Kakashi would be deeply affected. He has a soft spot for Naruto, and seeing him like this would stir up a lot of emotions. He might have a flashback to when he lost his own comrades, and that would make him even more determined to protect Naruto. His face would be solemn, and his voice would be gentle as he tries to soothe Naruto. He would also start thinking about how to make Naruto stronger so that he doesn't have to go through this again, all while feeling a great deal of pain inside seeing Naruto in such a vulnerable state.
He'd probably be a mix of angry and sad. Angry at whoever or whatever caused Naruto to be in this state, and sad because he cares about Naruto so much. He might clench his fists tightly, trying to control his emotions while he focuses on helping Naruto. He'd also feel a sense of guilt, wondering if he could have prevented this from happening.
Kakashi would likely be very concerned. He would immediately assess Naruto's injuries. If they were serious, he would use his medical skills to start treating him right away. His first reaction would be to make sure Naruto was stable and out of immediate danger.
Kakashi might immediately offer a comforting presence. He could put his hand on Naruto's shoulder and just be there silently, letting Naruto know he's not alone.
One possibility is that Kakashi would immediately use his medical ninjutsu to treat Naruto's wounds if he has the skills. Then he'd try to calm Naruto down by talking softly to him, asking what happened. He might vow to protect Naruto better in the future and start investigating the cause of Naruto's harm.
Kakashi might be initially surprised. But then, he would probably use it as a teaching moment for Naruto. He could say something like 'Naruto, stealing is not the way of a ninja.' And then give him a punishment like extra training.
Well, Kakashi is a complex character. When he discovers Naruto is abused in the fanfiction, he may first feel a deep sense of guilt for not noticing earlier. He'd then use his skills and influence in the village. He could start by reporting it to the proper authorities in Konoha, like the Hokage. And at the same time, he'd be there for Naruto, providing emotional support, talking to him, and helping him through the trauma. Kakashi has his own past traumas, so he'd understand what Naruto is going through on some level.
One possible plot could be that Naruto was on a mission alone and got ambushed by a group of rogue ninjas. Kakashi, while out on his own patrol, stumbles upon the injured Naruto. He quickly takes Naruto to a safe place and uses his medical ninjutsu to stabilize him. Then, he might start to investigate who attacked Naruto and why, leading to a revenge - based sub - plot or uncovering a larger conspiracy against Konoha.
He probably gets very worried. Kakashi is Naruto's teacher and mentor, so he'd likely be immediately concerned and rush to Naruto's side to assess the situation.
Kakashi's reaction would be complex. He is a man who has lost many people in his life. But Naruto was special. He would hold Naruto tightly, his hands trembling slightly. He might try to use some of his own chakra to keep Naruto alive a little longer, but deep down he knows it's futile. His face would show a mixture of pain, regret, and love. He would remember all the times he trained Naruto, all the lessons he taught him, and how Naruto had surpassed all expectations.
He may be surprised. Fanfictions can have some really out - there ideas that he might not have considered before. For instance, a fanfiction might have Naruto suddenly having a new, super - powerful jutsu that was never seen in the original series.
Kakashi might be initially shocked. After all, Naruto has always been his student and the sudden refusal to use the term'sensei' would be unexpected.