Well, it could be about Ash having daily adventures with legendary Pokemon. Maybe he stumbles upon a Mew in a forest and they start a friendship. He could learn about the unique powers and personalities of legendaries like Lugia and Ho - Oh in his everyday encounters.
Obviously, Ash would be one of the main characters. His Pikachu would also play an important role as his trusty sidekick. And then, there could be various legendary Pokemon like Celebi, who might befriend Ash and guide him through different adventures in the Pokemon world.
One idea could be a fanfic where the legendary Pokemon have human-like lives in a secret society. They deal with normal problems like friendship, rivalry, and finding their place in the world, all while hiding their true identities from humans.
By giving the Legendary Pokemon unique personalities. Instead of just being powerful creatures, make them have quirks, likes, and dislikes. For example, make Mewtwo be a bit of a loner who secretly wishes for friendship.
Maybe a story where Ash is transported to a realm where human legendaries live. He has to navigate their complex society and politics. The human legendaries might be divided into different factions, some believing in isolation from the normal Pokémon world, while others think they should be more involved. Ash could become a mediator, trying to bring peace between these factions while also learning about the unique powers and histories of these human - like legendaries.
There's a fanfiction called 'Ash and the Legendary Allies'. In it, Ash accidentally stumbles upon a secret place where legendaries live. He befriends them, starting with Articuno. As the story progresses, he teams up with different legendaries to save the Pokemon world from a new and powerful threat. It's really exciting as it combines Ash's usual tenacity with the extraordinary powers of the legendaries.
One popular one could be 'Ash's Legendary Encounters'. In this fanfiction, Ash has some really unique ways of capturing legendaries. He uses his bond with Pikachu and his friends in ways that are different from the main series. For example, when facing Mewtwo, he doesn't rely on brute force but rather on understanding and mutual respect.
In these fanfictions, Ash might develop a deeper understanding of power. Human legendaries are often extremely powerful. By interacting with them, Ash could learn about the proper use of power. He may start to realize that power isn't just about winning battles but also about protecting and nurturing. For example, if he teams up with a human - like Rayquaza, he'll see how Rayquaza uses its power to maintain balance in the atmosphere. This could inspire Ash to be more responsible with his own growing power as a Pokémon trainer.
Arceus is often a popular choice. It's the creator Pokemon, so there are a lot of possibilities for stories involving its power and the origin of the Pokemon world. Writers can explore how Arceus interacts with other legendaries and how it maintains the balance of the universe.