Another possibility is an evil organization that wants to break Naruto's spirit. They figure that by making his family forget him, they can weaken Naruto both emotionally and in terms of his ninja capabilities. They might use dark magic or some sort of advanced genjutsu to plant false memories in Naruto's family members' minds, making them believe that Naruto is no longer the Naruto they knew and loved.
Maybe the main antagonist is a member of Naruto's own family who is power - hungry. This family member sees Naruto's growth to the Jounin level as a threat to their own position within the family. So, they manipulate the rest of the family into forgetting Naruto and excluding him from the family unit. They would stop at nothing to keep Naruto away and maintain their own power and influence.
One possible plot could be that Naruto, having reached the Jounin level, is suddenly shunned by his family. Maybe due to some false accusations or misunderstandings within the family. His family might cut off all communication with him, leaving Naruto to fend for himself while still carrying out his Jounin duties. He would have to struggle not only with the regular challenges of being a Jounin but also with the emotional pain of being forgotten by those he loves.
Maybe it's an evil organization that wants to isolate Naruto. By making his family forget him, they hope to break Naruto's spirit and prevent him from becoming a powerful force in the ninja world. So they target his family's memories as a way to get to him.
Maybe he would have mastered some new wind - style jutsus. For example, he could create more complex and powerful wind blades that can cut through even stronger defenses. Since he is at the Jounin level, his chakra control would be much more refined, enabling him to perform these advanced techniques.
It could be Orochimaru. He's always been interested in experimenting and causing chaos. Maybe he wants to use Naruto's parents' forgetfulness as a way to study the Uzumaki clan's mental state or something related to their chakra. He might see Naruto's vulnerability in this situation as an opportunity to get closer to his goals.
It could be a jealous relative who wants Naruto out of the picture so they can have more attention or power within the family.
It could be a family member who has a personal vendetta against Naruto and is the main instigator of his being shunned. Maybe an older cousin who is jealous of Naruto's potential.
It could be a rogue ninja who has a vendetta against Naruto and wants to target his family. Maybe this ninja was once defeated by Naruto and now wants to take revenge by harming his loved ones, especially his and Sakura's child.
Kakashi could be an obvious choice. He's already a well - known and highly skilled jounin. His Sharingan and his laid - back yet effective teaching style could make for an interesting story as an elite jounin.
The Organization in the Claymore world could be the main antagonist. They already have a lot of secrets and do some morally ambiguous things. If Naruto shows up and starts changing the status quo, like teaching Claymore warriors to be more independent, the Organization might see him as a threat and try to eliminate him.
It could be a rogue ninja who was once a student of Orochimaru and has now developed his own dangerous jutsu. He wants to take over the ninja world and believes the old ways are holding everyone back.