One idea could be Percy having to mediate between Zeus and Hades during a major feud. Since he's the son of both in this fanfiction, he has a unique connection to them. He could use his powers and his knowledge of both of their domains to try and broker peace.
In this fanfiction, there might be a lot of focus on Percy's relationship with the other wolves in Lupa's pack. He could learn their ways of survival, their hierarchy, and how to be a part of their community. This would be a great way to explore his adaptability and growth.
Annabeth Chase might also be an ally. Her intelligence and strategic thinking could be valuable assets for the son of Hades. She could help him plan his moves, especially when dealing with the complex politics among the demigods and gods.
One interesting plot twist could be Percy finding out he has a hidden power related to Hades' realm that he didn't know about before. Maybe he can control a special type of underworld creature that no one has ever seen. Another could be Percy having to face off against a false heir to Hades' throne who is trying to frame him for crimes in the underworld.
Well, of course, Percy Jackson himself often makes an appearance. He could be a mentor figure to the adopted son, guiding him through the ropes of being a demigod. Annabeth is also common, perhaps helping the adopted son with her wisdom and knowledge of the mythological world.
The setting of the story might shift a bit. Instead of always being at Camp Half - Blood or on quests related to the Greek gods, Percy could be in the territory of the wolves. There could be new threats and challenges there, like rival wolf packs or ancient enemies of Lupa. And all these elements would make for an exciting and different take on the Percy Jackson universe.
One common theme is the struggle with identity. Since Percy's parentage is so different from the original, he has to figure out who he really is. Another theme is power. With Hades and Artemis as his parents, he could have a whole new set of powers to discover and control. And there's also the theme of acceptance, both from himself and from the other characters in the Percy Jackson universe.
One possible plot could be Percy struggling with the duality of his parentage. He might face discrimination from both the children of Hades and Poseidon. For example, the children of Poseidon could see him as a threat because of his connection to Hades, and vice versa. He could then go on a journey to prove that his dual heritage doesn't define him, but rather gives him unique powers to protect the world of the gods and mortals.
Common themes include acceptance. The OC has to find a way to be accepted by the other demigods who may be wary of him because of his father. Redemption is another theme sometimes. Maybe the OC has made mistakes or has been associated with 'evil' because of Hades, and they strive to prove themselves. And the theme of fate also pops up often. They wonder if their destiny is set because of being the son of Hades or if they can change it.
There are definitely some. However, the quantity might be less compared to more common pairings in the Percy Jackson fanfiction world. One great aspect of these fanfics is how they often blend the themes associated with Hades and Hestia. For instance, Percy might struggle with the duality of his nature - the brooding, dark side from Hades and the nurturing, home - like quality from Hestia. It makes for a very interesting read if you can find well - written ones.