Perhaps in this fanfiction, Naruto starts to have dreams about his parents where they seem distant and unrecognizable. This makes him search for answers, leading him on a journey where he uncovers secrets about his family that were long buried. As he digs deeper, he realizes that there were forces at work that made it seem like his parents forgot him, when in reality, it was a much more complex situation.
Well, there could be characters like Iruka - sensei. Since Naruto has been forgotten by his parents, Iruka might play an even more important role in Naruto's life, becoming like a surrogate father figure. Another character could be Sasuke. Sasuke, who also has his own family issues, might either be a source of understanding for Naruto or a contrast to his situation.
In this kind of situation, Naruto might first feel extremely sad and lonely. He could start by trying to prove himself to others. Maybe he'd focus on his ninja training more than ever, using it as a way to distract himself from the pain of being forgotten by his parents.
Common themes in this type of fanfiction are abandonment and its consequences. Naruto's world is turned upside down by his parents' forgetfulness. Another theme is the search for acceptance. He wants to be accepted by the village and by others, but it's harder when he has this gaping hole in his family history. Also, the theme of inner strength is present. He has to dig deep within himself to find the strength to carry on. It's about how he can build his own self - worth when those who should have given it to him from the start (his parents) are absent.
One possible reason could be a curse. Maybe some enemy put a curse on Naruto's parents that made them forget about him. It could be a way to get back at them by targeting their most precious thing, which is their son.
One good one is 'Forgotten but Not Gone'. It really delves into how Fem Harry feels being overlooked by her parents. The story shows her struggle to find her place in the wizarding world on her own terms.
Emotionally, Naruto would have to deal with a whole new set of family relationships. He grew up without his parents, and now having them back would be a huge adjustment. He might struggle to fit into a 'normal' family dynamic, and there could be some friction as they all get to know each other again.
In some fanfictions, Naruto might find a super - powerful jutsu or artifact. For example, he could discover a long - lost forbidden jutsu that has the power to bring the dead back to life. Or perhaps he stumbles upon a magical item during one of his adventures that is said to be able to revive the deceased.
On a personal level, Naruto would finally get the family he always wanted. But it might also bring some confusion and adjustment issues. His parents would be from a different time, and they'd need to adapt to the new world Naruto lives in. For example, they might be shocked by the new technology and the changes in ninja warfare.
Iruka could play a role. He was Naruto's first teacher who believed in him. He might have some small piece of information that starts Naruto on his journey to find his parents. Then there's Tsunade. As the Hokage, she has access to a lot of secret files. She could either be an obstacle, not wanting Naruto to dig too deep, or she could be a helper, providing him with crucial information. And of course, the Nine - Tailed Fox. It was sealed inside Naruto by his father, so it might have some memories or knowledge related to Naruto's parents that it could share with Naruto.