How about Gollum from Lord of the Rings? It seems really odd at first, but think about it. Gollum's sneaky nature and knowledge of dark places could be useful in Arkham Asylum. Batman could try to control Gollum's greed and use his skills to navigate the more dangerous parts of the asylum. And Gollum might be fascinated by Batman's shiny gadgets. It would be a very strange and interesting dynamic.
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.
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.
One idea could be that the Winchester brothers from Supernatural are investigating a series of strange murders in Gotham City. They cross paths with Batman who initially is suspicious of them. Eventually, they realize that a demon is behind the killings and they team up. Batman provides his detective skills and combat abilities while the Winchesters use their knowledge of the supernatural to defeat the demon.
One great Batman crossover fanfiction is 'Batman and the Avengers'. It combines the dark and brooding world of Batman with the high - powered superhero team of the Avengers. The story has some epic battles and interesting character interactions as Batman tries to hold his own among the likes of Iron Man and Captain America.
Another one worth checking out is 'The Caped Crusader in RWBY'. It delves deep into how Batman's code of ethics might change or stay the same in the RWBY universe. It also has some great fight scenes where Batman uses his martial arts skills against Grimm, all while trying to understand the complex politics of Remnant.
One great Batman crossover fanfiction is 'Batman and the Avengers: A Dark Alliance'. It combines the gritty world of Batman with the super - powered heroes of the Avengers in an exciting way. The story has some great action scenes and interesting character interactions, like Batman's tactical mind clashing with Iron Man's high - tech approach.
One of the best elements is seeing Batman interact with characters from different universes. For example, when he teams up with Superman, we get to see how their different moral compasses and powers play off each other. Another element is the new villains or threats that are created by the crossovers. It adds a fresh perspective to Batman's world.
A Batman and Witch Blade fanfic could be really interesting. It might involve a scenario where Batman discovers the Witch Blade in Gotham. Maybe he initially mistakes it for some new, dangerous weapon in the wrong hands. He could then try to track down its owner, which would lead him to the Witch Blade's wielder. And from there, they could either become allies against a common threat in Gotham or have some misunderstandings that need to be resolved.
Another possibility is a scenario where Voldemort decides to expand his reach into the non - magical world and Batman becomes aware of this threat. He would then enter Hogwarts undercover to learn about magic and form an alliance with the Order of the Phoenix. The contrast between Batman's brooding, non - magical detective nature and the magical world would make for an interesting story.