Maybe Naruto has some sort of disagreement or falling - out with his family. This could lead him to seek a new start in Kiri. For example, if there are differences in values or expectations within his family that he can't reconcile with, he might choose to leave.
Another reason could be related to his ninja goals. He may believe that Kiri has unique ninja techniques or training methods that can help him become a stronger ninja. He could be thinking that by joining Kiri, he can gain more power and knowledge to achieve his long - term goals, like protecting his loved ones in a better way in the future.
He might face a lot of challenges at first. The people in Kiri may not trust him easily as he is an outsider. But Naruto, with his determination, would start to prove himself by showing his ninja skills and his good heart.
One reason could be that he feels betrayed in Konoha. Maybe some secrets were uncovered about the village's past actions towards him or his family that made him lose faith. So, he decides to start anew in Kiri where he hopes to find a different kind of acceptance.
One possible reason could be that he discovers some long - hidden family secrets that make him feel betrayed. For example, if he finds out that his family was involved in something unethical in the past. Another reason might be that he feels constantly overshadowed by his family's legacy and can't form his own identity within the family, so he decides to leave to find himself.
Maybe he feels ostracized in Konoha. If for some reason the villagers still don't fully accept him despite his heroics, he could be lured by the idea of a fresh start in Iwa.
One possible reason could be to protect her. Naruto might believe that by leaving, he can draw danger away from his sister. For example, if there are powerful enemies targeting him, he doesn't want his sister to get caught in the crossfire.
One possible reason could be to seek greater power and training opportunities elsewhere. Maybe he feels restricted within his clan in terms of the type of jutsu he can learn or the level of training he can receive. So, he decides to leave to explore different ninja arts and grow stronger on his own terms.
One possible reason could be a long - held misunderstanding. Maybe Naruto discovers some family secrets that he misinterprets as betrayal or neglect. For example, if he finds out that his family had made some sort of pact that he disagrees with, it could lead to his rejection.
One possible reason could be that he has some unresolved issues from his past, like the absence of his parents during his childhood which made him feel a sense of detachment. Maybe he is so focused on achieving his ninja goals that he unconsciously starts to ignore his family. Another reason might be some sort of miscommunication within the family. For example, if there are secrets that the family has been keeping from him, he might feel betrayed and thus choose to ignore them.
In some fanfics, Naruto might leave his family because of a dangerous threat approaching them. He could believe that by leaving, he would draw the danger away and keep his family safe.
One possible reason could be to avoid the political intrigue in the village. With his new inheritance, he might feel that he can't fully develop or use it while being constantly under the watchful eyes and political games in the village.