In this fanfiction, Percy could be exposed to different realms and dimensions that are part of Chaos' domain. He might meet some very strange and powerful creatures. Maybe he'll form alliances with them or learn from them to become an even greater hero. Also, his personality could change as he adapts to this new and wild environment under Chaos' care.
Perhaps Percy will be given a new mission or purpose in this fanfiction. He could be sent on quests that are crucial for the balance of the entire multiverse. Since he is adopted by Chaos, he may have a special role to play in preventing some great disasters or in bringing about a new order. And his relationships with his old friends from Camp Half - Blood might become more complex as he gets involved with Chaos' plans.
It's possible that some of Percy's old enemies, like Kronos' minions who somehow survived, might resurface in this fanfiction. They could be trying to stop Percy from achieving whatever goals Chaos has for him. Also, some of the gods might get involved. They could be curious about Percy's new situation, or they might be worried that Percy's new power under Chaos could be a threat to them. And then there could be some mysterious entities from the Chaos - related realms that we haven't heard of before in the original Percy Jackson stories.
Maybe in the fanfiction, Percy is on the verge of death in a battle. Chaos, who has been observing Percy for a while, decides to save him and adopts him. Percy then embarks on a journey in Chaos's realm. He could be trained by powerful beings there and form new alliances. His relationships with his old friends from his previous life might be strained as they don't understand his new situation, but he also gains new friends who are loyal to him because of his connection to Chaos.
In this kind of fanfiction, Percy might gain new powers or a different status. Hera could train him in her own ways, perhaps teaching him more about the divine politics and how to navigate the complex relationships among the gods. He may also have access to resources and knowledge that he didn't have before, which could change his future adventures drastically.
If Percy Jackson were adopted by Artemis in fanfiction, he would likely be protected in a different way. Artemis is a powerful goddess. She could shield him from more threats than he's used to. His personality might also become more reserved like the hunters. He'd be part of a group that values chastity and loyalty to Artemis above all. This would put a strain on his relationships with some of his old friends who might not understand his new lifestyle.
In a fanfiction where Naruto gets adopted by Jiraiya, Naruto's training would be intense and unique. Jiraiya has a lot of unorthodox methods. He could introduce Naruto to some very special and secretive forms of chakra control. Naruto might also learn more about the secrets of the Sage Mode much earlier. With Jiraiya's guidance, Naruto could form stronger bonds with other powerful ninjas that Jiraiya knew. This would give Naruto more allies and a greater understanding of the political and power dynamics in the ninja world.
In this fanfiction, Percy could also have to make difficult decisions about the future of the chaos realm. Should he keep it separate from the mortal and godly worlds? Or should he try to merge it in some way? His choices would have far - reaching consequences for all the realms involved.
Well, he might gain incredible cosmic powers. He could have the ability to manipulate space, time, and matter at will. His appearance might change to something more otherworldly, with a glowing aura perhaps. And he could have a new level of wisdom, seeing the grand design of the universe.
If Percy Jackson joins Chaos in fanfiction, it would likely change his entire perspective. He's used to the world of Greek gods and demigods. But in the realm of Chaos, there are no such clear - cut rules. He could be sent on wild adventures across different dimensions. He might have to face enemies that are far more powerful and unpredictable than anything he's encountered before. And his relationships with his friends from Camp Half - Blood would also be put to the test as he becomes something more than just a demigod.
In the 'Percy is adopted by a Norse god' fanfiction, he could be given a new identity within the Norse world. This new identity might come with certain responsibilities. He may have to prove himself to the Norse community. And his friends from the Greek side might have different reactions. Some could be jealous, while others might be curious about his new life. There could also be a plot where Percy has to use his combined Greek and Norse knowledge to save both worlds from a common threat.
In this fanfiction, Percy could also become a sort of bridge between different worlds. His human experiences combined with his new family in the realm of Nyx and Erebus could allow him to bring about changes. He might be able to use his knowledge of both worlds to resolve conflicts or create new alliances. For instance, he could help the Olympians understand the primordial forces better, or vice versa.