Author's Note: An idea for this fic just struck me one day, as I was ruminating on the various legendary Pokemon and their connections to each other. I started to think of stories and legends involving them, and for some reason they took a weird, comical bent. I couldn't resist putting pen to paper after that.
Arceus
Type: Whatever it wants to be
Species: The Alpha Pokémon
Home: Hall of Origin
Arceus is the ultimate creator of the Pokémon universe. Conceived in a void of utter nothingness, its emergence into existance brought with it reality itself. After its conception, Arceus created a number of beings that brought the new universe into balance: Dialga, Palkia, Giratina, Mesprit, Azelf, Uxie, Kyurem, and Victini.
Eventually, he became bored of drifting endlessly in outerspace, so he created Earth. Groudon, Kyogre, and Rayquaza were brought into being to help shape and maintain this new rock, and he fashioned a home for himself on a mountain in what would become known in the future as Sinnoh. To populate the planet, he created a prototype Pokémon called Mew, and set it free to evolve and prosper. Life was good...for a time.
There were little conflicts, to be sure. Giratina attempted a mutiny when Arceus told its initial batch of beings that they would have little to no say about the governing of the new world. Giratina was easily banished to the Distortion World, and things soon returned to normal. However, the betrayal by one of its own creations started to make Arceus anxious about the powers it gifted to these autonomous beings.
To complicate things, a new Pokémon was discovered one day when Kyogre was helping Groudon form a particularly tricky cliffside-waterfall combination. Arceus came for closer investigation when Kyogre reported that something was moving boulders to block the flow of water down the cliffside. To its surprise, Arceus found a large, golem-like creature moving and adjusting rocks, constructing what seemed to be a sculpture of itself.
Arceus had no knowledge of creating such a creature and could not imagine a Mew producing such a thing. Fearful that there might be another Pokémon ab aeterno, it attempted to smite the being with Judgement. However, to his great shock, the behemoth not only resisted the attack, but countered, thrusting its arm out and grabbing Arceus with suprising speed. Arceus cried out for help, and Palkia immediately arrived and warped him free.
The golem, now known as Regigigas, later proved to be an invaluable asset to Groudon and Kyogre once they learned how to communicate with it. However, Arceus would never forgot its first brush with danger. The idea that there could be a being with enough power to threaten itself haunted it from that day onward. Soon, Arceus stopped venturing around the earth, relying on news updates brought to it by its progenies to its home on Mt. Coronet.
As human and Pokémon civilisation progressed, people eventually forgot about Arceus. It was relegated to obscure myths and legends, and only its inner circle of Dialga, Palkia, and Uxie had any sort of regular contact with it.
When Arceus pondered its marginalization in history, it came to the conclusion that its lack of presence may cause some of the other legendary Pokémon to doubt its power or authority. To remedy this, it made an extremely ill-advised trip to the Johto region to compete in the Pokéathlon. It teamed with celebrity trainer Chad "Totally Radical" Conway to compete and show off its power.
It lost to a Sunkern named Mr. Ploofsie.
After that crippling embarrassment, Arceus assumed that even the most pitiful-seeming Pokémon posed a monumental threat to itself. It broke off the corporeal connection to its home in the Hall of Origin, and sealed the key- -the Azure Flute- -inside so that the only way into the Hall was for Arceus itself to open it up. It has rested inside ever since, its only direct link to Earth being through the mind of Uxie, who provides Arceus with occasional updates and bits of knowledge on the world. Arceus constantly orders Uxie to collect information on what it thinks could be possible traitors or saboteurs. Uxie humors it, as do the other legendary Pokémon, but no one takes it seriously anymore.