Well, perhaps the Percy Jackson fan would introduce Harry to the world of Greek mythology. Harry might be trained in combat styles different from what he learned at Hogwarts, like using a celestial bronze sword. He could also be exposed to demigod powers and might start to see magic from a whole new perspective, with a blend of Greek magic and Hogwarts' magic.
If Harry Potter was adopted by a Percy Jackson fan in fanfiction, it could lead to some really interesting crossovers. The fan could try to find ways to connect the magic of the wizarding world with the powers of the demigods. For example, they might explore if Harry's Patronus could have a connection to a Greek spirit or deity. Also, Harry could be influenced by the values of the demigods, like loyalty to friends and courage in the face of great danger. This could change the way he approaches problems in the wizarding world, and he might bring some new ideas and techniques back to Hogwarts when he has to face Voldemort and his Death Eaters.
His life would change drastically. He'd be exposed to different mythologies. Instead of just the wizarding lore, he'd learn about Greek gods and monsters. His combat skills might improve as he learns demigod - like fighting.
A possible plot could be centered around a new threat that targets both their worlds. Harry and Percy, as brothers, must unite their friends from Hogwarts and Camp Half - Blood. They would have to combine their different combat styles, with Harry using spells like Expelliarmus and Percy using his sword. Along the way, they would also deal with family drama, like how their different parents' legacies impact their relationship.
One interesting plot could be Percy's new relationship with Hestia. Since Hestia is the goddess of the hearth, Percy might learn a different kind of warmth and family from her. Maybe she teaches him some ancient secrets related to the hearth that give him new powers or ways to defend himself. Also, how Percy interacts with other gods and demigods in this new situation would be exciting to explore. For example, some might be jealous of his special relationship with Hestia while others might try to use it for their own gains.
Well, the plot could start with Harry being found by the mafia after some sort of accident or escape from the Dursleys. The mafia, seeing his potential and his lack of a proper family, decides to take him in. They would train him in their ways, which could include things like combat and stealth. Harry might then have to navigate between the mafia's underworld and the wizarding world, trying to keep his two lives separate while also using his new skills to fight against the Dark Lord.
Well, it could be really wild. Maybe Hellboy would teach Harry some of his unique combat skills. Harry might grow up with a different perspective on magic and the supernatural world, influenced by Hellboy's more physical and brute - force approach to dealing with threats.
Well, he might grow up with a very different cultural influence. Maybe he'd be into American football instead of Quidditch at first. He could also have a more outspoken and confident personality, like many American characters are often portrayed.
Well, in such a fanfiction, the plot might involve Hecate seeing Harry's potential not just as a wizard but as someone with a special destiny related to the magical world at large. She adopts him and begins to train him in her own brand of magic. This could lead to conflicts with the Ministry of Magic as they might see Harry's new powers as a threat. Also, Harry could use his newfound knowledge to better understand the Horcruxes and find a way to defeat Voldemort more quickly.
Well, one possibility is that Harry would grow up with a very different set of values. The Malfoys are known for their pure - blood supremacist views. But perhaps, deep down, Harry could influence them to be a bit more accepting. He might learn dark magic quicker than in the original story, but also struggle with his own sense of right and wrong as the Malfoy values clash with what he feels inside.
The settings are different. Harry Potter is set mainly in the UK, at Hogwarts School of Witchcraft and Wizardry and other wizarding locations. Percy Jackson is set in modern - day USA, with a lot of action taking place at Camp Half - Blood. Also, the magic systems vary. In Harry Potter, there are spells, potions, and magic wands. In Percy Jackson, the demigods have powers related to their godly parentage like Percy can control water because his father is Poseidon. So they are clearly not related in a fanfiction way.
A possible plot could be that a powerful Godlingg artifact is discovered that has the potential to destroy both the wizarding world of Harry Potter and the demigod world of Percy Jackson. Harry and Percy, along with their friends, must race against time to find and secure the artifact before it falls into the wrong hands.