In a fanfic where Naruto gets stabbed in the back, who could be the likely culprit?

It could be an old enemy seeking revenge. Maybe a powerful Titan who escaped Tartarus and blames Percy for his previous defeat. This Titan could have been plotting in secret, waiting for the perfect moment to strike and finally end Percy's life.

Maybe it's a new villain who is trying to make a name for themselves. This villain could see shooting Captain America as a way to gain instant notoriety in the criminal underworld. They might have studied Captain America's weaknesses and found an opportune moment to strike.

Another possibility is a character who has been possessed by an evil spirit. They may not be in their right mind when they stab Merlin. This could add an element of mystery as Merlin has to figure out not only who stabbed him but also how to exorcise the spirit from the person's body.

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 a rogue ninja from a neighboring village. Maybe they were hired by a shadowy organization that wanted to disrupt the balance of power. This ninja might have been specifically targeting Naruto because of his status as a hero and a symbol of hope for the Hidden Leaf Village.

It could be an old enemy of Nicole's from her police work. Maybe someone she put in jail before who has a vendetta against her. This person might have been released recently and is out for revenge.

Perhaps it's a new character who has a grudge against the dojo in general. They target Jack because he is one of the most prominent students. This new character could be someone who was rejected from the dojo in the past and is now seeking revenge.

Perhaps an enemy from a rival group. They might see Sakura as a threat to their plans, so they poison her to get her out of the way. Another possibility is a character who has been secretly harboring a grudge against her for a long time, and finally decides to take action by poisoning her.

In 'naruto gets stabbed fanfiction', it might be a new enemy that has emerged, someone with a powerful and unknown jutsu. This enemy could see Naruto as a threat to their plans and decide to stab him to eliminate him. Or it could be a character who has been corrupted by dark power, like a former friend or ally who has fallen to the dark side and no longer recognizes Naruto as a friend.

It could be a powerful Hollows or Arrancar. Since they are often the antagonists in the Bleach universe, they might see Naruto as an intruder or a threat to their plans. Maybe a powerful Hollow with a thirst for powerful souls targets Naruto, thinking his unique chakra would be a great addition to its power.