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.
Well, if Ash betrays and captures Arceus in a fanfic, it might be because he has some extreme goal in mind. He could be trying to reshape the Pokémon world according to his own vision. However, this goes against his usually kind - hearted nature. It would be interesting to see how other characters like Pikachu would react to such a huge change in Ash.
Perhaps Ash has been deceived by a false prophecy or a mysterious figure. This false information could lead him to believe that capturing Arceus is the only way to save the Pokémon world from an impending doom. So, in his misguided attempt, he betrays Arceus.
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.
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 '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.
Well, it could be that Ash makes a discovery that goes against Arceus' grand plan and is thus betrayed. Maybe he finds out something about the balance of the Pokemon world that Arceus doesn't want known.
Well, often in such a 'ash gets betrayed fanfiction', the story might start with a seemingly normal day for Ash. Then, out of the blue, someone he trusts deeply, like Pikachu or one of his human friends, does something that he perceives as a betrayal. This could be something as simple as not believing in him during a crucial battle or siding with an enemy for a reason that's not clear to Ash at first. It can create a lot of emotional turmoil for Ash and make for a very engaging read.
One possibility could be that in the fanfiction, Ash betrays Latias out of a misunderstanding. Maybe he was tricked by a villain into believing that Latias was a threat to the region. This would create a lot of drama and conflict in the story as Latias, who probably trusted Ash, would be deeply hurt.
In fanfiction, a story about Ash and Latias being betrayed could be really heart - wrenching. Maybe it could involve Ash being wrongly accused by his friends and Latias being forced to turn against him due to some dark magic or false information. It might explore themes of trust and friendship being broken.
Ash would likely be extremely heartbroken. He has always had a deep connection with Pokemon and believing that Arceus, a powerful and supposedly benevolent being, has betrayed him would be a huge blow. He might become withdrawn at first, not knowing who to trust anymore.