One way could be that the wizarding world has done something really bad to his family in the past. So, those who raise Harry want to get revenge on the wizarding world by making Harry hate magic. They might brainwash him with false information about magic, like how it corrupts people and leads to chaos.
Maybe some dark wizards who have a vendetta against Dumbledore or the whole Hogwarts system. They think by turning Harry against magic, they can undermine the power of good in the wizarding world. So they take on the task of raising Harry with a hatred for magic.
The plot could start with Harry escaping the Dursleys earlier than in the original. He then roams around, trying to find a place to belong. He might stumble upon some hidden magical secrets in the Muggle world that are related to his parents. As he grows, he starts to attract the attention of both good and bad wizards. Some might want to help him, while others see him as a threat because he's an unknown factor, not following the normal wizard upbringing.
The plot could start with Harry being found by a samurai clan. He'd grow up learning their ways. Then, when he discovers his magical heritage, he has to blend the two worlds. Maybe he uses samurai skills to fight dark wizards.
In this fanfiction, the plot might revolve around Harry's struggle to balance Kreacher's teachings with the values of the wider wizarding world. He could face discrimination from other wizards who are suspicious of his upbringing. Meanwhile, Voldemort might see Harry as an even greater threat because he's been raised by Kreacher. Kreacher, being protective, tries to shield Harry from the Dark Lord, but Harry realizes he has to take a stand. This could lead to a series of battles and adventures where Harry has to prove himself not just as a wizard, but as a person with his own set of beliefs.
One way could be through a plot where Harry discovers some long - hidden secrets about Dumbledore that he feels were manipulative. For example, if he found out that Dumbledore had been using him more than protecting him all along. Harry might then confront Dumbledore publicly in the wizarding world, shaming him for his actions.
One way could be to give Harry the Geass power. So, he could use it to control the actions of Death Eaters or Voldemort himself. He might start to make more strategic and calculated moves like Lelouch, using his new power to outwit his enemies. Another aspect could be in the political side. Maybe the wizarding world becomes more like Lelouch's world with different factions vying for power and Harry has to play a political game as well as fight against the dark forces.
The plot could start with Harry having strange dreams about Shinigami. As he investigates, he discovers that there is a hidden portal in Hogwarts that leads to a realm where Shinigami exist. He and his friends enter this realm, and they find out that there is a dark force in the wizarding world that is related to the Shinigami in some way. They then have to work with some friendly Shinigami to stop this dark force. Along the way, they learn about new forms of magic and the true nature of death from the Shinigami.
The plot could start with a spell gone wrong in Hogwarts that somehow transports a group of Transformers to the wizarding world. The wizards are initially scared but soon realize that they need to cooperate with the Transformers to deal with a new dark force that is attracted to the combination of magic and technology. The story could involve battles, magic - tech hybrids, and new friendships between the two groups.
One way could be to have Harry be adopted by a Mandalorian family. He grows up learning both magic and Mandalorian combat skills. Then, he has to use his combined knowledge to fight against a common enemy that threatens both the wizarding world and Mandalore.
In such a fanfiction, perhaps Harry would grow up with a different kind of magic. Lady Magic could endow him with unique powers. He might have a more in - depth understanding of magic from a very young age, and his relationship with the magical world could be more profound than in the original story.