Percy Jackson is likely still one of the main characters. After all, he's the central figure in the original series. And Annabeth might also be there, as she's always been by Percy's side.
Well, one interesting concept could be the new power dynamics. With new gods introduced, it might change how Percy and his friends interact with the divine world. Maybe the new gods have different rules and values compared to the old ones.
Perhaps a fanfiction where the New Gods create a sort of competition for demigods. Percy enters this competition and discovers that there are rules he's not used to, and he has to use his wits and skills in new ways to win. And along the way, he makes some unexpected allies among the new gods.
Maybe Percy unknowingly breaks some ancient and very strict laws of the Gods. For example, he might interfere with some sacred rituals or places that are off - limits to mortals, even demigods like him. In the fanfiction world, the Gods could be very unforgiving when it comes to such violations and decide to kill him as a result.
Yes, it is quite popular. Some fans like to explore alternate storylines where Percy takes extreme actions like this. It adds a new level of drama and reimagines the power dynamics in the Percy Jackson universe.
Another way is to have the New Gods bring in a new type of magic or technology to the Percy Jackson universe. This could change the dynamics of how demigods operate. For example, if the New Gods introduce a magic that can enhance a demigod's weapon but at a cost, Percy would have to decide whether to use it or not.
Well, in some fanfictions, Zeus and Poseidon have a 'divine argument' over who has the better beard. It's really silly but makes for a great read. Also, Aphrodite trying to give makeovers to the other gods against their will can be extremely humorous. For example, she once tried to put makeup on Ares in a fanfic, and Ares' angry reaction was a riot.
In fanfiction about Percy Jackson Gods' Promises, one common aspect is the exploration of how the gods' promises shape the characters' fates. For example, Percy might be directly or indirectly affected by a promise made by Zeus or Poseidon. These promises often add an extra layer of complexity to the story, as they can be broken or fulfilled in unexpected ways.
Another theme is the creation of new quests. Fanfiction writers often come up with unique quests for Percy and his friends. These quests can involve different mythologies or new challenges that are not in the original books. For instance, a quest that takes them to a hidden realm full of forgotten gods.
One great 'Percy Jackson and the Gods Fanfiction' is 'The Lost Hero's Return'. It has an exciting plot where Percy comes back after being lost in a mysterious realm. The author does a wonderful job of staying true to the characters' personalities from the original series.