A really interesting plot twist could be that the cause of the Second Great Ninja War in the fanfiction is not what it seems in the original Naruto lore. Instead of territorial disputes or power struggles, it could be due to an ancient curse that has been awakened. This curse affects the minds of the ninja, making them more aggressive and starting the war. And only a few special characters might be able to figure out the real cause and try to stop it.
How about Hinata? She could be the main protagonist. In the fanfiction, she could be on a journey to prove herself not just as a member of the Hyuga clan but also as a strong ninja in the Second Great Ninja War. She might discover new abilities and play a crucial role in the war, perhaps even saving the day in her own unique way.
In a 'Naruto 5th Great Ninja War Fanfiction', the story could start with a strange phenomenon that begins to disrupt the chakra balance in the ninja world. This is a sign of the approaching war. As the war breaks out, the younger generation of ninjas, inspired by Naruto's heroics in the previous wars, step up to fight. They face off against a coalition of rogue ninjas who are being controlled by a shadowy figure with a vendetta against the established ninja order. Along the way, there are many battles, with each side using new and creative jutsus and strategies.
It could be a long - lost relative of Orochimaru. This person might have been secretly studying Orochimaru's forbidden jutsu and developed even more terrifying techniques. They could be seeking revenge on the ninja world for ostracizing Orochimaru.
Naruto is still extremely popular in these fanfictions. His never - give - up attitude and his growth as a ninja make him a central figure. People love to read about how he overcomes new challenges during the Fourth Great Ninja War.
There could be a new group of villains who emerged from the shadows. They might have been observing the war and learned from the mistakes of previous antagonists. They could be more powerful and cunning, perhaps using new forms of jutsu or technology that were developed during the war. Maybe they are after some ancient artifacts or secrets that were unearthed during the Fourth Great Ninja War.
Perhaps the fanfiction could explore how Naruto deals with the psychological aftermath of the war. He witnessed so much death and destruction. He might have nightmares or struggle with PTSD. Meanwhile, the other villages may approach the Hidden Leaf for help in various ways, such as asking for resources or training methods, which Naruto has to handle while also taking care of his own village.
One interesting plot twist could be that some of the dead ninjas from previous wars come back not as enemies but as allies with a secret mission to end the cycle of hatred. They might have gained new powers or knowledge in the afterlife that can turn the tide of the Fourth Great Ninja War.
One unique plot twist could be that instead of Naruto being the one to finally defeat Madara, it's Sasuke who sacrifices himself to do it. This would completely change the dynamic between the two characters and the overall feel of the story.