One interesting aspect could be the unique battles. In fanfiction, Ash might face legendary Pokemon in ways that are different from the main series. For example, he could have a more strategic battle against a Mewtwo, using his Pikachu in a completely new way.
One possible plotline could be Ash's discovery of his own latent legendary powers. Maybe he starts to exhibit abilities that are unique to legendary Pokemon, like controlling the weather or having an extraordinary bond with all types of Pokemon.
In some 'legendary pokemon and ash fanfiction', there might be a plotline where Ash travels to a hidden realm where only legendary pokemon exist. Here, he has to prove himself worthy to the legendary pokemon in order to gain their help in his journey to become a pokemon master. This could involve facing various trials and challenges that test his skills, courage, and friendship with his pokemon.
Well, one interesting aspect is the way it can play with the over - the - top powers of legendary Pokemon. For example, making Articuno use its ice powers to create ice sculptures of other Pokemon in really goofy poses. Another aspect is the character interactions. Imagine Mewtwo trying to understand the simple - minded humor of a Pikachu in a fanfiction. It can also be interesting how the fanfiction might use the mysterious nature of legendary Pokemon to create comical misunderstandings, like Dialga accidentally messing up time and causing all the Pokemon to have their voices switched.
One possible plotline could be that Ash has to overcome his own self - doubt. He might initially think he's not worthy of catching a legendary pokemon. But through his journey, he discovers his hidden strengths and forms a deep bond with the legendary pokemon. For example, he could learn that his pure heart and unwavering determination are what attract the legendary pokemon to him.
One interesting plot could be Ash forming an unbreakable bond with a Legendary Pokemon. Maybe he helps the Legendary in a time of crisis, like saving it from an evil organization. This would lead to the Legendary choosing to stay by Ash's side and help him in his battles and adventures.
One interesting storyline could be Ash getting a legendary starter that has a unique bond with him. For example, it might be able to communicate telepathically with Ash. This could lead to them having a deeper understanding of each other and facing challenges in a new way.
One of the Legendary Pokemon could be Giratina. Despite its somewhat dark and otherworldly nature, Giratina might be intrigued by Ash's light - heartedness and his ability to make friends with all kinds of Pokemon. Dialga and Palkia could also be part of the harem. Dialga, with its control over time, might see Ash as an important factor in the future of the Pokemon world. Palkia, in charge of space, could be interested in how Ash navigates different regions and spaces in his journey. And don't forget about Ho - Oh. Ho - Oh is a symbol of hope and might see Ash as a bringer of hope in the Pokemon world, thus joining his harem.
One possible plot could be Ash being chosen by Arceus to save the world from a new, mysterious threat that even the Legendary Pokemon are powerless against. He has to travel to different regions and form bonds with various Legendary Pokemon along the way, using their combined powers to face the danger.
The appeal lies in seeing Ash in new and exciting situations. With legendaries involved, his journey becomes more epic. It's like taking the underdog story of Ash in the anime and supercharging it.
In Ash-centered legendary Pokemon fanfiction, often Ash has extraordinary adventures. He might form unique bonds with legendary Pokemon that are not seen in the official storylines. For example, he could befriend a Mewtwo and together they face off against an evil organization trying to clone more powerful Pokemon. These fanfictions allow for a lot of creativity, expanding on Ash's character and his relationships in the Pokemon world.