Lois Lane is often a popular character. In fanfiction, she might play a crucial role in mediating between Batman and Superman or getting involved in their adventures in a more hands - on way, using her investigative journalism skills.
The key characters are Batman, Superman, and Lex Luthor. Batman is the Dark Knight, a vigilante with no superpowers but great detective skills and combat abilities. Superman is the Man of Steel, an alien from Krypton with super strength, speed, and other amazing powers. Lex Luthor is a brilliant but devious billionaire who sees Superman as a threat to his own power and plans to destroy him by pitting him against Batman.
One main plot point is the ideological clash between Batman and Superman. Batman sees Superman as a potential threat to humanity due to his god - like powers. Superman, on the other hand, is just trying to do good but is often misunderstood. Another point is Lex Luthor's manipulation. He fuels Batman's distrust of Superman and sets them on a collision course. Also, the discovery of Kryptonite by Batman gives him a means to potentially defeat Superman in a fight.
One interesting plot could be Batman and Superman having to team up against a common enemy that is more powerful than either of them alone. This forces them to put aside their differences and combine their skills.
One possible reason could be mind control. Maybe some villain has taken over Superman's mind and made him do it. Another reason might be a fundamental difference in their ideologies that has escalated to the point of no return.
Alfred Pennyworth is quite popular too. He can offer his wisdom and support to Batman, and his interactions with Superman can be both humorous and heartwarming. He's like the glue that holds things together in the Batcave, and his presence can bring a sense of home to the story.
Often it starts with mutual respect. They recognize each other's abilities and dedication to justice. For instance, Superman respects Batman's ability to fight crime without powers, and Batman respects Superman's selfless use of his powers.
It's more modern in terms of art and storytelling. The New 52 version has a different aesthetic compared to older comics. It often has a faster - paced plot.
Lex Luthor is often an interesting character in such fanfictions. He might be the one pulling the strings behind the scenes, fueling Batman's distrust of Superman. Another could be Alfred. His wisdom and influence on Batman can add depth to the story. He might try to talk Batman out of fighting Superman or help him in a more covert way. And then there's Wonder Woman. She could be caught in the middle, trying to mediate between the two or having her own motives for getting involved in their conflict.
Catwoman can also be a popular character. She could be in a love - triangle situation with Batman, and her thieving ways might put her at odds with the female Superman who stands for truth and justice. There could be some really interesting interactions between the three of them, like Catwoman trying to steal a valuable item that the female Superman is protecting, while Batman is caught in the middle, not sure who to side with at first.