The Uchiha might initially be filled with anger. Their trust in Naruto, if it was there before, would be completely shattered. They could start to plot revenge against Naruto, believing that he has wronged them. This could lead to a lot of tense moments in the fanfiction as the Uchiha gather their strength and resources.
Imagine a ninja from another land who met Sasuke during a battle. She was a strong and independent fighter. After the battle, she was intrigued by Sasuke's skills and his complex personality. She started to seek him out, and they had many encounters. At first, Sasuke was dismissive, but her persistence and the unique bond they formed over time led to love. Their relationship was not easy, with Sasuke's past always looming, but their love prevailed in the end.
A villain like Shigaraki would likely be interested in the power levels in the MCU fanfiction. He's always looking for ways to increase his own power, and seeing the various powerful artifacts and abilities in the MCU might give him some ideas. He could think about how he could use similar things in his own plans to take over the MHA world.
Some Uchiha might be suspicious of her at first. After all, she's an outsider. But others may be curious about her skills, especially if they know she's a strong ninja from her own village. They could either welcome her with open arms if they see potential benefits from her visit, or keep her at a distance if they fear she might bring trouble.
Another theme is self - discovery. As Sasuke travels and faces various challenges, he gradually discovers more about himself, his powers, and his place in the ninja world. This is shown through his internal monologues and his reactions to different situations in the novels.
In Sasuke Uchiha lemon fanfics, he may be depicted with a more passionate side when it comes to love and relationships. His usual cold exterior might be softened to show his vulnerability in the context of these often - romantic and physical interactions. However, this is a deviation from his traditional character in the Naruto series where his main goals are related to power and vengeance. These fanfics often explore his character in a more romantic and sometimes sexually - charged way that is not part of the original story.
You should check out 'Naruto & Sasuke: Partners in a New World'. This fanfic takes the two characters and places them in a different, more modern - day like setting while still maintaining their core personalities. It's a fresh take on their relationship. And 'Sasuke's Return to Konoha' is a fanfic that focuses on Sasuke coming back to the village and how he and Naruto work together to improve the village and their standing in it. It has some great dialogue between the two.
Some MHA characters might be flattered. For example, Midoriya would probably be really excited and take it as a sign of how much he's inspired people. He might even look for positive lessons in the fanfiction to improve himself.
If the MHA characters were to react to a Mastermind fanfiction, some would be more accepting than others. Characters like Ochaco might find it really exciting. She's a fan of the heroes herself, so seeing different takes in fanfiction would be like getting a new perspective on the MHA world. However, characters like Shoto, who are more reserved, might be a bit hesitant. He might need some time to process what he's reading. But overall, it would be a very interesting scenario as it would show how the characters view different interpretations of their world.
Some characters would be shocked. For example, if the fanfiction had a really dark and unexpected Mastermind plot, like a hero turning out to be the mastermind of all the villains' plans, characters like Tsuyu would be very taken aback. She'd probably question the motives behind such a plot. Then there are characters like Denki. He might be more into it if it had some cool action scenes in the fanfiction, regardless of how out - of - the - blue the Mastermind storyline was. And Nejire would probably be super curious about the emotional depth of the characters in the fanfiction.