Well, Naruto is a strong - willed character. In this fanfiction scenario, he might initially be heartbroken. But as time passes, he could use this abandonment as motivation. He may focus on becoming stronger, not just physically but also mentally. He might look for new friends or allies who can support him, and he could also try to keep an eye on his sister from afar to understand why he was abandoned for her.
He might feel a great deal of pain and confusion at first. Naruto could start to question his self - worth. Maybe he tries to find out the reasons behind the abandonment on his own, becoming more independent in the process.
In this fanfiction setting, Naruto's reaction to being abandoned for his sister could be complex. He may have an internal struggle. On one hand, he might have feelings of anger towards his family for abandoning him. On the other hand, he could still have a sense of love for his sister. Naruto could try to prove himself to those who abandoned him. He might start to train harder, learn new jutsu, and show that he is worthy of love and respect. He may also try to find a new family or community within the ninja world that accepts him for who he is, rather than being defined by his abandonment.