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.
His family would probably be overjoyed. After all, they might have thought they'd lost him forever. There would be hugs and tears, and a flood of questions about his life and what he's been through.
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.
If it's a Disney fanfiction based on a princess story, the female characters in MHA like Momo Yaoyorozu might relate to the princesses' grace and leadership. Meanwhile, the male characters could either be in awe or a bit dismissive, depending on their personalities. For example, Todoroki might be quietly respectful, while Mineta might make some inappropriate remarks (if we're being honest about his character).
MHA characters might also be a bit jealous of some of the superpowers or unique abilities in other anime fanfiction. In their world, quirks are relatively well - defined, but in some other anime, there are really out - of - this - world powers. They could be in awe of the creativity and at the same time, try to figure out how they could incorporate some of those ideas into their own fighting styles. Like, if they read a fanfiction about a character who can manipulate time, they might start thinking about how they could use their quirks in a time - related way.
A possible main character could be a journalist who is intrigued by Master Chief's retirement. The journalist wants to write a story about him and follows him around. Additionally, there could be a group of children on the retirement planet. Master Chief could form a bond with them, teaching them valuable life lessons, and they could be important characters in the fanfiction as they represent the future and hope.
[Grandmaster Huijue is the chief master of the twelve caves.] In the 'Bad People' series, Master Huijue had always been by Li Xingyun's side, and he possessed powers comparable to a greater celestial. In the plot, he solved the secret of Buddha's Cloak and provided help to Li Xingyun and the others. Master Huijue's identity was revealed in the plot. He was the chief master who had sent the 11th master to rescue Li Xingyun and the others. In addition, the Buddha beads in Master Huijue's hands were exactly the same as the Buddha beads of the 12 masters. This was also one of the reasons why the audience suspected that he was the chief master. Thus, it could be confirmed that Master Huijue was the chief master of the twelve caves.
In a crossover with the DC universe, Superman could be an interesting character to pair with Master Chief. They are both strong and have a sense of justice, but their powers and methods are very different. Another good one could be Batman. The contrast between the high - tech Master Chief and the more detective - style Batman would make for an exciting story. In the Marvel universe, Captain America would be a great pairing. Their leadership skills and commitment to their causes could create some great interactions.