I can't provide any content that involves political sensitive topics or violates ethics. At the same time, according to the relevant laws and regulations, I cannot provide any novels or articles related to violence, sex, horror, and other content.
I strongly recommend Naruto in One Piece World to you. It tells the story of a college student who likes to watch movies, anime, and play games. He transmigrated into the Naruto world and became a villain. He didn't have a cheat code, but he relied on the Naruto storyline that he was familiar with. He dodged the attacks of the main characters in one disaster after another and finally became an elite Chuunin. However, in the end, he was actually killed by Nine-Tailed's big butt when he attacked the village. What was even more deceptive was that he had transmigrated to the world of One Piece and had a speechless system. The plot of this novel was wonderful, and the characters were vivid. It was very worth reading. I hope you like this fairy's recommendation. Muah ~😗
Kaguya could be an interesting choice. She is extremely powerful and has a complex backstory. Her motives were initially self - serving and evil. If she were somehow resurrected or a situation where Naruto had to interact with her in a different time - line, it could make for a great fanfiction. Naruto's ideology of peace and friendship could clash and then potentially influence her.
Betrayal is a common theme. Naruto might be betrayed by his friends or the village he once trusted, which pushes him towards villainy. Another theme is power corruption. His great power could be corrupted by external dark forces or his own inner turmoil. For example, if he's constantly ostracized despite his good intentions, he might start to use his power in a more self - serving and harmful way.
Orochimaru could be a likely main villain. He has always been interested in Naruto's power and body. Maybe he finally devises a plan to kidnap Naruto and use his body for his own reincarnation experiments.
It could be Orochimaru. He might be interested in Ino's unique abilities, like her mind - control jutsu, for his own evil experiments. So he kidnaps her, and Naruto has to fight against Orochimaru's snake - like techniques to save Ino.
Maybe the plot could revolve around Naruto getting influenced by a powerful and evil entity. This entity could corrupt his mind, making him believe that the only way to achieve true peace is through domination. So, he would begin to gather power, using his skills and charisma, but for the wrong reasons. He would form his own group of followers, who also believe in his new 'world order' ideas, and start a war against the existing shinobi villages.
It could be Orochimaru. He might be interested in stealing the exosuit to enhance his own powers and immortality research. He could see the exosuit as a new way to achieve physical enhancements beyond what his current jutsu can do.
Another possibility is that the main villain could be a spirit or entity that has been trapped for centuries. It uses its influence to make the Hidden Leaf Village conduct 'experiment 101' on Naruto. The spirit hopes to use Naruto's body as a vessel to be reborn into the world and wreak havoc. So it manipulates the events and people involved in the experiment from the shadows.
I recommend Naruto: The Ominous Man. The author is Deer Lord. The main character of this novel is the villain, and the entire story is from the villain's perspective. This is exactly what you need. The storyline was that when Naruto was being strangled by the villain, he heard Dedale talk about the revolution that overturned the destiny, and Naruto eventually became the villain. This book will abuse its owner and make Naruto turn dark. I hope you like my recommendation, Mwah ~😗