In the fanfiction, a plot twist could be that Naruto's smithing skills attract the attention of an enemy. This enemy wants to use Naruto's skills for their own evil purposes. But Naruto, being Naruto, refuses and uses his newly acquired smithing knowledge to create weapons and defenses specifically designed to counter this new threat.
One possible plot twist could be that Naruto discovers he has a natural affinity for a special type of metal that is only found in a hidden realm. This metal has unique properties that can enhance his ninja tools in unexpected ways. Another could be that the smithing skills he learns are actually part of an ancient prophecy. It was foretold that a ninja with Naruto's spirit would master smithing to create a weapon that could save the ninja world from a great threat that is yet to come.
One possible plot twist could be that Naruto discovers a hidden aspect of the Hiraishin no Jutsu. For example, it might have a connection to an ancient Uzumaki clan ability that no one knew about. This could lead to Naruto being able to use it in ways that Minato, his father, never did.
It could enhance his ability to customize his ninja tools. For example, he might be able to make kunai that are sharper and more durable, giving him an edge in combat. Also, if he can smith special tools that can better channel his chakra, like a new type of shuriken, his ranged attacks could become more powerful.
One possible plot twist could be that his heritage is linked to an enemy he thought was unrelated. So he has to reevaluate his views on the whole conflict.
A plot twist could be that Naruto's Fuinjutsu skills are actually part of a prophecy in Kumo. The village initially hid this from him, but as he progresses in learning, he discovers the truth and has to deal with the implications.
In a 'naruto learns kenjutsu fanfiction', one possible plot could be that Naruto decides to learn kenjutsu to diversify his combat skills. He might seek out a master swordsman in a hidden village. The master could initially be reluctant to teach him, seeing Naruto as a rowdy ninja. But as Naruto shows his determination and unique ninja way, the master changes his mind. Naruto then has to go through rigorous training, learning different sword stances and techniques. Along the way, he might face opponents who are skilled in kenjutsu and use those battles to improve his skills further.
Well, in a 'Naruto learns nen' fanfiction, perhaps Naruto is sent to a different dimension where nen is the dominant power source. There, he has to learn nen to survive and find his way back home. He starts from the basics, learning about the different nen types like Enhancer, Transmuter etc. As he progresses, he combines his knowledge of ninjutsu with nen, creating unique and powerful attacks.
Well, one possibility is that Naruto learns hypnosis from a mysterious ninja. This new skill helps him in battles by confusing his opponents. He could use it to make enemies see illusions of multiple Narutos, giving him an edge in combat.
The fanfiction might be about Naruto accidentally stumbling upon a ancient scroll that contains the secrets of bending. He decides to learn it out of curiosity. He begins with fire bending, which is a challenge as it's very different from his chakra - based fire techniques. But with his ninja training and unwavering will, he manages to figure out how to control the flames in the new way of bending.
A possible plot twist in this 'Ash Learns He's a Pokemon Fanfiction' scenario is that Ash finds out that his relationships with his Pokemon are being manipulated by the author of the fanfiction. His Pokemon might start acting out of character, or new Pokemon might join his team in unexpected ways. This would make Ash feel like he has no control over his journey. He'd have to fight against the author's will, in a sense, to regain the normalcy of his relationship with his Pokemon and continue his journey as he wants to.
Well, one possible plot could be that Naruto travels to a foreign land where Muay Thai is popular. He meets a tough Muay Thai master who initially doubts Naruto's abilities but is soon impressed by his determination. Naruto then starts training rigorously, facing challenges like learning the unique stances and powerful kicks of Muay Thai. As he progresses, he combines his ninja skills with Muay Thai techniques, creating a new and formidable fighting style.