Who could be the main antagonist in a 'naruto is a saiyan fanfiction'?

There could be a being from another dimension, a creature that feeds on chaos and destruction. It senses Naruto's new power as the Saiyan God of Destruction and wants to consume him to become even more powerful. This being would be extremely difficult to defeat as it has unique abilities that are not known in either the Naruto or Saiyan universes.

It could be a powerful ninja who has made a deal with an otherworldly force to gain powers to match Naruto's. This antagonist might be jealous of Naruto's unique heritage and wants to prove that pure ninja power is superior. So, he uses dark magic or forbidden jutsu to become a formidable foe.

There's a possibility that an evil wizard or scientist who has been studying the Saiyans creates a new form of threat specifically targeting Chichi. This antagonist could be trying to use Chichi's new Saiyan powers for his own evil purposes, like using her to open a portal to a dangerous dimension or to extract the power from her to create a super - weapon.

It could be someone from the Naruto universe who doesn't like Naruto's newfound fascination with Aku. For example, Danzo might see Naruto's interest in Aku as a threat to the stability of the village and try to stop Naruto from further exploring Aku - related things. So, Danzo could be the main antagonist in this case.

It could be a young Saiyan who was sent to the Naruto universe as part of some sort of experiment by the Saiyan race. They are neglected because they seem so different from the ninjas. They would be the main character as they struggle to find their place and purpose in this new world.

It could be a rogue Saiyan from a forgotten part of the Saiyan history. This Saiyan might have a grudge against the Z - fighters and their descendants, like Pan. He could have developed his own version of the Super Saiyan 4 power in a more evil way and wants to prove his superiority by defeating Pan.

Maybe a new character could be introduced as the main antagonist. This character could be from a hidden village that has been secretly observing Naruto's growth. They realize his potential as a weapon and plan to steal his power or use him to start a war against other villages.

Krampus himself could be the main antagonist. Since he is a figure known for punishing the naughty, his actions in the Naruto world might be seen as unjust. He could be going after ninjas without really understanding their motives, causing a lot of trouble for the main characters.

It could be a rogue ninja who also has somehow acquired bankai - like powers. This antagonist might be jealous of Naruto's newfound abilities and wants to prove that he is the stronger one. So he starts causing chaos in the ninja world, challenging Naruto at every turn.

It could be a rogue ninja who wants to disrupt Naruto's business to gain power. Maybe he's jealous of Naruto's success and popularity in the business world. He could try to steal Naruto's business secrets or sabotage his operations.