One special ability Ash could have is the power to summon legendary Pokemon more easily. Given his relation to Arceus, other legendaries might be more inclined to answer his call. He could also have enhanced physical and mental strength. This would allow him to endure tougher battles and make quicker decisions. Additionally, he might be able to sense the emotions and needs of Pokemon from a great distance, which would help him in his quest to be a Pokemon master.
Ash could potentially have the power to control the elements related to Pokemon types. For example, if he encounters a fire - type Pokemon in trouble, he could use his ability to manipulate fire to help it. Also, he might be able to teleport between different regions of the Pokemon world, which would be a very handy ability for his adventures.
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.
Well, the plot could involve Ash getting transported to a special realm where Arceus resides. Maybe Arceus sees something special in Ash and decides to test him. Ash could be given tasks that are related to saving the Pokemon world from a great danger that only he, with the help of Arceus, can prevent.
A potential plot could be centered around Ash's role in a prophecy. Since he is the son of Arceus, he is the key to saving the Pokémon world from a great danger. He has to travel to different regions, gather powerful Pokémon, and learn ancient secrets about his father. His friends might initially be skeptical of his new identity but eventually come to support him as he faces numerous challenges and battles against powerful foes.
He could have a Froakie. It's a common and cute starter in Kalos. Maybe also a Skiddo for traveling across the Kalos landscapes. And a Bunnelby would be a nice addition for its digging abilities.
In such a fanfiction, Ash might gain some extraordinary powers. Since Arceus is a very powerful Pokemon, it could bestow upon Ash the ability to understand all Pokemon languages instantly. This would give him an edge in his Pokemon journey, allowing for deeper connections with his Pokemon and better strategies in battles.
One common theme could be power. Since Arceus is a very powerful Pokemon, Ash might inherit or discover new powers. Another theme could be destiny. His connection to Arceus might mean he has a special destiny to fulfill in the Pokemon world.
Team Rocket might be main characters as well. They could be constantly trying to capture Ash or his Pokemon because of his special status. Their bumbling attempts to take advantage of Ash's link to Arceus could add a lot of comical and action - filled moments to the fanfiction. And of course, Arceus itself could be a major character, guiding Ash in some way or interacting with him directly.
It changes the story in many ways. Ash would likely have some latent powers. Maybe he could communicate with Pokemon on a deeper level without the need for a lot of training. His battles could be different too. Opponents might be more hesitant to face him once they learn of his relation to Arceus. And in terms of the plot, it could introduce a whole new arc about Ash uncovering his true identity and what it means to be the son of Arceus.
Another theme is the power of friendship. Ash's relationship with his Pokemon is central. When he meets Arceus, his Pokemon friends might play a crucial role in the encounter. For example, Pikachu could use its electric attacks to protect Ash if there's any danger during the meeting.
One highly regarded story is 'Ash's Arceus Adventure'. In this fanfiction, Ash embarks on a journey with Arceus to stop an evil organization from stealing the essence of all the legendary Pokemon. The story is great because it combines action, mystery, and the unique bond between Ash and Arceus. Another good one is 'Arceus and Ash: The Legendary Bond'. It focuses on how Ash's pure heart and determination attract Arceus, and they work together to heal a sick Pokemon world. The detailed descriptions of the Pokemon and the emotions of the characters make it a top pick. And then there's 'Ash, Arceus, and the Time - Twisting Quest' where Ash travels through time with Arceus to prevent a cataclysmic event that would destroy the Pokemon timeline.