Perhaps there's a plot where Ash is chosen by some prophecy to capture Arceus. He then has to train extra hard and gain new powers or knowledge to be able to face Arceus. Along the way, he might make new friends or enemies who either help or hinder his quest to capture the powerful Pokémon.
Another plot could be that Arceus is in some sort of trouble and Ash is the only one who can save it by capturing it. This could involve a complex story where Ash has to figure out what's wrong with Arceus and how to use his skills to capture it in a way that helps it.
One possible plotline could be that Ash is raised by Arceus to be a sort of Pokémon messiah. He is taught the true essence of Pokémon and is sent on a quest to save the Pokémon world from an impending doom.
One possible plotline could be that Ash captures Suicune in an unexpected way, like during a special event in a new region. Then he has to deal with the consequences of having such a powerful and rare Pokémon, like other trainers being jealous or wanting to challenge him for it.
One possible plotline could be Ash gaining unique powers from Arceus. For example, he might be able to communicate with all Pokémon in a more profound way. Another could be that Ash has a special mission given by Arceus to save the Pokémon world from a great threat. And perhaps he has to face challenges that test his new - found relationship with Arceus and the powers it has bestowed upon him.
In some fanfictions, Arceus might be bound by some ancient rules that Ash unknowingly breaks. These rules are so important to Arceus that it feels compelled to betray Ash. For example, if there's a rule about not interfering with a certain type of Pokémon evolution and Ash does it accidentally, Arceus could see it as a major transgression and take action against him.
One interesting plotline could be Ash's discovery of his special connection to Arceus. Maybe he starts having strange dreams or powers that lead him to uncover the truth. It could also involve Ash facing challenges from those who oppose his new - found status as the 'child of Arceus', like some evil organizations that see him as a threat to their plans.
Well, you can try searching on fanfiction websites like FanFiction.net or Archive of Our Own. There might be a variety of stories related to 'ash captures arceus' there.
There might be some new characters introduced in the fanfiction. A mysterious Pokemon trainer who has some ancient knowledge about Arceus and can guide Ash. Or perhaps a group of Pokemon researchers who have been studying the relationship between Arceus and the world for a long time. These characters could add more depth to the story, providing different perspectives on the situation between Ash and Arceus, and helping Ash in his fight against the perceived betrayal.
In a fanfic where Ash betrays and captures Arceus, it could be a very dark and unexpected turn. Maybe Ash has been influenced by some powerful and malevolent force. This would completely change his character archetype from the heroic trainer we know. It could lead to a lot of chaos in the Pokémon world as Arceus is like a god in that universe.
In 'ash raised by arceus fanfiction', one could expect a lot of creative elements. For example, Arceus being a god - like Pokémon might raise Ash in a way that completely changes his understanding of the Pokémon world. It could involve Ash learning secrets about Pokémon that no one else knows, and this might lead to new adventures and challenges for him.
I'm not sure exactly how many fanfictions exist where Ash is the son of Arceus, but it's a very interesting concept. It could lead to all kinds of plot twists. For example, Ash might have some hidden powers or a special connection to the Pokémon world that others don't. This kind of fanfiction can explore the relationship between Ash and Arceus in ways that the original series doesn't.