In my opinion, Faith from Buffy and Alec from Dark Angel would be great to focus on. Faith has her own troubled past and her unique slayer abilities. Alec, on the other hand, is a transgenic with a bit of a roguish charm. The two of them could have a really interesting dynamic. Maybe they start off as rivals, not trusting each other, but as they face a common enemy, they start to understand and respect each other. And of course, Buffy and Max are also must - haves. They are the main characters of their respective shows and their leadership skills and different outlooks on life would make for a great story.
Abby and Logan could be a great pair. Abby is the brilliant NCIS forensic scientist, and Logan is a journalist in the Dark Angel world. They could work together to uncover the truth behind a conspiracy that involves both the military - related cases of NCIS and the transgenic secrets in Dark Angel. Abby could use her scientific knowledge to analyze evidence, and Logan could use his journalistic skills to dig up information and expose the truth to the public.
One idea could be that the vampires in Buffy's world somehow cross over to the Dark Angel universe and the transgenic characters have to deal with them. They might initially mistake vampires for some new kind of transgenic experiment gone wrong. Another idea is that Buffy herself travels to the Dark Angel world and teams up with Max to fight against a common enemy that is threatening both of their worlds, like a powerful demon that has found a way to use transgenic technology for evil purposes.
Definitely Ben and Ash. Ben with his Omnitrix and ability to transform into different aliens brings a whole new dimension of power and adventure. Ash, on the other hand, has his experience and deep connection with Pokemon. Their interactions would be fascinating. For instance, Ben might be amazed at how Ash can communicate with his Pokemon without any high - tech device, and Ash could be in awe of Ben's alien forms and their powers.
Batman and Black Widow would be really interesting. Batman is all about mystery and detective work in the shadows, while Black Widow is a master spy. They could learn a lot from each other's skills in stealth and intelligence gathering. Also, Thor and Batman could be a great focus. Thor with his god - like powers and Batman with his human ingenuity. Imagine Batman trying to figure out the science behind Thor's hammer while Thor is amused by Batman's determination in the face of the supernatural.
Definitely Naruto and Geralt. Naruto with his bright - eyed optimism and powerful ninja skills would contrast greatly with Geralt's brooding and more practical monster - hunting skills. Their interactions would be full of learning and cultural clashes. For example, Naruto might be shocked at how Geralt deals with certain 'monsters' that in Naruto's world could potentially be redeemed. And Geralt would be intrigued by Naruto's chakra and jutsu.
Definitely Naruto and Link. Naruto's energetic and determined personality would contrast well with Link's more stoic nature. They could learn a lot from each other. Also, Zelda would be interesting. Her wisdom and magical abilities would add a different dimension. And Sasuke could also be a great character to include. His dark past and thirst for power could lead to some interesting interactions in the Zelda world, especially when faced with the power of the Triforce.
Definitely Naruto and the main Guyver character. Naruto because of his determination and growth throughout the Naruto series. He would be really interesting to see how he adapts to the Guyver's powers. And the Guyver, because its powers are so unique and different from the ninja abilities in Naruto. Their interactions could be full of misunderstandings at first as they come from different worlds, but then they could learn from each other.
Hulk would be an interesting character to focus on. Imagine the dynamic between him and Wolverine. They both have superhuman strength and a bit of a wild side. Their fight could be epic, but then they could also form an unlikely alliance. Also, Black Widow could add an element of mystery and stealth to the story. Her skills in espionage and combat could be useful in a plot where the team is trying to uncover a secret conspiracy related to Wolverine's past.
Vilgax from Ben 10 could be an interesting character to include. If he somehow gets his hands on a Green Lantern ring or the technology related to it, he could become an even more formidable foe. This would force Ben and the Green Lanterns to team up against a common enemy who has combined the power of both universes in a dangerous way.
The Flash (Barry Allen) could also be a great character to include. Since he has crossovers with both Arrow and Supergirl in the actual shows. His light - hearted nature and super - speed abilities could add a different dynamic to the story. He could act as a mediator between Oliver and Kara when they have differences. Also, villains like Lex Luthor could be really interesting to explore in this crossover. His brilliant mind and devious plans could pose a significant threat to both heroes and force them to work together in new ways.