Who could be the main antagonist in a 'Naruto Death Parade' fanfiction?

It could be Orochimaru. Even though he's had his moments of redemption, he might relapse into his old ways. He could see Naruto's 'death' as an opportunity to carry out some evil plan that Naruto would have stopped. Maybe he wants to use Naruto's death to create chaos and then take advantage of the power vacuum in the ninja world.

It could be an evil shinobi who has somehow managed to control or manipulate the God of Death's powers for his own malicious purposes. This shinobi might use the power to create chaos in the ninja world, like raising the dead and making them fight against the living.

It could be a powerful rogue ninja who wants to use Naruto's new - found 'harbinger of death' status for his own evil purposes. Maybe he believes that Naruto can lead him to powerful and dark artifacts that are only revealed during times of death and destruction.

It could be a rogue ninja from another village who has a long - standing grudge against Naruto. Maybe this ninja has been plotting for years to take revenge on Naruto and when Naruto fakes his death, he starts to target Naruto's friends and family instead, thinking it will draw Naruto out.

Another possibility is that the main antagonist is a group. It could be a secret organization that Naruto discovers is plotting something big. Since they are so powerful and well - connected, Naruto fakes his death to infiltrate them and expose their plans from the inside.

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 ancient evil that has been sealed away for centuries but has now found a way to use the concept of the Death God to break free. This entity was once a powerful ninja who turned to dark magic and now wants revenge on the modern ninja world. It could be a very powerful foe for Naruto as it has knowledge of old and forgotten jutsus.

It could be an ancient dark ninja who wants to use Naruto's new 'avatar of death' powers for his own evil purposes. This ninja might have been researching death - related jutsus for years and sees Naruto as the key to his ultimate power.

Perhaps Naruto enters the Death Parade world in search of a lost comrade. He teams up with the arbiters, reluctantly at first, when he realizes that they have some knowledge about where his friend might be. Along the way, he shows them the power of friendship and loyalty that he has learned in the Naruto universe, and they in turn show him the complex nature of the afterlife in the Death Parade world.

It could be a new, powerful ninja who has a vendetta against Naruto. This antagonist might be jealous of Naruto's popularity and power, and wants to take over the Hidden Leaf Village.