Maybe in the fanfic, Batman's rogues gallery somehow teams up with some of the Avengers' villains. This forces Batman and the Avengers to work together. Batman could introduce his unique gadgets and combat style to the Avengers, while they could show him their superpowers up close. For example, Iron Man could be intrigued by Batman's utility belt and try to create his own version of some of the gadgets.
One possible plot could be that Batman's Gotham is threatened by a powerful villain who has some connection to the Avengers' universe. Maybe Loki decides to cause chaos in Gotham as part of a larger plan against Earth. Batman, being the detective he is, starts to investigate and soon realizes that this is no ordinary criminal. He then somehow gets in touch with the Avengers, perhaps through SHIELD's intelligence network. Together, they combine their skills and resources to take on Loki and his minions. Batman's stealth and strategic mind would complement the Avengers' superpowers.
The plot could start with Batman getting an invitation from SHIELD. They've noticed some strange activities in Gotham that seem related to a threat that could affect the whole world. Batman joins the Avengers. He quickly realizes that their methods are very different from his. But he uses his stealth and detective skills to gather information that the Avengers couldn't. For example, he discovers a hidden base of the villains by following a small clue.
Batman and Iron Man would definitely have interesting interactions. They are both brilliant minds with vast resources at their disposal. Iron Man is more of a showman with his high - tech suits, while Batman is the brooding detective who prefers to work in the shadows. They would likely argue about the best way to approach a problem, but also learn from each other's methods.
In a 'batman and avengers crossover fanfiction', it could start with Batman being mysteriously transported to the Avengers' universe. He'd be a bit of a loner compared to the team - based Avengers. However, his intelligence would shine as he helps them deal with threats they've never faced before. For instance, against a new type of enemy that can't be defeated by brute force alone. Batman's utility belt and his ability to plan ahead would be crucial in such a crossover. He might even teach the Avengers a thing or two about being more strategic in their battles.
It could be really exciting. Batman's detective skills and gadgets would add a new dimension to the Avengers. He might outwit some of the Avengers' enemies with his superior intellect. For example, when facing Loki, Batman could use his knowledge of psychology to manipulate Loki's actions. His utility belt with all its cool gadgets like the grappling hook and batarangs would be a great addition to the team's arsenal.
He might fit in as a sort of mentor figure. He has years of experience fighting crime in Gotham. He could teach the younger Avengers like Spider - Man (if he's in the mix) some valuable lessons about perseverance and the importance of a strong moral code. Also, his physical combat skills would be useful in hand - to - hand battles against powerful foes.
A good plot could involve a villain from the Homestuck universe creating chaos in the Avengers' world. The Homestuck characters come to help, but there are misunderstandings at first between them and the Avengers. However, as they start to understand each other's powers and motives, they form a strong alliance to defeat the villain.
In a dark Gotham alley, Batman is on patrol when a strange web shoots across his path. Out of the shadows emerges Spider - Man. 'Hey, Bats! Heard this city could use some help.' Batman, initially cautious, realizes they could work together. They team up to take on a new villain who has a blend of high - tech gadgets and super - strength. Spider - Man's quips lighten the mood as Batman strategizes. Together, they swing and glide through Gotham, finally defeating the bad guy.
Batman would be the most interesting. He doesn't have superpowers like the Avengers, but he's still a formidable hero. His presence in their world would be like a wild card. He'd be constantly analyzing the Avengers and their enemies, and his dark, brooding nature would contrast with the more flashy and super - powered Avengers.