Who could be the main antagonist in 'Naruto Returns Two Swords Fanfiction'?

Well, it could be about Naruto coming back with two special swords. Maybe he got them during his time away on some new adventure. He might use these swords to fight stronger enemies in the ninja world, like some new evil organization that has emerged while he was gone.

It could be a new villain who has risen to power during Naruto's absence. This villain might have a vendetta against Konoha or the ninja world in general because of something that happened while Naruto was away.

A new dark entity could be the main antagonist. This entity might have been awakened by Naruto's return from the dead. It could be something that was sealed away long ago and Naruto's return breaks the seal. The entity would then target Naruto and his loved ones to prevent him from getting in its way of ruling the ninja world.

It could be an unknown ninja who has been researching dark and forbidden arts. This ninja accidentally unleashes the Black Death - like plague while trying to gain ultimate power.

Perhaps an old enemy that Naruto thought was defeated has returned, stronger than ever. This enemy could hold a grudge against Naruto and the elemental nations for past defeats and wants revenge.

Perhaps it's an old enemy who has somehow managed to come back stronger. Maybe someone from Orochimaru's old experiments that went wrong, but instead of dying, they gained some dark and powerful abilities. They see Naruto's return as a threat to their plans of world domination, so they target Konoha first. They might be able to control dark chakra in a way that no one has seen before, and use it to create chaos and destruction. They could also have some minions who are equally as powerful and loyal to them, making them a formidable foe for Naruto and Konoha.

It could be a rogue ninja from a neighboring village who has a vendetta against Konoha. This ninja might see Naruto's return as an opportunity to take on the strongest ninja in Konoha and prove his own strength.

A new character could be the main antagonist. This character could be from a far - off land that Naruto has never encountered before. This antagonist has heard of Naruto's power and wants to prove himself by defeating Naruto and taking over the Hidden Leaf. He might have unique powers and a large army at his disposal. He could also be manipulating some of the villagers from the inside to create chaos before making his big move.

The main antagonist could be an ancient evil that has been awakened. Harumi returns to find Ninjago in chaos because of this new threat. She may initially be blamed for the chaos, but as the story unfolds, it becomes clear that the real villain is this ancient evil which the ninjas and Harumi must then team up to defeat.

It could be Orochimaru. He's always been after power and Naruto having the power of two Bijuus would be very tempting for him. He might try to extract the Bijuus from Naruto to use for his own evil purposes.