The members of the Justice League would likely have a range of reactions. Superman might be appalled if he is shown as a tyrant like in the Injustice story. Batman would probably analyze every detail, looking for lessons that could apply to their own world. Aquaman might not care much as he is often focused on his own underwater kingdom, but if the fanfiction somehow involves Atlantis in a negative way, he might get defensive. Green Lanterns could be interested in how the power of the rings is portrayed differently in the Injustice fanfiction compared to their own understanding.
Some might be amused, while others could be offended. It depends on how they are depicted in the fanfiction.
Each Justice League member's reaction would be unique. Flash might be initially excited to see how fast he is supposed to be in the fanfiction, but then be disappointed if his character is made to do unethical things for the sake of speed. Wonder Woman may be conflicted; she could see the strength of her character in the fanfiction but also be dismayed at any actions that go against her principles. Martian Manhunter, with his telepathic abilities, might be able to sense the darker undertones in the fanfiction more deeply and be concerned about the implications it has for their own universe.
Batman would probably be more critical. He'd analyze how the fanfiction portrays his detective skills and his relationship with the other members of the Justice League. He might not like it if the stories make him seem too soft or too brutal, as he has a very specific self - image.
Some might be shocked. For instance, Batman is often portrayed in very different ways in fanfiction compared to his 'canon' self. Superman might raise an eyebrow at a fanfic where Batman is overly emotional. Others like the Flash might be really into it, finding the different takes on Batman's character and his adventures exciting.
Some might like it, some might not. It depends on their personalities.
When it comes to the Justice League's reaction to The Dark Knight fanfiction, it's a diverse range. Batman, who is all about control and secrecy, may not like the liberties taken in the fanfiction. He could even feel that it undermines his real - life efforts. Superman, being the more optimistic of the group, could view it as a celebration of their superhero world. He might enjoy seeing how fans expand on the Dark Knight's story. Wonder Woman, coming from an ancient and different culture, would be fascinated by the modern human's creativity in the fanfiction. The Flash would be entertained by the fast - paced and often over - the - top nature of the fan - made stories. Aquaman, despite his initial confusion, could come to respect the unique view of heroism presented. Green Lantern would be thinking about how the fanfiction could inspire new ways to use his ring's power and enhance his heroics.
Superman might be a bit amused. He'd see the Naruto characters' struggles and compare them to the challenges he faces in Metropolis. Batman would probably study it like he does any case, trying to figure out the motives of the characters in the fanfiction. Wonder Woman would likely be drawn to the strong female characters in Naruto fanfiction, if there are any.
Superman may see the similarities in the heroism of the One Piece characters to his own. However, he'd also notice the differences in how they achieve their goals. He might think about how he could incorporate some of their fearless attitudes into his own battles back home. Batman would be very observant. He'd study the motives of the villains in the One Piece fanfiction and how the heroes counter them, and might even get some new ideas for dealing with Gotham's rogues.
Wonder Woman would probably respect Batman's decision. However, she would also be concerned about the void his departure would leave in the team. She might start taking on more of a leadership role to fill the gap, while also hoping that Batman would return one day.
The Justice League as a whole would have a diverse range of reactions. Some members like the Flash would be all for it, seeing it as a fun exploration of Batman. Others like Wonder Woman might use it as a way to understand how the public perceives Batman's role in the League. And then there are those like Aquaman who might just shrug it off unless it directly affects his interests. The fanfiction could also potentially create some internal discussions within the League about how they are all portrayed in the public's imagination.
Some of them might laugh. They would see the creative and sometimes out - there ideas that fans come up with in the fanfiction. For example, if there's a fanfic where Oliver Queen teams up with a really strange character from the Arrowverse, it could be quite humorous to them.
The Flash might initially be in denial. He's used to Batman always having a plan and his death would be a huge shock. He would then turn his speed into a tool for investigation, trying to find out exactly what happened. Green Lantern could feel a sense of loss but also be spurred into action, using his ring to try and prevent future tragedies like Batman's death. He might create constructs in Batman's memory to inspire the team.