One interesting concept could be having villains from different universes team up to take over a new, shared world. For example, the Joker from DC and Venom from Marvel joining forces. Another idea is a villain crossover where they are forced to work together against a greater evil, like Darth Vader and Magneto having to face an all - powerful cosmic entity. Or perhaps a crossover where the villains' personalities clash in humorous ways as they try to carry out their evil plans, like Dr. Doom and Maleficent trying to out - evil each other while also trying to cooperate.
A great concept for a villain crossover fanfic is a crossover within a single franchise but different timelines. For instance, in the Star Wars universe, having Emperor Palpatine from the prequel trilogy team up with Kylo Ren from the sequel trilogy. They could plot to destroy the new - found hope in the galaxy in a more devious way than they could alone. Another concept could be a villain crossover where the villains swap places. So, like Sauron from Middle - earth suddenly finding himself in Gotham City, and the Penguin finding himself in Middle - earth. How they adapt to their new environments while still trying to be evil could make for an exciting fanfic.
Well, a cool concept for a villain crossover fanfic could be a time - traveling villain crossover. Picture Lex Luthor from DC traveling back in time and teaming up with the Daleks from Doctor Who. They could use their combined intellect and resources to try and change history in their favor. Also, a villain crossover in a post - apocalyptic setting would be interesting. Imagine the Governor from The Walking Dead and the Witch - King from The Lord of the Rings ruling over a desolate wasteland together, each bringing their own brand of tyranny.
Another concept is the Joker's influence on the story's tone. In a crossover with a more light - hearted or comical universe, the Joker could still bring his dark and menacing presence, which would create a really interesting contrast. His actions and words could disrupt the normalcy of that universe and force the other characters to deal with a level of chaos they're not used to.
Another concept could be a time - travel - based crossover. Suppose Doraemon crosses over with Doctor Who. They could both explore different time periods and dimensions together. Doraemon's Time Machine and Doctor Who's TARDIS are both means of time travel, but they have different functions and appearances. Their combined adventures would be full of mystery and discovery.
One interesting concept is character interactions. For example, seeing how characters from different timelines or universes react when they meet. Another is the alteration of established storylines. It can create unique plot twists.
One interesting concept could be a 'Warhammer' crossover with 'Lord of the Rings'. Imagine the orcs from 'Warhammer' interacting with the orcs from Middle - earth. Another could be a crossover with 'Star Wars', like the Space Marines teaming up with the Jedi or Sith in some strange alternate universe scenario. And a 'Warhammer' and 'Harry Potter' crossover where the magic of the wizarding world meets the dark and gritty world of 'Warhammer' would also be really cool.
One interesting concept could be a Godzilla crossover with other giant monster franchises like King Kong. It could lead to epic battles and new storylines where they have to team up or fight over territory. Another concept might be a crossover with a superhero universe. Imagine Godzilla facing off against the Avengers or Justice League, which would require different strategies from both sides.
One interesting concept could be a xenomorph crossover with a superhero universe. Imagine a xenomorph invading a city where superheroes exist. The heroes would have to use their unique powers to fight this alien threat. For example, a telekinetic hero could try to hold the xenomorph in place while others figure out a way to kill it.
One interesting concept could be the interaction between Ultron and characters from different universes. For example, how Ultron would react to superheroes with completely different powers and moral compasses.
One interesting concept could be the combination of different Sonic universes. For example, merging the classic Sonic games' world with the more modern Sonic Boom universe. This can lead to unique character interactions, like Sonic from the classic era meeting Sticks from Sonic Boom.
One interesting concept could be the crossover with other popular anime. For example, crossing over with 'Your Lie in April' might bring a unique blend of the two stories' emotional tones. The characters from 'oregairu' could interact with the musically - inclined characters of 'Your Lie in April', creating new and unexpected relationships and storylines.
Another concept might be Ichigo crossing over with superheroes from Western comics. Picture Ichigo fighting alongside Superman or Batman. His unique reiatsu - based powers would be a great contrast to the superhuman abilities of the superheroes, and they could learn from each other's fighting styles.