Another storyline might involve Batman leaving because of a personal crisis. For example, he discovers something dark about his past that makes him question his place in the Justice League. He might think that he's a liability to the team and decide to leave to protect them.
The storyline could focus on Batman forming his own team. He might gather some of his old allies or even some new characters. This new team could operate in Gotham and deal with threats that the Justice League might overlook.
Another possibility in the fanfic is that Batman discovers some dark secrets within the Justice League. Maybe there's something corrupt or dangerous about the way they operate that he can't tolerate. So, to protect his own integrity and the safety of Gotham, he chooses to leave the team.
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.
Batman's sacrifice would likely have a huge impact on the Justice League. It could make them more determined to uphold justice in his memory. They might also become more cautious as they've lost a great strategist.
Batman is a master strategist. He would study the weaknesses of each Justice League member beforehand. For example, he knows that Superman has a weakness to Kryptonite. He would also use his advanced technology and gadgets to even the odds. His bat - suit is equipped with various tools that can be used against different opponents.
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.
Well, it often makes the team more protective. They start to realize just how vulnerable Batman is despite his skills. For example, Superman might become more vigilant about looking out for Batman during battles.
In some fanfictions, Batman might be injured while investigating a dangerous conspiracy. He gets too close to the truth and the people behind it try to eliminate him. They set up traps, like a high - tech booby - trapped building. Batman is caught in an explosion or a collapsing structure, which results in his injury. Then the Justice League has to come to his rescue and deal with the conspiracy.