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.
In this fanfiction, it could be that Percy is chosen for a special task by the existing Olympians. They see his potential not just as a hero but as someone who could join their ranks. So he gets trained in Olympian magic and lore, which is very different from what he's used to. He has to learn how to control new powers and also deal with the politics among the Olympians.
In this kind of fanfiction, one possible plot could be Percy having to deal with the politics among the Olympian gods. He might try to bring about changes, like making the gods more involved in mortal affairs in a positive way. For example, he could convince them to be more proactive in protecting the environment which is being damaged by humans. Also, Percy would probably have to face new enemies. Since he's now an Olympian, he could attract the jealousy of some minor gods or ancient monsters who see him as a threat to the established order.
The Titans could be the main antagonists. They might oppose Percy's ascension to Olympian status because they see it as a threat to their own plans of overthrowing the Olympians.
The Titans might still be a threat. Even though they were defeated before, they could have some remnants or followers who don't want Percy to become an Olympian because it would strengthen the Olympian side even more.
Well, it could be about Percy facing a new and powerful threat that even the Olympians can't handle easily. Maybe he discovers a hidden 13th Olympian who has been locked away for centuries and now is causing chaos.
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.
In this 'percy becomes a primordial fanfiction', the plot could involve Percy being thrust into a world where the rules of the original story no longer apply. As a primordial, he could have the ability to shape reality. He may start to question his own identity and purpose, and there could be a battle for control over his new powers between different factions.
In the 'Percy becomes famous fanfiction', it could be that Percy enters a grand tournament. He faces many tough opponents but manages to win through his wits and strength. His victory in this high - profile tournament makes him a well - known figure. People start to idolize him, and his name spreads far and wide. He also uses his new - found fame to advocate for positive changes in his community.
In the fanfiction, Percy might be chosen by some divine force to become an angel. As an angel, he may have to face the challenges of living in the celestial realm while still having ties to the mortal world. He could struggle with his new identity and the responsibilities that come with being an angel, such as guiding lost souls or fighting against evil forces that threaten the balance between the two worlds.
Well, perhaps Percy could start as a normal human or character and then through some strange event, like a scientific experiment gone wrong or a magical encounter, be transformed into a Zerg. He might then have to adapt to the Zerg's hive - mind society, learn their ways of war and survival, and face challenges from both the Zerg world and his former world which now sees him as a threat.