Another possibility is that Naruto found the mask himself during one of his adventures. It could be an ancient and powerful artifact. Since he's smart in this fanfic, he figures out how to use it to his advantage and decides to wear it to enhance his abilities in the ninja world.
Maybe it was Jiraiya. Jiraiya was a very important figure in Naruto's life. He could have given Naruto the mask as part of a training exercise. He might have thought that wearing a mask would force Naruto to rely more on his intelligence rather than his brute strength in certain situations.
Perhaps Naruto wears the mask as a symbol of a new, more strategic side of himself. He could be using it to intimidate his opponents in battle. Since he's smart in this fanfic, he might have realized that a mysterious appearance can give him an edge. He could be using the mask to play mind games with his enemies, making them wonder who he really is and what his true capabilities are.
One possible plot could be that Naruto wears a mask to hide his identity while on a secret mission in another village. He might be gathering intelligence about a new threat that could endanger the Hidden Leaf. While wearing the mask, he has to interact with the locals without giving away his true self, leading to some comical and tense situations.
One possible reason could be for disguise. Maybe he is on a secret mission and doesn't want to be recognized easily. In the Naruto world, there are many dangerous foes, and wearing a face mask can help him blend in or hide his identity from those who might be targeting him.
It could be a powerful and mysterious shinobi. Maybe someone from an ancient hidden village who has been observing Naruto for a long time and decided to give him the mask as a test or a way to unlock his true potential.
In the 'naruto has a mask fanfiction', it might be that Naruto finds the mask himself. He could stumble upon it during one of his adventures, perhaps in an ancient ruin or a hidden cave. The mask could be enchanted or have some special property that draws Naruto to it, and he decides to keep it and figure out its secrets on his own.
His enemies, too. They might realize that Naruto is not as straightforward as they thought. If he shows a more cunning side by dropping the mask, they would have to adjust their battle strategies. For example, Orochimaru might find Naruto a more formidable opponent than he initially believed.
If it's a more spiritual fanfiction, the mask could have a connection to the spirit world. Naruto wearing the mask could open a portal to that world or allow him to communicate with the spirits of past ninjas. He could then seek advice from the great ninjas of the past through the power of the mask.
Another possibility is that Naruto wears the mask as a tribute to Kakashi after a significant event. It could be that Kakashi sacrifices himself to save Naruto and the village. So, Naruto dons the mask to carry on Kakashi's legacy and to always remember the lessons he learned from him.
Well, at first, Naruto might seem like he's just having fun with the 'mask of idiocy'. But as the story progresses, he could start to use it more strategically. This would force him to think on his feet and adapt to different situations quickly. Through this, his confidence might grow, not just in his combat abilities but also in his ability to outwit his opponents. His relationships with his friends could also evolve. They might start to see a different side of him, and Naruto would have to learn how to handle their reactions. Overall, his character would become more complex and multifaceted in this fanfic.
The mask in the 'naruto has a mask fanfiction' might be a symbol of mystery. It could hide Naruto's true identity or feelings. Maybe he uses it to conceal a new power he has acquired and doesn't want his enemies to know about right away.