I think Alice could be a very powerful character in the crossover. She can see the future, which would give her group a huge advantage. They could avoid dangerous situations with walkers or other threats before they even happen. And her speed and fighting skills as a vampire would also make her a force to be reckoned with.
It would probably be Naruto. His ability to summon large amounts of chakra and perform powerful jutsus like the Rasengan and Sage Mode would make him extremely formidable against zombies. He could also use his chakra to sense the presence of the undead from a distance, giving him an edge in survival.
It's likely Naruto himself. His ability to create multiple clones, his superhuman strength and speed from his training as a ninja, and his rasengan attack would be extremely effective against the walkers. He could easily take out large groups of them in no time.
Naruto himself would be very interesting. His ability to see the good in people and his strong willpower would contrast greatly with the bleak and often hopeless world of The Walking Dead. He would bring a new perspective to the survivors there, and his ninja powers would make him a force to be reckoned with against the zombies.
It's likely Klaus Mikaelson. He's an Original vampire - werewolf hybrid in The Originals. He has super strength, speed, and his werewolf side gives him an edge in combat. In comparison, the vampires in Twilight, while strong, don't have the added advantage of being part werewolf. Also, Klaus has a lot of experience and is very cunning, which would make him a formidable force in a crossover situation.
Most likely Alucard. In the Hellsing universe, he is an extremely powerful vampire with a vast array of abilities. In comparison, the vampires in Twilight, while having their own strengths, seem rather weak when pitted against Alucard. He can manipulate shadows, has superhuman strength far beyond what we see in Twilight vampires, and his immortality is of a different level altogether.
I think Cortana and Michonne would be an interesting pairing. Cortana has all this knowledge and intelligence, while Michonne is a fierce fighter. Cortana could provide strategic advice to Michonne, and Michonne could teach Cortana about the realities of survival in a world full of the undead. They could form a really unique bond.
Definitely Rick Grimes and Captain America. Rick is a natural leader in a world full of zombies, and Captain America is a symbol of leadership and justice in the Avengers world. They could share their leadership experiences and strategies to fight against the combined threats.
Naruto and Rick would be a really interesting combination. Naruto's optimism and never - give - up attitude could inspire Rick, who has seen so much horror. And Rick's leadership skills and survival instincts could teach Naruto a thing or two about dealing with a post - apocalyptic world. They could work together to lead their respective groups and fight off the walkers and any other threats.
Michonne and Sam Winchester would be a great pairing too. Michonne is a skilled fighter with her katana, and Sam is very intelligent and well - read. They could work together to research any possible links between the walkers and the supernatural. Sam could also help Michonne come to terms with any new, otherworldly threats they encounter.
Dean Winchester and Daryl Dixon would make an amazing pairing. Dean's tough - guy attitude and his skills with weapons combined with Daryl's survival skills in a post - apocalyptic world would be really cool to see. They could go on zombie - hunting trips together while also sharing stories about their pasts.