Who could be the main antagonist in 'ultimate sharingan naruto fanfic'?

It could be a rogue ninja who has also obtained a corrupted form of the Rinne Sharingan. This antagonist would use the power for his own gain, causing chaos in the Naruto world. He might be seeking to overthrow all the existing shinobi villages and establish his own rule, using the unique abilities of the Rinne Sharingan like the ability to create powerful illusions that can affect entire villages at once.

It could be Sasuke. Since the fanfic has 'Sharingan' in the title, Sasuke, who is well - known for his Sharingan abilities in the original Naruto series, might be one of the main characters.

Danzo could be a great antagonist. He's always been power - hungry and has a history of using underhanded methods. In a fanfic, he could see the power of the Sharingan warrior as a threat to his plans for Konoha. He might try to either eliminate the warrior or manipulate them for his own gain.

It could be Orochimaru. He has always been interested in powerful abilities like the Sharingan. In this fanfiction, he might try to steal Naruto's newly acquired Sharingan for his own experiments and to increase his power even more.

It could be Orochimaru. Since he has always been interested in obtaining powerful abilities, he might see Naruto with the Sharingan as a threat and try to take it for himself.

Another possibility is an ancient evil that has been awakened by the presence of Naruto's new power. The Eternal Mangekyou Sharingan might emit some sort of energy that disturbs an old seal or something. This ancient evil could be a powerful demon or a long - forgotten ninja with dark powers. It would be a huge threat not only to Naruto but also to the entire ninja world, and Naruto would have to use his new - found power along with his usual determination to stop it.

Madara Uchiha could be an interesting main antagonist in this crossover. Since he already has strong ties to the Sharingan and was a powerful force in the Naruto series. If he somehow got his hands on the Rinne Sharingan's full power, he would be even more formidable. He could use it to manipulate reality or time, making it extremely difficult for Naruto and his friends to stop him.

It could be a rogue ninja from a forgotten clan who has a vendetta against the Hidden Leaf. This ninja might be seeking to obtain the power of the Mangekyou Sharingan for himself, and sees Naruto as a threat. So, he tries to stop Naruto from fully awakening it and uses all kinds of dark jutsu to attack Naruto and his friends.

A powerful rogue ninja who has discovered a way to control digital creatures could be the main antagonist. This ninja might see Impmon as a key to unlocking even greater power and would stop at nothing to capture him. He could use his knowledge of ninjutsu and his new - found ability to manipulate digital entities to create chaos in both the ninja world and potentially the digital world if he were to gain access to it through Impmon.

It could be a rogue ninja who has mastered parkour to an extreme level. He uses his skills to steal important ninja artifacts and Naruto has to stop him. This antagonist would be very fast and agile, making it difficult for Naruto to catch him using normal ninja techniques.