Well, a cool plot for a 'Naruto ice ninja fanfic' might be that the ice ninja is actually a long - lost member of a clan in Konoha. Their ice powers were suppressed for some reason in the past. Now, they return and have to relearn how to control their powers while also dealing with the suspicion of some of the Konoha villagers. Naruto could be the one to help them gain acceptance and together they face off against an enemy who wants to steal the ice ninja's power.
In a 'Naruto ice ninja fanfic', perhaps the ice ninja is a part of a prophecy. The prophecy states that an ice - wielding ninja will either save or destroy the ninja world. Naruto initially doubts the ice ninja's intentions. As they go on adventures together, they discover that there are dark forces trying to manipulate the ice ninja into fulfilling the 'destroy' part of the prophecy. They must then fight against these forces and prove that the ice ninja will be the one to save the world.
One idea could be an ice ninja from a hidden village in the far north coming to Konoha for a ninja exchange program. They could introduce unique ice-based jutsus to Naruto and his friends, like creating ice clones that are more durable than regular shadow clones. Another plot could involve an ice ninja villain who is trying to freeze the world and Naruto has to learn a new fire - ice combined jutsu to stop them.
A cool plot could be that an ice ninja has the power to freeze time within ice. The Akatsuki wants to capture this ninja to use their power for their own evil plans. Naruto and his team must protect the ice ninja and figure out a way to stop the Akatsuki from getting their hands on this dangerous ability.
Maybe a fanfic where all the characters are transported to a modern-day world. Naruto would have to adapt to things like technology while still trying to use his ninja skills. He could end up using his shadow clones to do multiple jobs at once to earn money and also keep his ninja training going.
One idea could be a medical ninja who discovers a new healing technique that has side effects that no one expected. This could lead to a race against time to find a cure while also dealing with the political implications within the ninja villages.
One idea could be a new character with ice style powers arriving in Konoha. This character could initially be seen as a threat but turns out to be an ally against a common enemy. Maybe an ancient ice - based evil is awakening, and only those with ice style can help stop it.
Maybe in the fanfic, there is a special mission where Naruto and the Ninja Gaiden characters need to retrieve a powerful and ancient artifact. The Ninja Gaiden side has their own reasons for wanting it, like protecting their village or clan, and Naruto is involved because it has something to do with the balance of his world too. They start off not trusting each other but as the adventure progresses, they form a strong bond.
Well, perhaps in the fanfic, the sky ninja are descendants of an ancient clan that was banished from the land long ago. They live in floating islands and have a special connection to the sky spirits. A young Naruto discovers their existence and tries to form an alliance with them to face a new and powerful dark force that is emerging, which has the power to disrupt the balance between the land and the sky.
One interesting plot idea could be that in this 'Road to Ninja' fanfic world, Naruto and Hinata get trapped in a genjutsu - created alternate reality where their roles are reversed. Naruto could be the shy one while Hinata is the confident, popular one. They have to figure out how to break the genjutsu together while also realizing their true feelings for each other in this strange new dynamic.
One idea could be to focus on a young and unknown ninja who rises to prominence during the war. They might start with simple missions like scouting but gradually become crucial in major battles, perhaps by using a unique and unexpected jutsu.
One idea could be a rogue ninja who was once a close friend of Naruto but turned due to a misunderstanding. They could have unique powers and be on a mission to prove their own version of justice.
One idea could be a story where the Ninja Wire is used in a new and unexpected way during a major battle. For example, the characters could use it to create complex traps that not only ensnare enemies but also redirect attacks. Another plot could revolve around a young ninja who discovers a unique property of the Ninja Wire and has to keep it a secret while trying to master it.