In some fanfictions, Naruto might defeat his sister in a battle of ideologies. For example, if his sister has been influenced by a dark force and Naruto uses his positive ninja way to convince her to change her views, it can be seen as a form of 'defeat'.
There are various ways in fanfiction for Naruto to defeat his sister. Maybe she is competing with Naruto for a powerful ninja artifact. Naruto, with his determination and growth over the years, could outwit her. He might use his strategic thinking, his ability to make allies, and his combat skills that he has honed through countless battles to emerge victorious.
In certain fanfictions, Naruto could approach the paperwork in a more diplomatic way. He might convince others in the village, like his friends or some of the ninja clans, to help him with the paperwork. By using his charisma and leadership skills, which he has developed over time, he gets everyone to pitch in. And with their combined efforts, they manage to defeat the mountain of paperwork. After all, Naruto is not just a powerful fighter but also a great leader who can inspire people to work together.
In many fanfictions, Naruto might defeat Kaguya by unlocking a new form or power. For example, he could master a more advanced version of Sage Mode or combine his Nine - Tails chakra in a completely new way. This new power could give him the edge needed to outmatch Kaguya's abilities.
In many fanfictions, Naruto might defeat Sasuke through mastering a new jutsu. For example, he could develop a super - powerful Rasengan variant that overpowers Sasuke's Sharingan - based attacks. Maybe he combines his Sage Mode with the Nine - Tails' chakra in a unique way that Sasuke can't counter.
In some fanfictions, Naruto might show his love for his sister by protecting her at all costs. For example, he would stand in front of any danger that comes her way, just like how he protects his friends in the original story.
In such a fanfiction, Naruto could die in various ways. Maybe his sister is somehow possessed and attacks him fatally. Or there could be a situation where she accidentally causes his death during a fight due to a lack of control over her power.
She could be very sad. After all, Naruto is likely an important person in her life. She might feel abandoned and start to question why Naruto left her.
Another way is if his sister has some special powers that she can't fully control yet in the fanfiction world. And during a training session or an accidental encounter, her powers lash out and end up hurting Naruto.
He might try to prove himself. Naruto has always been a determined character. He could focus on his ninja training more intently, aiming to show everyone his worth despite being neglected. Maybe he'd also start to distance himself a bit from his family situation and form closer bonds with his friends like Sasuke and Sakura, who might understand and support him through this tough time.
Naruto might initially be in shock. He has always counted on Kushina's love, and this sudden abandonment would be a huge blow. He could become withdrawn and quiet, not understanding why his mother would do such a thing.
Well, Naruto could also seek support from his friends like Sasuke or Sakura. They have been through a lot together, and they might be able to offer him some comfort and advice on how to handle this difficult situation. Since Naruto values his friendships highly, their words could have a big impact on him.