Well, in 'naruto reaper fanfiction', a cool concept might be the idea of Naruto or other characters having to face reaper - like entities as antagonists. It could bring a whole new level of danger and mystery to the story. These reaper entities could have unique powers and motives that are different from the regular Naruto villains.
One interesting concept could be the fusion of Naruto's ninja world with the reaper elements. Maybe characters from Naruto having to deal with reaper - like powers or entities. For example, Naruto himself might gain the ability to reap souls in some unique way related to his chakra.
One interesting concept is the Grim Reaper having a human form and falling in love. It adds a romantic twist to the usually dark and death - associated character.
One interesting concept could be the clash of different powers. In RWBY, characters have unique abilities like semblances, and the Reaper has its own set of death - dealing powers. A crossover might explore how these powers interact when the two universes collide. For example, how would Ruby's speed and scythe - wielding skills compare to the Reaper's? Another concept could be the meeting of different character personalities. RWBY characters are often young and idealistic, while the Reaper is a more menacing and mysterious figure. Their interactions could lead to some really engaging storylines.
One interesting concept could be different interpretations of the reaper figure. Maybe in the fanfiction, the reaper is not as menacing as in the original idea, but rather a misunderstood being. For example, it could be a reaper who is trying to save souls instead of taking them.
One interesting plotline could be a character with the Reaper Bloodline having to hide their power from the main Naruto characters at first. Maybe they're afraid of being hunted or experimented on because of their unique bloodline.
Perhaps a plot where Naruto makes a deal with the Death Reaper to save his friends. He has to go on a dangerous quest in the afterlife or something like that. It could involve facing his own fears and the dark secrets of the ninja world.
Some fanfictions might explore the idea of Naruto befriending an Espada. This friendship could lead to Naruto learning about different ways of combat and power management from the Espada. It could also result in the Espada having a change of heart due to Naruto's positive influence, and together they could face new threats in the Naruto universe that neither could face alone.
In Naruto fanfiction, the Sharingan is often explored in unique ways. For example, some fanfictions might expand on its ability to not only copy jutsu but also to predict an opponent's moves on a whole new level. Another interesting bloodline concept could be the Uzumaki's massive chakra reserves, and fanfictions may play with how this could be used in different scenarios, like creating entirely new jutsu.
In 'naruto dark naruto fanfiction', the concept of Naruto's doppelganger or 'dark Naruto' is often explored. This could be a manifestation of his repressed negative emotions. It might be that this dark Naruto has its own goals that are contrary to the real Naruto's. For instance, it could want to destroy the Hidden Leaf Village instead of protecting it. And the story could revolve around how Naruto deals with this inner darkness, either by trying to suppress it or, in a more extreme version, merging with it and becoming a different kind of hero or anti - hero.
One interesting concept could be an exploration of Naruto's dark side. It might show how his experiences could have turned him truly evil, like if he had been more influenced by the hatred in the ninja world from the start. Maybe in this fanfiction, he uses his powers for self - gain rather than for the good of the village.