Kagura could be the most interesting. She already has a strong - willed and somewhat wild personality. When she meets Naruto, she would be intrigued by his powers. She might challenge him to a fight to see who's stronger. And because she has experience in both the alien world (her own origin) and the world of Gintama, she could act as a sort of bridge between Naruto and the Gintama characters. Her unique abilities combined with her no - nonsense attitude would make her a key figure in any interactions and plot developments in the crossover fanfiction.
I think Gintoki would be the most interesting. His laid - back and cynical nature would contrast so much with the more idealistic Naruto. He would constantly be making sarcastic remarks about Naruto's ninja -isms and the whole concept of being a hero. But at the same time, he would also be secretly impressed by Naruto's unwavering determination. And seeing Gintoki try to use Naruto's ninja tools or techniques in his own wacky way would be really entertaining.
Definitely Gaara. His ability to control sand is unique. In the Borderlands 2 setting, he could use his sand to protect his teammates from the various attacks, like from the psychos or the Loader Bots. His transformation into Shukaku could also be a very powerful and visually striking element in the crossover.
Naruto would be really interesting. His never - give - up attitude would make him stand out in the spooky FNAF world. He'd probably be the one to charge headfirst into danger, whether it's facing the creepy animatronics or trying to solve the mysteries of the place. He could also try to befriend the animatronics if he thought they were being controlled against their will, just like he did with some of his enemies in the Naruto world.
It could be Ben himself. Imagine him using his alien forms in the Naruto universe. His Heatblast form could be really useful against ice - based jutsu, and Four Arms could take on some of the physically strong ninja. He would bring a whole new element of power and chaos to the Naruto world, and his reactions to the different cultures and powers in Naruto's world would be interesting to explore.
Sasuke could be really engaging in this scenario. His cold and calculating nature would be a contrast to the chaos of the zombies. He might see the zombie outbreak as an opportunity to gain more power or find a way to use the situation to his advantage against his enemies in the Naruto world. And his Sharingan could potentially have some new abilities when dealing with the undead.
Sasuke could be a very interesting character in this crossover. He has his own dark and brooding nature. He might be more interested in the stronger and rarer Pokemon. His sharingan could give him an edge in understanding Pokemon's abilities and behaviors. He could also train Pokemon in a more intense and strict way compared to other trainers.
I think Naruto himself would be the most interesting. Just picture him with Hollow powers added to his already vast ninja skills. He's so full of energy and determination, and adding the element of Hollow abilities would take his character to a whole new level. He could use his newfound powers to protect his friends and the village in ways he never thought possible.
Definitely Naruto himself. He has such a strong personality and unique powers. In the Dishonored world, his ability to never give up and his positive attitude would be a fresh contrast to the often dark and brooding characters there. His ninjutsu skills would also make him a force to be reckoned with.
Kakashi could be an interesting addition too. His calm and collected demeanor, along with his vast knowledge and skills, would be very useful in the new and strange world of Kuroinu. He could serve as a mentor figure not only to the Naruto characters but also potentially to some of the Kuroinu characters who might be in need of guidance.
One of the most interesting interactions would be between Bayonetta and Hinata. Hinata's shy nature would be a stark contrast to Bayonetta's boldness. Bayonetta could inspire Hinata to be more confident in herself. Also, the interaction between Rock Lee and Bayonetta would be fun. Rock Lee would be eager to prove himself to her in combat, and Bayonetta would be entertained by his enthusiasm and unique fighting style.
War from Darksiders could also be a great crossover character. His brute strength and his weapon skills would be a contrast to the ninja in the Naruto world. He could be sent to the Naruto world on a mission and end up getting involved in the conflicts between the ninja villages. His war - like nature might make him either a feared or respected figure among the ninjas.