Naruto for sure. And then there could be a female Pilot who is a brilliant strategist. She initially doubts Naruto's strange powers but then comes to respect and rely on them. Also, an older, more experienced Pilot who has seen a lot in the Titanfall world could be a main character. He acts as a mentor to Naruto and the younger Pilot, and together they form an unlikely but powerful team.
In a naruto x titanfall fanfiction, Naruto would be the central character from the Naruto side. On the Titanfall side, a maverick Pilot who doesn't always follow the rules could be a main character. This Pilot has a special bond with his Titan, which is also a key character. The Titan has unique modifications that make it stand out. Their interactions with Naruto would be full of drama, action, and learning as they try to survive in a world that is a blend of two very different universes.
Obviously Naruto would be one of the main characters. He could bring his unique ninja abilities and his indomitable spirit to the Titanfall universe. Another main character could be a Pilot, maybe a young and inexperienced one who Naruto befriends and helps grow. And a Titan itself could also be considered a main character in a way, as it has its own personality and capabilities that interact with Naruto and the Pilot.
Ruby could be a main character. Her speed and scythe - wielding skills would be really interesting to see in the Titanfall universe. She could quickly adapt to piloting a Titan and use her scythe in new and creative ways during battles.
One possible plot could be that Naruto somehow gets transported to the Titanfall universe. He might use his ninja skills to outmaneuver the Titans at first, but then he starts to learn about the technology there and teams up with some of the Pilots. Maybe he teaches them some of his chakra - based techniques in exchange for learning how to pilot a Titan.
Obviously Naruto and Wolverine could be main characters. Wolverine's tough - guy attitude and his healing factor would contrast well with Naruto's upbeat and determined personality. Jean Grey could also be a main character. Her powerful telepathic and telekinetic abilities would be interesting to see in the Naruto world, especially when interacting with ninjas who rely on physical and chakra - based skills.
In a Naruto x Shake It Up fanfiction, Naruto and Flynn could also be main characters. Flynn is always full of surprises and his comical nature along with Naruto's heroic and sometimes clueless nature about the modern world (since Shake It Up is a more modern - day setting) would create a lot of humorous and adventurous situations. Also, Gaara from Naruto could be brought in. His brooding personality would contrast well with the energetic Shake It Up characters.
Obviously, Naruto would be the central character. But in the genderbend version, characters like Sasuke, Sakura, Hinata, etc. would be genderbent. Sasuke as a female could bring a whole new dynamic to the story. She might be more of a femme fatale type, still having her strong will and desire for revenge but with a different charm. Sakura as a male could be the big - hearted but sometimes clumsy character, always trying to prove himself to Naruto. Hinata as a male could be more shy and reserved, yet still having a deep - seated love for Naruto.
Sasuke could also be a main character in such a fanfiction. His thirst for power and his Sharingan could make him a key figure. He might be interested in the advanced technology in Ghost in the Shell as a way to further his own goals. And perhaps he would cross paths with some of the Section 9 agents.
Well, Naruto is a must - have as the main character. In terms of the Jedi, Rey could be in the harem. Since she has a lot of potential and is learning about the Force, she would be interested in Naruto's abilities. Also, Padmé Amidala could be included. Even though she's not a Jedi, she has a strong presence and could be attracted to Naruto's heroic nature. And of course, there could be other original Jedi characters created specifically for this fanfiction.
Another option could be Naruto and Luna. Luna is all about music and Naruto is about ninjutsu. But they could bond over their passion for their respective crafts. They might find that they have a lot in common in terms of determination and drive. And together, they could face any challenges that come their way in this fanfiction world.
I think Naruto, Rogue, and Cyclops could be main characters. Rogue's power - absorbing ability could be an interesting element when combined with Naruto's chakra - based powers. And Cyclops could be the leader - like figure guiding their team - up against common enemies. The three of them could have a really complex relationship, with Rogue sometimes being a bit of a wildcard due to her power and Naruto and Cyclops trying to keep the team focused.
Obviously, Summer and Naruto would be the main focuses. Summer, with her skills and backstory from RWBY, would bring her own set of abilities and relationships to the story. Naruto, on the other hand, is full of energy and has his powerful ninja techniques. Their interactions would be central to the fanfiction.