Some members might be shocked. Wonder Woman, for instance, who respects Batman's skills and tenacity, would likely be very disappointed. She might try to persuade him to stay, emphasizing the importance of his presence in the team. Superman, on the other hand, might initially be understanding, as he knows Batman has his own way of doing things. But he would also be concerned about the power vacuum that Batman's departure would create. Aquaman might be more indifferent, thinking that Batman was always an outsider to some extent, with his focus mainly on land - based issues.
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.
In such a fanfiction, they might team up to fight a powerful new villain. For example, a super - intelligent alien who plans to take over the Earth. The Justice League could initially be skeptical of Supergirl, but as they see her powers in action, they come to respect her.
Some of them might be amused. They could find the different takes on their characters and stories quite entertaining. For example, Superman might chuckle at a fanfic that has him in a comical situation.
I think Flash himself would be really interested. After all, it's about him. He'd be curious to see how the writer of the fanfiction portrays his character, his powers, and his relationships with the other members of the Justice League.
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 character dynamics could be complex. Supergirl, being new to the Justice League scene, would be the outsider. She'd be trying to fit in while also maintaining her own identity. Superman would be torn between his loyalty to the League and his family connection to Supergirl. And the other members like Cyborg and Martian Manhunter would be observing, trying to figure out where she stands in the grand scheme of things. This could lead to a lot of interesting interactions, from friendly banter to tense standoffs.
Well, it could be about the Justice League members sitting down and reacting to the Flash's adventures in the fanfiction. Maybe they laugh at his silly mistakes or are in awe of his heroic deeds in the made - up stories.