Maybe there's a storyline where they team up against a common enemy. A powerful criminal who uses both high - tech gadgets like Batman's villains and has a dark, serial - killer - like mind like Dexter's prey. They have to combine their skills, Batman's detective work and combat skills with Dexter's forensic knowledge and ability to blend in.
A possible storyline is that Dexter gets framed in Gotham and Batman has to figure out if he's really guilty. Batman starts investigating Dexter's past and his double life in Miami. This forces Dexter to either reveal his true self to Batman or try to escape Gotham while being hunted by both the Gotham police and Batman.
One interesting storyline could be Catwoman stealing a valuable artifact that has a connection to Batman's past. This forces Batman to track her down, but as he does, he discovers that Catwoman has her own reasons for taking it that are more complex than simple theft. Another could be a situation where Catwoman and Batman are forced to team up against a greater threat in Gotham, like a new super - villain who is out to destroy the city. And a third one might be a story where Catwoman tries to frame Batman for a crime he didn't commit, leading to a tense cat - and - mouse chase between them.
Well, in fanfiction, it could go either way depending on how the author writes it. If the story focuses on Dexter's home turf and his ability to manipulate the situation, he could win. But Batman is a symbol of justice and has a lot of experience dealing with all kinds of threats. He has contingency plans for almost everything. So, more often than not, Batman might emerge victorious in a battle between the two.
A really cool storyline might be a situation where they are both framed for a crime they didn't commit. They have to work together to clear their names while also dealing with their own personal issues. Batman might be suspicious of Green Arrow at first, and vice versa. This would create a lot of tension and drama. Also, a fanfiction where they are transported to an alternate universe and have to find their way back could be exciting. They would face new challenges and enemies that test their abilities in different ways.
A storyline could involve Nightwing being framed for a crime in Gotham. Batman, believing the evidence at first, tries to bring him in. Nightwing, of course, resists as he is innocent, and this leads to their fight. As the story progresses, they both realize there's a bigger conspiracy at play.
One interesting storyline could be a reimagining of Batman's first encounter with the Joker in the 1939 fanfiction context. Maybe the Joker starts as a small - time criminal and Batman has to figure out his true motives early on.
One interesting storyline could be Batman having to deal with a new villain who has the power to manipulate time while also trying to maintain his normal life as Bruce Wayne. This would add a whole new layer of complexity to his dual identity.
One possible storyline could be that Batman discovers a conspiracy within the Justice League that endangers Gotham. So he and Robin decide to take on the League to stop it. Another could be that the Justice League is being mind - controlled, and Batman and Robin are the only ones who realize it and try to free their friends by fighting them. Or perhaps there's a misunderstanding where the Justice League believes Batman and Robin have turned bad, and they have to fight to prove their innocence.
Another idea could be a team - up against a greater threat. Despite their differences, they realize that a powerful enemy is beyond their individual capabilities. They have to combine their skills, Batman's detective skills and high - tech gadgets with Rorschach's street - smart and unorthodox fighting style. This could lead to some great action scenes and also character development as they learn to work together.
One interesting plot could be that Batman and Catwoman are forced to team up against a greater threat in the fanfiction. Maybe a new supervillain emerges who is more powerful than any they've faced before, and they have to put aside their differences to save Gotham.
One interesting scenario could be a battle in a dark, abandoned cityscape. Itachi's Sharingan abilities would give him an edge in terms of perception and illusions. Batman, on the other hand, would rely on his gadgets and combat skills. He might use smoke bombs to disrupt Itachi's line of sight and then try to get in close with his martial arts. Another scenario could be a mental battle. Itachi is used to psychological warfare, but Batman is also a master of getting into his opponents' heads. Itachi might try to use his genjutsu to break Batman's will, but Batman's strong mental discipline could resist it.