Lex Luthor is often a main antagonist. He might be the one who sets up the situation where Superman needs to be saved, like creating a powerful weapon or a devious plan to weaken Superman.
One possible storyline could be that Batman has to use his detective skills to find out a hidden threat to Superman before saving him. Maybe there's a kryptonite - based weapon that only Batman can detect and disable.
A theme that frequently appears is redemption. Sometimes Batman might be in a situation because of a mistake he made, and Superman saving him is a form of redemption. Also, the theme of heroism is prominent. Superman's act of saving Batman reaffirms their status as heroes and shows their selfless nature towards each other.
When Batman saves Superman, it could make him more confident in his own abilities outside of his normal Gotham - based operations. He realizes that his skills as a detective, strategist, and fighter are not just useful in his own city but can be applied on a much larger scale. This could lead to him being more involved in Justice League - related matters and having a more positive outlook on working with super - powered individuals in general. He might also become more empathetic as he gets to understand Superman's vulnerabilities better.
Well, one popular 'superman saves batman fanfiction' is 'The Rescue in Gotham'. In this story, Superman arrives just in time to save Batman from a powerful new villain who has him cornered in an abandoned warehouse. The action scenes are really well - written, and it shows a great dynamic between the two heroes.
Well, in a fanfic about Batman and Superman's friendship and fatherhood, they could be depicted as mentors to their sidekicks in a more fatherly way. Batman with Robin and Superman with Superboy perhaps. Their friendship might be tested as they balance their superhero duties and their newfound father - like roles.
One aspect of a Batman - Superman friendship fanfic could be how they overcome their differences. Batman is a dark, brooding vigilante while Superman is the all - American hero. Their friendship might start from a mutual respect for each other's abilities. For example, in a story, they could team up to fight a common enemy that neither could defeat alone. This would force them to rely on each other and learn about the other's strengths and weaknesses.
One common theme could be the exploration of their complex relationship in a more romantic or sexual context. Another might be the power dynamics between the two very powerful characters.
One common theme is the corruption of power. Maybe Superman's power has gone to his head, and Batman sees the need to stop him at all costs. Another could be a mind - control scenario where Superman is being controlled by an outside force and Batman has no other option.
One interesting Batman Superman fanfic could be about them teaming up to face a new, extremely powerful villain that neither could defeat alone. For example, a villain with the power to manipulate time. In the story, Batman's strategic mind and Superman's superpowers combine in unique ways to outwit the foe.