I think Kai would be really interesting. His hot - headed nature and his power over fire could make for some intense scenes in the Star Wars universe. He might be like a maverick Jedi or a Sith who doesn't quite follow the rules. He could get into battles with Stormtroopers using his fire powers in really creative ways.
I think Darth Vader and Dr. Doofenshmirtz would make an interesting crossover. Darth Vader's dark and menacing presence combined with Dr. Doofenshmirtz's comical evil - scientist shtick could lead to some really funny and unexpected interactions. Maybe Dr. Doofenshmirtz tries to steal Vader's lightsaber for one of his 'evil -inator' plans, and Vader is just completely confused by this strange little man.
Definitely Harry Potter and Luke Skywalker. They both are heroes on a journey to defeat great evils. They could learn from each other's experiences and powers. Harry could show Luke some of the more subtle forms of magic, and Luke could teach Harry about the Force.
Luke Skywalker and Amuro Ray would make an interesting crossover. Luke's Jedi skills and Amuro's Gundam piloting abilities could lead to some great action scenes. They could learn from each other, like Luke teaching Amuro about the Force and Amuro showing Luke the ins and outs of Gundam technology.
Snape and Kylo Ren could be an unexpected but interesting crossover. Snape's complex character, his past mistakes and his hidden loyalties could be compared to Kylo Ren's inner turmoil. Snape might see some of his own struggles in Kylo Ren and try to either redeem him or use him for his own purposes. And Hagrid and Chewbacca would be a fun crossover. They are both big, lovable characters with a heart of gold, and seeing them interact would bring some light - hearted moments to the story.
Dumbledore could be an extremely interesting crossover character. His wisdom and powerful magic would make him a force to be reckoned with in the Kantai Collection world. He could potentially teach the shipgirls about different forms of magic, and his ability to see the bigger picture would be useful in strategizing against the Abyssal threats.
Jaime Lannister would be an unexpected but interesting choice. He's a skilled swordsman with a complex personality. In the 'Hunger Games', he'd have to grapple with his own sense of honor and self - preservation. His relationship with other tributes could be full of drama, as he's used to the political and personal intrigues of the Seven Kingdoms. Plus, his golden hand could be a unique weapon or advantage in the arena.
Harley Quinn and Rey could be a popular crossover. Rey is a strong female character in Star Wars, and Harley Quinn has a very distinct personality. A fanfic could explore how Rey's determination and Harley Quinn's chaos - loving nature would interact, maybe they team up to take on a group of bad guys in a very unorthodox way.
Naruto himself would be very interesting. His never - give - up attitude and powerful jutsu would make him a great addition to the AOT world. He could inspire the people there to keep fighting against the Titans. His ability to make friends easily might also help in uniting different groups in the AOT world.
I think Naruto himself. His never - give - up attitude and his ability to make friends easily would make for great interactions in FF14. He could inspire the other players or characters in the game to be more brave and determined.
I think Jack Sparrow from 'Pirates of the Caribbean' would be really cool to cross over with Hercules. Jack's wily and unpredictable nature would contrast with Hercules' more straightforward heroism. They could be on a quest for a magical artifact that has the power to either save or destroy the world. It would be full of adventure, humor, and unexpected twists.