The main villain could be an ice demon with the power to manipulate time. It freezes entire villages in different time loops, causing chaos. Naruto and the demon slayers must figure out how to break the time - frozen spells and defeat this powerful demon. The demon could also have the ability to create illusions, making it even harder for the heroes to fight it.
Maybe Naruto already has some hidden ice - related abilities in his Uzumaki heritage that he didn't know about. In the fanfiction, he meets a group of Ice Demon Slayers who recognize this potential in him. They train him to master his ice powers so he can help them defeat an ancient ice demon that has awakened. Along the way, Naruto also teaches the demon slayers some of his ninja skills, creating a great exchange of abilities.
In fanfiction about Naruto and Demon Slayer with magic, one interesting aspect is the potential for new power - ups. For instance, a character could combine the Sharingan from Naruto with a Demon Slayer's special vision ability and create a super - powered form of sight. Also, the magic could be used to explain some of the more mysterious elements in both series. Maybe the curse marks in Naruto are actually a form of suppressed magic, and in the fanfiction, a character figures out how to fully utilize this magic, taking on a new and powerful form inspired by Demon Slayer's demon - slaying forms.
Magic in this type of fanfiction can be used to bridge the gap between the two universes. It can make the transition of characters from one world to another more believable. For example, if Naruto characters enter the Demon Slayer world, magic could be the reason they can adapt to the new rules and powers there.
In this fanfiction, perhaps Sasuke could be a sort of anti - hero. He might initially be seen as a threat by the Demon Slayer corps because of his dark powers. But then, as the story progresses, he could use his Sharingan to detect demons more easily and work with the protagonists to defeat stronger demons.
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.
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.
Well, it would be quite a mix-up. Naruto's ninja skills and determination could add a new dynamic to the fight against demons. Maybe he'd form unexpected alliances or bring new strategies to the table.
One popular plotline could be the Ice Dragon Slayer character from a different world ending up in the Naruto universe. They might have to adapt to the ninja world while also using their ice dragon slaying abilities in unique ways, like fighting the Akatsuki. Another could be the Ice Dragon Slayer training Naruto or some of the other ninja in ice - based techniques, which would be a new and interesting addition to the existing jutsu in the Naruto world. And sometimes, there's a plotline where the Ice Dragon Slayer has a hidden past related to an ancient clan in the Naruto universe that gives them special powers or a mission to fulfill.
The world - building is another aspect. Writers often blend the ninja world of Naruto with the demon - infested world of Demon Slayer. They create new landscapes, rules, and cultures that are a blend of both universes, which is really engaging to read about.