Sasuke would be really interesting. He already has a dark and brooding nature. Adding Ice Devil Slayer powers would enhance his cool and aloof demeanor. He could use the ice powers in combination with his Sharingan and fire - based jutsu in really unique ways. For example, he could freeze the water created by a water - style jutsu and then shatter it with his ice powers.
One idea could be a crossover where an Ice Devil Slayer from another dimension arrives in the Naruto world. They could team up with Naruto to fight against a new ice - based enemy that is freezing the land. This would bring a new element of magic to the Naruto universe.
One possible scenario in this fanfiction could be Naruto obtaining the ice devil fruit. This would completely change his combat style. He could use ice attacks in combination with his existing ninja techniques. For example, he might freeze an opponent's feet with ice and then follow up with a Rasengan. It would also add a new element to his character development as he'd have to learn to control this new power.
A possible fanfiction could involve Naruto learning Fire Devil Slayer Magic. Maybe he meets a character from the world of Devil Slayer who teaches him this magic. It could give him new powers and abilities, like the ability to control and manipulate fire in a different way compared to his normal jutsu.
One common theme is the combination of powers. Naruto's ninja powers are merged with devil slayer abilities in many fanfictions. For example, he might use his Rasengan with a devil slayer's fire - based attack.
One popular trope is the struggle between the Ice Devil Slayer's powers and their own humanity. Since they deal with ice - based magic, often there's a battle against the coldness within themselves. Another is the mentorship or rivalry with other Fairy Tail members. For example, they might learn from an older wizard or compete with a fellow guildmate in terms of power and skill development.
One possible plotline could be Naruto getting transported to a world where Satan exists and Devil Slayers operate. He might have to learn their ways to survive and end up using his ninja skills in new and unexpected ways. Another could be that a Devil Slayer ends up in the Naruto world and has to deal with the different chakra system while also facing off against Naruto - like enemies. And perhaps Satan has some connection to an ancient evil in the Naruto universe that they all have to fight together.
Well, if Naruto had Devil Slayer Magic, it could be really cool. He could use his chakra to enhance the magic. For example, his Rasengan could be combined with Devil Slayer Magic to create a more powerful and destructive attack. Maybe he could use the heat - based Devil Slayer Magic to make his attacks even hotter than normal fire - based jutsus.
Obviously Naruto is one of the main characters. And of course, the Ice God Slayer would be a main character as well. There might also be characters like Sasuke who could get involved, either as an ally or an antagonist depending on the plot.
He could use it for offense, like shooting out intense streams of fire at his enemies. It would be a more direct and powerful form of fire - based attack compared to some of his regular jutsu.