create a really tense and emotional situation as Sasuke's hatred for Itachi might be misdirected towards Naruto.
One possible plot twist could be that their marriage causes a rift in the ninja world. Some might oppose it due to Itachi's past actions. Another could be that they discover a new power that comes with their union, which is crucial in saving the world from a new threat. And perhaps they have to deal with family issues, like Naruto trying to make Itachi feel welcome in Konoha despite his past.
One interesting plot twist could be that Itachi has a hidden motive that is actually to protect Sasuke from a greater threat. Maybe there's a powerful enemy that Itachi knows will target Sasuke, so he kidnaps him to keep him in a secret location and train him in secret. Another twist could be that Itachi is being controlled by some dark jutsu and he doesn't really want to kidnap Sasuke but has no choice. This could lead to a journey of Sasuke trying to break the control over Itachi. Also, it could be that Itachi kidnaps Sasuke to reveal some long - hidden family secrets that Sasuke needs to know in order to become stronger.
One plot twist could be that they find out a traitor in Suna who is secretly working for an enemy of both Konoha and Suna. This would put them in a difficult situation as they have to figure out who to trust.
One possible plot twist could be that Sasuke has been under a genjutsu that makes him target Sakura, and Naruto has to break the genjutsu first to truly save her. Maybe the one who cast the genjutsu is a new, powerful enemy who wants to disrupt the bond between Team 7. Naruto, with his strong will and newfound powers, manages to find the source of the genjutsu and free Sasuke from its control, thus saving Sakura from harm.
A plot twist might be that Naruto and Sasuke discover a hidden agenda Orochimaru has that involves someone they care about deeply. For example, they find out he's planning to use Sakura as a sacrifice for some dark ritual. This would force them to quickly come up with a plan to rescue her and stop Orochimaru once and for all.