Perhaps in this fanfiction, Harry is cursed by a powerful dark magic. This curse slowly transforms him into Sauron. At first, he doesn't realize what's happening, but as he changes, his friends notice the difference. He begins to have visions of ruling over vast lands and having ultimate power. He then starts to use his knowledge of magic from Hogwarts to create dark fortresses and enslave those around him, just as Sauron would.
In a 'Harry becomes Sauron' fanfiction, it might start with Harry being disillusioned with the wizarding world. He discovers some ancient magic that has a connection to Sauron's power. As he delves deeper, he becomes influenced by Sauron's will. He could then try to reshape the wizarding world in his image, which is now a dark and tyrannical one. He might even try to bring Middle - earth and the wizarding world together under his rule.
One possible plot could be that Harry Potter grows up in Mordor. Sauron might train Harry in dark magic, but Harry could have an internal struggle as he has an inherent sense of good from his parents. He might try to find a way to use the power he's learning for good, against Sauron's wishes.
It would be really strange. Maybe Harry would have Sauron's powers in the wizarding world and try to take over Hogwarts instead of the One Ring. He could use dark magic and his newfound Sauron - like abilities to intimidate the other students and teachers.
One possible plot could be that Sauron somehow manages to enter the wizarding world. Maybe through a powerful dark magic spell that links the two universes. Harry, being the hero, senses the new and greater evil. He then has to figure out how to defeat Sauron, which is much more difficult than any foe he has faced before. He might have to learn about the power of the One Ring and how to destroy it, all while protecting Hogwarts and the wizarding world from Sauron's dark minions.
The ninja way as it is known would be completely overturned. Naruto has always represented values like friendship, hard work, and never giving up. As Sauron, he would promote values of domination and power over others. Shinobi training might change to focus more on dark arts and subjugation. Younger ninjas would be influenced by this new Naruto, and the future generations of the ninja world would be shaped in a very different and darker way.
Well, one possibility could be that Harry discovers his true parentage as Sauron's son in a very shocking way. Maybe through some dark magic revelation. Then he might struggle with his identity, being a part of the wizarding world that he loves but also having this dark connection. He could face a lot of inner turmoil as he tries to decide whether to embrace his dark heritage or fight against it.
Well, it could be that Harry somehow gets transported to Middle - earth and becomes Sauron. Maybe he has to deal with the power and the evil associated with being Sauron while still having some of his Harry Potter traits, like his sense of loyalty and courage, which could create an internal struggle.
Well, it could be a very dark plot. Maybe Harry is under some dark magic influence that makes him lose his mind and start killing. It would completely change his character from the original story.
If Harry Potter becomes an obscurial in fanfiction, the story could take a very different turn. He might not be as eager to attend Hogwarts as he was originally. The Dursleys might have an even worse time with him because his obscurial powers could lash out. At Hogwarts, teachers would be extremely concerned. Snape, for instance, might be even more critical of him, seeing him as a potential danger. And Harry would have to learn to control this new and dangerous aspect of himself.
One idea could be that the heir of Sauron somehow infiltrates Hogwarts under a false identity. He tries to use the chaos of the wizarding world to his advantage to gather power. Another could be that there is a prophecy that links the heir of Sauron with Harry Potter, and they must either fight or unite depending on how the story unfolds. Or perhaps the heir of Sauron is actually a long - lost relative of one of the Hogwarts professors, which adds a layer of mystery and conflict.
One possible plot could be that the fem Sauron, with her dark powers, infiltrates Hogwarts. She could initially be disguised as a new student or a teacher. Harry Potter senses something is off about her. There could be a series of magical duels and battles of wits between them as Harry tries to expose her true identity while she tries to carry out her own evil plans within the wizarding world.