Who could be the main antagonist in a 'naruto controls darkness fanfiction'?

It could be an ancient evil that has been lurking in the shadows for ages. Maybe a dark spirit that was sealed away long ago and is now breaking free, and Naruto has to control the darkness within himself to fight it.

There could be a powerful shinobi from within Konoha who is jealous of Naruto's unique ability to control snow. This shinobi might secretly work against Naruto, trying to undermine his progress and steal the power for himself.

It could be Orochimaru. He's always been interested in new and powerful jutsus. He might see Naruto's shadow - controlling ability as something he wants to steal or use for his own evil purposes.

It could be the Hidden Leaf Village itself. If the village turns against Naruto through false accusations or unjust treatment, it becomes the force that drives him to the dark side. The elders or some of the more conservative ninja in the village who oppose Naruto's unorthodox ways could be the face of this antagonism.

It could be an old ninja who was once banished from Konoha for using dark jutsu and now wants revenge. He might see Naruto as a symbol of the village he hates and tries to corrupt him by luring him into the darkness.

It could be Orochimaru. He has always been interested in power and has no qualms about using dark methods. He might see Naruto as a perfect vessel or a tool to further his own dark plans, and through his manipulations, Naruto starts to be consumed by darkness.

It could be a rogue ninja from within Konoha who has embraced the 'darkness' fully and wants to reshape the village according to his own twisted ideals.

It could be a rogue Huntsman who wants to use Ruby's power to control Grimm for his own evil purposes. He might believe that with the Grimm under his control, he can rule over Remnant. He would then be constantly trying to kidnap Ruby or figure out the secret behind her power, and would oppose team RWBY at every turn.

It could be another character who also has some time - related powers but uses them for evil. This character might try to steal Percy's time - controlling ability or use their own powers to disrupt the timeline for their own gain.

In 'naruto controls the darkness' fanfiction, it could also be that Naruto is exposed to a dark energy source accidentally. This energy starts to influence his thoughts and actions in negative ways at first. But being Naruto, he doesn't give in. He uses his strong willpower and the positive relationships he has with his friends like Sasuke, Sakura, and others to find a way to control this new dark power. He might have to face some of his own demons from his past, like the loneliness he felt as a child or the times he failed to protect his friends, and use these experiences to better understand and control the darkness within him.