Another great pairing could be Peter Parker (Spiderman) and Albert Wesker. It would be a very dynamic duo as Wesker has his own mysterious and powerful abilities. Peter, with his scientific knowledge and superhero skills, could either be in conflict with Wesker or end up having to work with him in a strange alliance to stop an even greater threat in a complex plot.
Sakura and Jill Valentine would be a great match. Sakura is a strong - willed and skilled kunoichi, and Jill is a tough and resourceful Resident Evil character. They could share their combat experiences, with Sakura teaching Jill some of her medical ninjutsu and Jill teaching Sakura how to better handle firearms and survive in a more post - apocalyptic environment.
Chris Redfield and Master Chief. Chris is a tough and experienced fighter in the Resident Evil series. Master Chief, from Halo, has his own set of skills and military training. If they were in a crossover, they could lead a joint military operation against a combined force of Covenant and bio - organic threats from Resident Evil. It would be interesting to see how their different combat styles and leadership skills would work together. Also, Ada Wong and Catwoman could be a fun pairing. Their stealth and cunning nature could lead to some interesting heists or espionage - related storylines within the crossover.
Spiderman and Green Lantern. Green Lantern's power ring can create all kinds of constructs, and Spiderman could use his webs to enhance or modify those constructs. They could work together to build a huge structure to stop a giant alien invasion that is threatening both the Marvel and DC universes.
One possible plot could be that a bio - hazard outbreak occurs in New York City. Spiderman has to not only fight the usual criminals but also deal with the infected. Meanwhile, some Resident Evil characters like Leon S. Kennedy are sent to investigate the outbreak. They cross paths with Spiderman, and at first there is mistrust, but they soon realize they need to work together to stop the spread of the virus and take down the mastermind behind it, perhaps a new villain who has combined Oscorp technology with Umbrella Corporation's bio - weapons.
Naruto and Ruby would be an interesting pairing. Naruto's positive and energetic nature would contrast well with Ruby's somewhat more reserved but determined self. They could bond over their shared goal of protecting their friends and worlds. Another great pairing could be Sasuke and Weiss. Sasuke's cool and brooding demeanor against Weiss' ice - cold exterior would make for some intense interactions. They could also learn from each other's combat styles. And then there's Kakashi and Blake. Kakashi's wisdom and experience as a ninja could help Blake with her own inner demons and her fight against the White Fang, while Blake could introduce Kakashi to the concept of the Faunus in the RWBY world.
Spiderman and Erza would make for a strong pairing. Erza is a very powerful and disciplined mage. Spiderman could be in awe of her combat skills and leadership. They could fight side - side against powerful enemies, with Spiderman using his webs and agility and Erza with her various armors and weapons.
Ragna from Blazblue and Ruby from RWBY could be an interesting pairing. Ragna is a brooding anti - hero with a powerful combat ability, while Ruby is an optimistic and energetic young huntress. Their different personalities could lead to some great character interactions, like Ragna being a bit cynical at first but slowly being influenced by Ruby's positive attitude. Another interesting pairing could be a Persona user, say Yu from Persona 4, and Jin from Blazblue. Jin is a cold and reserved swordsman, and Yu could use his empathetic nature and Persona powers to try to break through Jin's icy exterior. And for a third pairing, Blake from RWBY and a Persona user like Akechi from Persona 5. Blake has her own secrets and a complex past, and Akechi's dual nature could create an interesting dynamic as they both have things they are hiding.
Blake and Brian could be an amazing duo. Blake, with her love for books and her complex past, and Brian, the intelligent dog who is also a bit of a philosopher. They could have deep conversations about ethics and morality, all while being in a world that is a mash - up of RWBY and Family Guy.
Yang and the special forces' hand - to - hand combat expert. Yang is already a powerful fighter in close - quarters combat. The combat expert could teach her new moves and ways to better control her strength, while Yang could show the expert how to use her Semblance to her advantage in combat.
Definitely Naruto and Natsu. They are both the main protagonists in their respective series and have a lot of energy and a strong sense of justice. Their interactions would be really fun to read, like when they compete to see who can defeat the most enemies or who has the stronger fire - related power.