At first, Naruto would probably be really confused. The fanfiction world is often a wild place with all kinds of interpretations. But then he might start to see the charm in it. He could find fanfictions that give his friends more backstory or depth that he didn't know before. He might also come across some really wacky ideas that make him laugh. However, he might also be a bit defensive if the fanfiction goes against his values or the way he sees his relationships in his own world.
He might be surprised. He's used to his own life and adventures, and seeing it twisted and turned in fanfiction could be unexpected.
Sakura would probably tease Naruto a little bit. She might say something like 'Naruto, you're such a dork for reading that fanfiction.' But then she would also be interested in what it's about and might ask Naruto to tell her some of the cool parts.
Sakura might tease Naruto about it a little. She'd probably think it's a bit strange that he's interested in something so different from their own world. But she'd also be curious to know what it's all about.
Naruto would be very curious. He'd want to understand what's going on. Once he figures out that there's a big battle between different factions, he'd try to find a peaceful solution. He might start by talking to the leaders, using his charm and persuasion skills. If that doesn't work, he'd use his ninja powers to protect the innocent. He's not one to just stand by when there's injustice.
He might be really surprised. Some fanfictions could have really out - of - the - box ideas that he'd never thought of. For example, if there's a fanfiction about him having a different kind of training with a new teacher, he'd be like 'Whoa, that's a new take on things.'
Naruto would probably first try to fight back. He's not the type to just go along with being kidnapped. He'd likely use his Shadow Clone Jutsu to create a distraction and try to escape.
He might be entertained. The abridged versions often have humor and can make light of serious situations in the original Naruto story.
Naruto would probably be initially shocked. He's a very loyal person, so he'd have a hard time believing it at first. Then he'd likely be very angry. He has a temper when it comes to things that are unjust, and this would be a huge betrayal. He might also feel really sad and disappointed in himself for not seeing the signs earlier.
Naruto would probably be extremely hurt. He has always looked up to the Sandaime as a grandfather figure. So, he might initially go into a state of shock and disbelief.
Initially, Naruto would be in shock. He'd try to talk to his friends like Sasuke or Sakura, but when they look at him with blank stares, it would break his heart. He would feel like an outsider in his own village. But then, his ninja spirit would kick in. He would start investigating. He might think it has something to do with a new enemy or some hidden plot. He'd be on a mission to not only get his friends and family to remember him but also to protect the village from whatever threat caused this forgetting in the first place.
Naruto would probably be very kind and protective. He knows what it's like to be alone as a child, so he'd do his best to make the child feel safe and loved.