One possibility could be that it's a result of a magical experiment gone wrong. Maybe someone was trying to create a new type of Miraculous or enhance an existing one, and Adrien was accidentally affected, granting him ice powers.
Perhaps it's a gift from a powerful, otherworldly being. In the Miraculous Ladybug universe, there are many mysterious entities. One of these could have seen potential in Adrien and bestowed him with ice powers as a way to help him in future battles or challenges. This could also lead to a whole new storyline where Adrien has to learn to control these powers and understand the intentions of the being who gave them to him.
Perhaps he received some special training from a hidden ice - using master. This master could have taught him the secrets of Ice Release. It might be that this master saw potential in Naruto and decided to pass on this unique ability. Or, it could be related to a new chakra - based experiment. Scientists in the Naruto world might have developed a way to give someone Ice Release, and Naruto was chosen as a test subject for some reason.
You can start by looking on popular fanfiction platforms like Archive of Our Own (AO3). There are often search filters that allow you to specifically search for stories with the 'Adrien has ice powers' theme. Another option is Fanfiction.net, which also has a large collection of Miraculous Ladybug - related fanfics. Just use the search bar and type in relevant keywords like 'Adrien', 'ice powers' and see what comes up.
It could be from a long - lost ancestor. Maybe one of his great - great - grandparents was a powerful fire wizard and the gene has been dormant until now.
Maybe it's some kind of ancient bloodline that was dormant in his family for generations. It suddenly became active in him.
Danny could use his ice powers to create ice shields during battles. This would give him an extra layer of protection against his enemies' attacks.
He could start by simple things like creating ice cubes at will. Then progress to making small ice sculptures, which could later grow into larger and more complex ones. Eventually, he could learn to create ice storms or even entire ice landscapes.
If Naruto had ice powers in fanfiction, it could change the way he battles. He might use ice clones instead of shadow clones. His ice powers could also give him an edge in fighting enemies like Sasuke, who has fire - based attacks. It would add a new dynamic to their rivalry.
One possible reason could be that Marinette has been acting strangely in ways that seem to Adrien to be related to Hawkmoth. Maybe she has been seen in places or at times that are suspicious, like near akuma attacks or where Hawkmoth might be operating from. Another reason could be that someone has been spreading false rumors about Marinette, leading Adrien to believe she has some connection to Hawkmoth.
If Percy had ice powers in fanfiction, it might also affect his relationships. His friends would see him in a new light, perhaps with a bit of awe or even some jealousy. He could use his ice powers for fun, like creating ice sculptures during downtime at Camp Half - Blood. This would add a new dimension to his character and the overall atmosphere of the story.
One interesting Naruto ice powers fanfiction could involve Sasuke somehow obtaining ice powers. Maybe through a forbidden jutsu experiment gone wrong, he now has the ability to create ice sculptures that can also be used as weapons. For example, he could make ice shurikens that are much more powerful than the normal ones and have a freezing effect on the opponent.