In such a fanfiction, it could be possible through a dark corruption of Naruto's power. Maybe the Nine - Tails' influence takes over him completely. His powers could go out of control, and with his incredible strength, he might start attacking without restraint, believing that the current world is beyond saving or redemption.
Perhaps they are being manipulated by an outside force. An enemy of Konoha could deceive them into believing that the village is a threat to the greater good. This would lead them to take the drastic step of destruction. For example, if they are shown false evidence of Konoha planning to start a war that would cause mass destruction, they might act to stop it in what they think is the only way - by destroying Konoha.
One possible motive could be a sense of betrayal. Maybe Naruto felt constantly ostracized in Konoha despite his efforts to be accepted, and over time, that bitterness turned into pure hatred. For example, if he was always treated as an outcast by the villagers even after saving them multiple times, it could drive him to destroy the very place that never truly welcomed him.
It could be due to a prophecy misinterpretation. Suppose there is a prophecy that Naruto misinterprets as the Leaf Village needing to be destroyed for the greater good. Or perhaps he is tricked by a very cunning enemy who convinces him that the Leaf Village is the root of all the problems in the ninja world.
Another motive might be related to some sort of dark influence. Suppose Naruto is exposed to an ancient and evil power that corrupts his mind. This power could fill him with hatred towards humanity, making him believe that destroying all humans is the only way to cleanse the world. Like in some stories where dark magic can twist a hero's good intentions.
One possible plotline could be that Naruto discovers a deep conspiracy within Konoha that makes him feel betrayed. For example, he might find out that some of the village elders have been using him all along as a tool to gain power. So in his rage, he decides to take revenge on the village. He could start by using his shadow clones to create chaos and disrupt the normal operations of Konoha.
Well, in a fanfiction context, it could be possible if we consider a crossover universe where Naruto somehow ends up in the Star Wars galaxy. Maybe he's brainwashed by the dark side's influence which is similar to some dark forces in his own world. This could lead him to betray the Jedi ideals that he might have adopted during his time there.
In the realm of fanfiction, this situation might be crafted to explore deeper emotional and relationship aspects. The writer could be using this as a way to show a complex relationship between Naruto and Itachi. It could be that in this fanfic's universe, there are new types of chakra or abilities that make this pregnancy possible. For example, a special chakra bond between them that defies the normal biological limitations of the Naruto world. It also might be a means to shock the readers and draw them into a story that challenges their preconceived notions about the characters.
Well, in this fanfiction, Naruto might use his shadow clone jutsu to overwhelm the White Walkers. He could create a horde of clones and swarm them. Also, his Rasengan could be a powerful weapon against the undead. Just imagine Naruto spinning his Rasengan and blasting through a group of White Walkers.
Well, in a fanfiction world, anything can happen. Maybe Naruto discovers some Asgardian magic or meets Thor in a cross - dimensional event. This could lead him to become a huge fan of Thor, being inspired by Thor's strength and noble character.
Well, in a fanfiction, it could be possible if Orochimaru has a change of heart. Maybe Naruto's unwavering belief in redemption reaches Orochimaru. Naruto is known for seeing the good in people, and he might be able to convince Orochimaru to turn away from his dark ways. This new - found friendship could lead to Orochimaru using his vast knowledge for the good of the village, like helping with medical research or sharing his knowledge of forbidden jutsus in a more ethical way.