The main antagonists could be other ninja clans or villages. Since Naruto is godlike and without family protection, they might see him as an easy target or a threat to their power. They could send their strongest ninjas to take him down or try to manipulate him into working for them.
It could be his own family members who abandoned him. They might come back as antagonists, trying to stop Naruto from reaching his full potential or causing trouble for him out of envy or regret. Maybe they have joined a dark force and are now working against him.
His family members themselves could potentially be antagonists in a sense. If Naruto is rejecting them, there could be some family members who try to stop him from leaving or try to change his mind forcefully. They might see his rejection as a threat to the family's reputation or unity.
Perhaps there are dark forces from another dimension. These forces might be attracted to Naruto's power and want to either steal it or destroy him to prevent him from using it against them. They could be powerful demons or sorcerers with their own motives.
Another possibility is that the main antagonists could be the leaders of the other ninja villages. They might view Naruto's godlike and rogue status as a danger to the balance of power among the villages. So, they could form an alliance against Naruto, leading to a lot of political intrigue and conflict in the story.
In this fanfiction, the main antagonists might be a group of dark chakra - users. They are jealous of Naruto's godlike powers and want to take over the empire for their own evil purposes. They could be using dark magic to corrupt some of the people in the empire, turning them against Naruto. There might also be some power - hungry politicians within the empire who are not satisfied with Naruto's leadership and want to seize power for themselves. They would plot behind the scenes to bring down Naruto and take over the reins of the empire.
Maybe it could be other ninja clans who are jealous of Naruto's newfound sword bloodline. They might see it as a threat to their own power and status in the ninja world.
Well, in this fanfiction, the Akatsuki could be the main antagonists. They would view Naruto's godlike powers as a major threat to their goals. Since Naruto has been trained by Shendu, his abilities would be unpredictable and extremely powerful. They might band together to try and take Naruto down. Additionally, there could be some ancient demons or spirits that are awakened by Naruto's new powers and they see him as an intruder in their realm, so they become antagonists as well. They would use their own dark magic and powers to oppose Naruto.
The village elders could be the main antagonists. They might see Naruto's godlike powers as a threat to their traditional way of ruling the village and decide to get rid of him. Another option could be a secret organization within the village that wants to use Naruto's power for their own evil purposes and when he refuses, they turn on him.
One possible main antagonist could be a powerful being that controls the different dimensions and sees Naruto's hopping as a threat to his order. Another could be an evil version of Naruto from another dimension who wants to stop our Naruto from spreading his 'good' influence. Maybe a group of rogue dimension - travelers who are causing chaos in different dimensions and Naruto has to stop them.
In this fanfiction, perhaps Naruto's family abandons him because they believe he's a danger due to his godlike abilities. He might start as a broken character, but as the story progresses, he could use his powers to protect those who accept him, like his friends in Konoha. He would have to overcome the emotional trauma of being abandoned and rise above it all.
Maybe there's a rogue ninja who has developed a new and dangerous jutsu that can counter Naruto's powers. This ninja wants to prove himself as the strongest by defeating Naruto and taking over the bijuu's power. He might be jealous of Naruto's newfound status and the respect he gets from the other ninjas.