Who could be the main antagonist in the 'naruto gets the monkey contract' fanfiction?

Maybe it's an ancient evil that was sealed away long ago and the colossus contract is the key to its release. This evil force would be the main antagonist as it tries to break free and cause chaos in the ninja world. It could be something like a powerful demon that was once defeated by the first Hokage but is now on the verge of coming back because of the colossus contract. Naruto would have to stop it with the power of the colossus.

It could be Sasuke. I know they are friends in the original, but in this fanfiction, Sasuke might turn against Naruto for some reason. Maybe he becomes jealous of Naruto's newfound power or status.

A new and powerful ninja from a far - off land could be the main antagonist. This ninja has heard of Benihime's power and wants it for himself. He sees Naruto as an easy target at first but soon realizes that Naruto is not going to give up Benihime without a fight. This antagonist could have unique powers that are a challenge for Naruto to overcome while protecting Benihime.

The main antagonist could be an ancient snake spirit that was bound to the contract. This spirit might not like the idea of Naruto, a human, having control over the powers of the contract. So it tries to possess Naruto or drive him insane by constantly whispering dark thoughts and trying to make him use the snake powers for evil. It would be a battle of wills between Naruto and this malevolent spirit.

In the 'naruto gets the monkey contract' fanfiction, Naruto could experience a whole new level of power and adventure. Firstly, the monkeys he summons could have different forms and powers. Some might be great at stealth, while others could be powerful in brute strength. This would give Naruto more options in battles. Secondly, the monkey contract might be related to some ancient ninja secrets or prophecies. Naruto could be the key to unlocking these secrets, which would attract the attention of both friends and foes. And finally, his bond with the monkeys could be a heart - warming aspect of the story, showing how he can form connections with different beings in the ninja world.

Sasuke could potentially be an antagonist. With Naruto having the Rinnegan, Sasuke might see him as a threat to his own power and goals. This could lead to a new rivalry between them, different from their previous one.

It could be Orochimaru. He has always been interested in power and Naruto's unique abilities. With Naruto sealed away, Orochimaru might see it as a chance to steal whatever power Naruto had or use his absence to further his own evil plans in the ninja world.

It could be a hidden group within Konoha that was behind Naruto's banishment. They might be afraid of his growing power and influence. This group could work in the shadows to stop Naruto from ever returning to Konoha and regaining his status.

It could be Orochimaru. He's always interested in powerful artifacts, and the mask Naruto gets would be no exception. Orochimaru would likely try to steal the mask from Naruto to add to his collection of powerful items and use its power for his own dark experiments.

A rogue ninja who wants to steal the power of the contract for his own evil purposes could be the main antagonist. He might be jealous of the connection between Sakura and Itachi and wants to break it to gain the abilities they could potentially unlock together.