I'm not sure of specific fanfictions with this exact plot. But you can try searching on popular fanfiction websites like Archive of Our Own or FanFiction.net. Usually, these sites have a good search function where you can type in relevant keywords like 'Percy Jackson' and 'abused Harry Potter' to find what you're looking for.
Well, it's a rather specific type of fanfiction. You might have to dig a bit deeper. One way is to join fanfiction communities or forums related to either Percy Jackson or Harry Potter. There, you can ask fellow fans if they know of any such stories. They might be able to point you in the right direction. Another option is to look for crossovers that involve the darker themes of abuse in the Harry Potter universe combined with the world of Percy Jackson.
One plot point could be Percy using his powers to protect Harry from his abusers. For example, he could create a water shield around Harry when his abusers try to harm him. Another could be Harry teaching Percy some of the magic he knows in return for the protection. This exchange of skills between the two different universes would be really cool.
There are fanfics where the concept of abuse in Harry Potter is used as a contrast to the more nurturing environment in Percy Jackson's world. For instance, Harry could be sent on a quest in the Percy Jackson universe, and during this quest, he slowly overcomes his trauma from the abuse. The story might also involve characters from both universes learning from each other. The demigods could teach Harry about self - acceptance and he could in turn show them the power of magic. This kind of fanfic often delves deep into the psychological aspects of abuse and recovery, while also providing an exciting crossover adventure.
There's also a fanfic where Percy is psychologically abused by a group of jealous demigods. It delves into how he copes with the constant put - downs and isolation. But remember, these are fan - created stories and not part of the official 'Percy Jackson' canon. Reading such stories can be an exploration of different emotional landscapes within the world of Percy Jackson, but they can also be disturbing.
One popular Percy Jackson and Harry Potter slash fanfiction is 'The Crossroads of Destiny'. It combines the magic of the two worlds in an interesting way, with the characters from both series interacting in unexpected ways. The author does a great job of building a new, shared universe for them.
There are fanfictions that blend the settings of these three worlds. Imagine a world where Hogwarts is in the same realm as Camp Half - Blood from 'Percy Jackson' and Forks from 'Twilight'. Characters from all three series interact, and there are new rules and magic systems created. Some fanfictions also explore different time periods in these universes. For example, a 'Harry Potter' fanfiction set in the past during the founding of Hogwarts, with elements of 'Percy Jackson' mythology and 'Twilight' - like supernatural elements added in for an exciting new take on the story.
I also like 'Percy and Harry's Unexpected Encounter'. This fanfiction explores what would happen if Percy and Harry met during a time of crisis in both their worlds. The characters' personalities are well - written, and it's fascinating to see how they work together to overcome the challenges, despite their very different backgrounds and magical natures.
One interesting crossover could be a magical duel between Harry Potter and Percy Jackson. Harry with his wizard spells and Percy with his water - based powers would make for an epic showdown.
I really like 'Merged Realms'. This fanfiction delves deep into how the different powers from Harry Potter and Percy Jackson could co - exist. It has a great story arc where the protagonists from both stories team up to face a common, very powerful enemy. It also does a good job of staying true to the original characters' personalities.
Another interesting one is 'A Shared Destiny'. It takes the idea that there is a greater force at work that links the fates of the characters from both series. The author does a great job of bringing in the unique aspects of each world. For example, the magical creatures from Harry Potter and the Greek gods' influence from Percy Jackson are both integral parts of the story, making for a really engaging read.
There's 'Percy in the Wizarding World'. In this fanfiction, Percy somehow gets transported to the Harry Potter universe and everyone there mistakes him for a strange kind of wizard. The author does a great job of showing Percy's confusion and how he tries to adapt to this new world while still having his demigod powers. It's an exciting read with lots of action and humor.