Sasuke's reaction could be complex. At first, he would be enraged. After all, the Rinnegan is a symbol of his power and his journey to gain strength. However, he might also have some mixed feelings. He and Naruto have a deep bond, and he might wonder if Naruto had a good reason for taking it. But overall, his initial reaction would likely be one of fury and a desire to get his power back.
In the manga, Sasuke doesn't regain his Rinnegan. The story progresses without this particular change. The power he had before is maintained without reverting or regaining additional abilities related to the Rinnegan.
One plot implication could be a shift in the power balance in the Naruto universe. With Naruto having the Rinnegan, the Akatsuki or other villainous groups might see him as an even greater threat and target him more aggressively. Another aspect could be the relationship between Naruto and Sasuke. Sasuke giving away such a powerful ability shows a great deal of trust and sacrifice. It could lead to a deeper bond between them, and they might team up more often to face new challenges.
Well, in the Naruto fandom, everyone has different opinions. Some could be writing 'naruto rinnegan sasuke bashing fanfiction' because they are fans of other characters and feel that Sasuke overshadows them. For example, if someone is a huge Naruto fan, they might write such fanfiction to make Naruto seem more heroic in comparison to Sasuke. Also, some might just want to explore different storylines where Sasuke isn't the 'favored' character, especially when it comes to his rinnegan power which made him extremely powerful in the original series.
Their relationship would likely become more complex. With the Rinnegan involved, they might have to rely on each other more for understanding its powers. They could become more protective of each other, knowing the power and the danger it brings.
On the other hand, Sasuke could be worried. He may think that Naruto is in some kind of trouble or danger. Given their history and the care they have for each other in the SasuNaru dynamic, Sasuke's concern could lead him to be more protective. He might start investigating the situation on his own to figure out why Naruto is hiding his face and ensure his safety.
It could also be part of a strategic move. By hiding his bloodline, he can surprise his opponents in battle. They would underestimate him based on not knowing about his true powers, and then he could turn the tables on them when the time is right. This gives him an edge in combat situations.
Another reason could be related to his personal growth. He might be trying to master the power of the eye in private. Naruto has always been one to face challenges alone at first. By hiding his eye, he can focus on understanding and using its power without distractions or the pressure of others' expectations.
One possible reason could be that his eyes hold a special power that he doesn't want others to discover easily. For example, it might be a new type of Sharingan or a unique ability related to his Uzumaki heritage that he needs to keep secret to protect himself or those around him.