Longing. Naruto might be cooking for Sasuke because he misses the old Sasuke, the one he grew up with. His cooking is an attempt to bring back that connection, and there's a sense of yearning for the past and for the relationship they once had.
Love. It could be platonic love where Naruto's cooking is an expression of his deep friendship for Sasuke.
Well, it could be about Naruto wanting to show his care for Sasuke through cooking. Maybe he tries to make Sasuke's favorite dishes to bring back old memories and re - kindle their friendship.
Another theme could be about breaking boundaries. In the Naruto world, there are many social and personal boundaries. A fanfiction might explore how Sasuke and Naruto, who are from different backgrounds and have different personalities, cross those boundaries to form a unique relationship. But again, this should be in a non - adult, positive way that respects the original spirit of the series.
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.
One possible theme could be about Naruto trying to break through Sasuke's cold exterior. Maybe Naruto's actions are so intense that it 'wreaks' Sasuke's carefully constructed emotional barriers.
It might be for Naruto's own good. Sasuke may believe that Naruto is on a dangerous path that will lead to his downfall. So he captures him to keep him from making bad decisions, like sacrificing himself for the village or something similar. He wants to save Naruto from himself in a sense.
Well, obviously the adult and inappropriate themes should be avoided. Fanfiction should be more about exploring the relationship in a positive and healthy way. Themes like excessive sexualization are not suitable.
It could also be due to a misunderstanding. Perhaps there is some misinformation spread about Sasuke in the fanfiction, like false rumors that he has a hidden and malevolent plan. Naruto, being someone who values their friendship deeply, would be scared at the thought of Sasuke turning into an enemy because of these untrue stories.
There could be moments of frustration for Naruto, especially when Sasuke is fussy or won't do what Naruto wants him to. But Naruto's love for Sasuke would override that. Emotionally, Naruto would be pouring all his love into taking care of Sasuke, trying to give him the family he never had. And Sasuke, even as a baby, might show signs of his future strong - willed self, which could both amuse and challenge Naruto.
One reason could be Sasuke's thirst for power. If he believes Naruto is the only obstacle in his path to ultimate power, he might be driven to kill him. In some fanfictions, Sasuke may be influenced by a dark entity that twists his mind into thinking Naruto is a threat that needs to be eliminated.
One common theme is redemption. Sasuke has done a lot of things that some might consider wrong, and in many fanfictions, Naruto is the key to his redemption. Another theme is friendship. Their bond is often explored in different ways, like how they support each other in tough times. Also, the idea of power and how they use it together or against each other can be a theme.