Who could be the one that stabs Naruto in 'naruto gets stabbed fanfiction'?

Maybe it's an enemy from another village who sees Naruto as a threat to their plans. For example, if there's a group in another village that wants to start a war, they might think that getting rid of Naruto would give them an advantage. Another possibility is that it's a character who has been brainwashed or controlled by an evil force. This could add an interesting layer to the story as Naruto's friends would have to not only deal with his injury but also find a way to break the control on the stabber.

It could be Sakura. In the original series, their relationship was complex, and in fanfiction, it would be a common choice for her to be the one to dump Naruto, perhaps due to her still having feelings for Sasuke.

Maybe Kakashi could still be his mentor. Even though One for All is a new and different power, Kakashi is very experienced. He could help Naruto understand how to incorporate this new power into his overall combat strategy. Kakashi would be able to analyze the power and give Naruto advice on how to train with it while still relying on his ninja skills.

It could be an enemy ninja from another village who wants to take out Konoha's strongest shinobi. Maybe someone from the Sound Village still holding a grudge against Naruto.

Sakura would be a likely candidate. As a skilled medical ninja, she has the knowledge and ability to diagnose the poison and attempt to create an antidote.

It could be Orochimaru. He's always interested in powerful artifacts, and the mask Naruto gets would be no exception. Orochimaru would likely try to steal the mask from Naruto to add to his collection of powerful items and use its power for his own dark experiments.

Sakura could potentially be Naruto's girlfriend in some fanfictions. Although in the original series she had feelings for Sasuke for a long time, in fan - created stories, the writers might explore a different path where she realizes Naruto's true worth and they end up together.

He could marry Mikasa from Attack on Titan. Just think about it. Naruto's positive and determined personality would contrast with Mikasa's more stoic and protective nature. They could meet through some sort of interdimensional accident. Naruto would be fascinated by the Titans and the world outside his own, and Mikasa might be intrigued by Naruto's ninja abilities.

He could marry Hinata. Even though he's banished, Hinata might follow him because of her deep love for him. Their relationship could develop further outside the village, and they could get married and start a family.

Well, in 'naruto gets stabbed fanfiction', it could be that Naruto is exploring a new and dangerous area where he encounters a powerful and hostile ninja. In the heat of the fight, this ninja manages to land a stabbing blow. It might also be that Naruto is weakened due to some prior injury or chakra depletion, making him more vulnerable to being stabbed by a regular enemy. And, there could be a situation where Naruto is under the influence of some sort of genjutsu that impairs his ability to defend himself and thus gets stabbed.