Perhaps Percy discovers a hidden workshop of Hephaestus that holds secrets about his past and also contains a special item. He has to figure out how to use this item, which is tied to Hephaestus' power, to defeat a group of monsters that are immune to normal weapons. As he delves deeper into the role of the champion, he also has to deal with the jealousy of other Hephaestus' children who think he doesn't deserve the title.
One plot idea could be Percy having to use Hephaestus' skills to repair a powerful, ancient weapon that is the key to saving the demigod world from a new threat. Another could be Percy competing in a Hephaestus - inspired crafting contest among the demigods to prove his worth as the champion.
One idea could be that in the fanfiction, Hephaestus discovers Aphrodite has a special interest in Percy Jackson. Hephaestus, being the god of the forge, could create some sort of magical item that ties Percy to their story. Maybe it's a charm that makes Percy visible to the gods' love affairs in a way he wasn't before, and he has to navigate the complex relationship between Hephaestus and Aphrodite while also dealing with his own demigod duties.
One plot idea could be that Percy Jackson gets caught in the middle of a feud between Aphrodite and Hephaestus. Maybe Hephaestus asks Percy to retrieve something that Aphrodite has stolen from him, which leads Percy on a wild adventure filled with Aphrodite's love - related traps and Hephaestus' mechanical defenses. Another idea is that Aphrodite decides to use Percy as a pawn in her game to make Hephaestus jealous, creating all sorts of romantic chaos for Percy. Or perhaps Percy discovers a secret pact between Aphrodite and Hephaestus that has far - reaching consequences for the demigod world, and he has to figure out how to deal with it.
One idea could be that Percy has to seek Hephaestus' help to repair a powerful weapon that is key to defeating a new threat. Maybe the weapon was broken in a battle against a mysterious monster. Another plot could involve Hephaestus tasking Percy with retrieving a special metal from a dangerous location, like the heart of an active volcano, in order to create a new, even more powerful weapon for the demigods. And perhaps there's a sub - plot where Hephaestus' children are in some sort of trouble and Percy has to team up with them to solve the problem.
One idea could be Percy discovers a long - lost Hephaestus - made weapon that has special powers. It could be a sword that can cut through any material, but it has a mind of its own and Percy has to figure out how to control it while also dealing with other monsters that are after the weapon.
One idea could be Percy having to travel through different time periods to collect artifacts that can stop Chronos' evil plans. He might visit ancient Greece and interact with the gods in their prime. Another could be Percy facing off against his past and future selves, who are being manipulated by Chronos.
One idea could be Percy having to master the power of Aether in a new realm filled with strange creatures. He might face challenges that test his loyalty to his friends and his understanding of this new power. Another plot could involve Percy using Aether to save Camp Half - Blood from a threat that normal demigod powers can't handle. Maybe he has to make a sacrifice to fully embrace his role as the Champion of Aether.
One idea could be Percy having to learn the unique skills of Hephaestus' cabin, like forging magical weapons. He might struggle at first because he's used to his own powers. Another could be him having to deal with the other Hephaestus kids who are initially jealous of his fame as Percy Jackson but then come to accept him. And he could go on a quest where his new skills as an adopted son of Hephaestus are crucial in defeating a powerful monster.
One idea could be Percy having to face off against a new type of mythical creature in the arena that no one has ever seen before. It would be a test of his skills and quick thinking.
Well, a plot idea could involve Percy being cursed by the fates to forget his own identity. He then has to go on a journey to rediscover who he is while still fulfilling his duties as the champion of the fates. Along the way, he might meet old friends who don't recognize him at first, and he has to prove himself to them. Or perhaps the fates send Percy on a mission to prevent a prophecy from coming true that would destroy the entire demigod world. This would involve him traveling to different mythological places and facing powerful enemies.
One idea could be Percy having to face a series of trials specifically designed by Hera to prove his worth as her champion. For example, he might have to navigate a maze filled with illusions based on Hera's past grudges.