One popular theme could be Percy's adventures within the Olympic realm. Maybe he discovers new powers or meets unique Olympic deities. Another theme might be his relationships with other characters in this fanfiction's take on the Olympian world, like forming alliances or facing rivalries.
Often, a common theme is Percy's struggle to fit into the Olympian society. He's from a different world in the original stories, so adapting to the rules, hierarchies, and cultures of the Olympians can be a big part of the fanfiction. It could also involve themes of heroism, where Percy has to save the Olympian world from some sort of threat.
Percy himself is obviously a must - include. His powers and his connection to Poseidon make him a central figure. Annabeth is also very popular. Her intelligence and her relationship with Percy add a lot of depth to the story. Grover is another great character. His loyalty and his role as a satyr can bring in some interesting elements, like his ability to sense danger and his connection to nature.
Friendship is a very common theme. Fanfics often show the strong bonds between Percy and his friends, like how they support each other through tough times at Camp Half - Blood. For example, they might have a scene where Percy's friends cheer him up when he's feeling down about a recent quest.
Well, you could write a fanfiction where Percy loses his memory and has to rediscover his powers and his place among the demigods. Or perhaps a story about how the minor gods in the Percy Jackson universe form their own alliance because they feel overlooked by the Olympians. You could also create a fanfic that focuses on Annabeth's journey if she was separated from Percy and had to fend for herself in a dangerous situation.
It could be an ancient deity that was banished long ago. Maybe a primordial god or goddess who was considered too powerful or too dangerous for the other Olympians. For example, it could be Erebus, the god of darkness.
Well, perhaps Percy has to go through a series of trials. He might need to prove his worthiness to the Olympians. Maybe he has to battle some mythical creatures that are threatening the Olympian realm. And in the end, he gains the recognition and powers of an Olympian.
Aside from Percy, Jason Grace is often included. He has his own set of powers and experiences from being a Roman demigod, which can create great conflicts and alliances in fanfiction. Piper McLean is also a great character to add. Her charm - speak ability can be used in really creative ways in a story. And of course, Leo Valdez with his mechanical skills and humorous personality can add a lot of fun and action to the fanfiction.
One idea could be Percy going on a quest to find a lost artifact that has the power to control the weather in the Olympian realm. This would put him in conflict with some of the gods who want to use it for their own purposes.
Percy Jackson himself is very popular. He's the main character of the series, so fans often like to continue his story, explore his relationships further, or put him in new and challenging situations. His powers and his journey are really interesting to build on.
A common theme is alternate universes. Fans create their own versions of the Percy Jackson world where things are different. For instance, what if Percy was a Roman demigod instead of a Greek one? Also, relationships between characters are a big theme. This can be friendships, rivalries, or romantic relationships, but all within the bounds of a family - friendly setting.
One major theme is the expansion of the Percy Jackson world. This can include creating new mythological creatures or exploring uncharted areas of the existing world. Family relationships are also a big part of it, especially the complex relationships between demigods and their godly parents. And of course, there's the theme of heroism, with demigods rising to face great challenges.