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.
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.
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 be entertained. The Flash, for example, would probably love the zany and often over - the - top stories in the fanfiction. He has a sense of humor and the Lego Batman world's wackiness would appeal to him.
He might isolate himself from the League at first. Batman is used to working alone, so he could retreat to his Batcave and plan his next move. He could also start to prepare counter - measures in case the situation escalates and the Justice League becomes a threat to him.
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.
Some members might be shocked and try to persuade him to stay. They know how valuable he is to the team, both in terms of his strategic mind and combat skills. Superman, for instance, might have a heart - to - heart talk with him, appealing to their long - standing friendship.
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 Justice League would likely be in shock. Superman, for example, would be deeply troubled as Batman was one of his closest allies. He would probably demand an investigation to find out the exact circumstances of Batman's death.
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.
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.