His origin and motivation. Batman's motivation is mainly personal revenge and protecting Gotham, which is more self - centered compared to the more global - saving motives of some Justice League members. In fanfiction, this difference in origin and motivation might make him seem less like a 'true' Justice League superhero.
One reason could be his methods. Batman uses more unorthodox and often darker tactics compared to other Justice League members. This might make some people think he's not a 'typical' superhero in the context of Justice League fanfiction.
His personality. Batman is often a loner and very brooding. In fanfiction, this can be at odds with the more team - friendly and positive - energy superheroes in the Justice League. So, this difference in personality could lead to the statement.
This could be a title. It might be exploring a new take on Batman in fanfiction. In many Justice League fanfictions, Batman is usually seen as a core superhero. But this title seems to be suggesting a different perspective, perhaps that Batman has his own unique identity that doesn't align with the common perception of a superhero in the Justice League fanfiction world. It could lead to a story that delves into Batman's more complex and non - traditional characteristics.
Maybe to save the Justice League from a powerful enemy. He might sacrifice himself if it means the others can escape or defeat the foe.
Maybe he feels betrayed. In fanfiction, there could be a situation where his fellow Justice League members keep secrets from him. For instance, Superman could be hiding something about his true powers or his origin that could potentially be dangerous. Batman, being the detective he is, values truth and transparency, and such secrets might make him feel that he can no longer trust his teammates and thus quit.
Perhaps Batman feels betrayed by his fellow members. A secret could be revealed about one of them that makes Batman lose faith in the integrity of the group. He's all about trust and if that's broken, he'd be likely to walk away.
One possible reason could be a misunderstanding. Maybe the Justice League misinterprets Batman's actions as being against them when in fact he's trying to protect them in his own way. For example, Batman might be keeping a secret that he thinks is for the greater good, but the League sees it as a betrayal of trust.
One reason could be a moral disagreement. Batman has a very strict moral code. If the Justice League were to engage in actions that he considered too extreme or unethical, he might quit. For example, if they started using excessive force on villains without proper trial. Another reason could be burnout. Constantly fighting crime and dealing with the politics within the Justice League could take a toll on him. He might feel that he needs to step away to regain his sanity and focus on protecting Gotham in his own way.
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.
In this fanfiction, Batman might not join the Justice League because he has a deep - seated belief in his own self - reliance. He has spent years building his skills, his network in Gotham, and his arsenal. Joining the League would mean having to rely on others, which goes against his independent nature. Also, he may fear that his identity could be more easily compromised within the League. His need to keep his dual identity a secret is crucial, and being around so many powerful and inquisitive individuals in the Justice League could pose a threat to that secrecy.
Maybe Batman discovers a dark secret within the Justice League that the other members don't want him to expose. So, they decide to kick him out to keep their secrets buried. It could be something related to the origin of a certain power or a hidden alliance that has some unethical implications.
One reason could be Batman's extreme independence. He's used to operating on his own terms in Gotham. He might see the Justice League's group dynamic as restrictive and interfering with his unique brand of justice. For example, he has his own way of interrogating criminals which might not be acceptable in the more 'by - the - book' Justice League environment.