Gilbert was not quite sure what had happened. One moment, he was digging through his video game collection and found a strange pink cartridge that appeared to be a bootleg Pokemon game. The next, he was blacking out and waking up in... a forest.
He blinked as a few Pidgey flew over head, then looked around and noticed Metapod hanging from some branches while a Beautifly fluttered by.
Staring at the real life Pokemon before him, Gil decided on one fact that was clearly evident about his situation.
"I'm definitely dreaming. Maybe in a coma," he commented out loud, only to freeze as an unfamiliar voice chuckled nearby.
Oh, I assure you that you're not, my dear mortal! Glancing around at the strange voice that seemed to be talking both out loud and in his head simultaneously, his eyes fell upon an Umbreon lounging in a nearby tree branch. However, the dark Eeveelution seemed unusual: its pelt was the deepest black he'd ever seen, and its markings and eyes were a bright glowing green instead of the usual yellow.
The Umbreon leaped down from its perch; instead of landing, however, it seemed to melt on impact, splashing into a dark puddle that quickly rose up and took the form of a Zoroark that began to stalk around him. Once more, its pelt was dark as a starless night, and its eyes and the red coloration typical of its kind were both a glowing green.
This is all quite real! You've really been transported into the world of Pokemon! At least, one version of it, arranged by yours truly!
Gil was panicking at the bizarre entity that was stalking around him only for it to jump and distort into the shape of a black Serperior, circling him with its tail as it brought its face close to his. It smiled, its fangs glowing green as well.
"Wh-what are you? What do you want with me?" Gilbert stuttered, terrified.
Relax, Gilbert! I'm not going to hurt you! I just want to have some fun! it laughed teasingly. I'm called many things, but to make things simple you may call me The Creator. My purpose is to create and shape universes. And... well, on the side, I like to toy with universes that don't belong to me. This Pokemon world is one of my favorites! So much potential for chaos and mischief!
It pulled back from him, changing form to a pure black Gardevoir. It was then that Gil would recognize that the being's voice kept fluctuating from male to female, sometimes both at once. He could only listen as it monologued to him further. You see, a favored pass time of mine is pulling mortals like you from your world into worlds such as this one and seeing what you do when I... and a few others like me... tweak things a bit. Sometimes they are to your tastes... sometimes they're more our own, and you're just along for the ride. You're the first I've decided to reveal myself to, and that is for one specific reason.
It let that question hang in the air as it turned towards him, suddenly taking on the imposing form of Arceus itself, as always keeping its black and green color scheme. Gilbert, my precious little mortal... I am granting you godhood!
There was a pause as Gil took this in, staring the strange otherworldly entity in the eyes. "What?" he simply asked after a moment.
It's quite simple. I've seen what many of your kind have done when I and my contemporaries have toyed with you, altered your realities or granted your deepest desires. So now, I want to see what you will do with the sort of power I wield. You are in a completely normal, unaltered Pokemon reality. You will be the de facto god of this world, free to bend it to your every whim. Reality is your plaything, anything you desire shall be so. Am I making myself clear?
Gilbert pondered this, unsure what he would even do with such power. Still, it was a tempting experience, being able to shape his story however he wanted to... and it seemed like he didn't have a choice in the matter.
(Author's Note: I saw others introducing their own supernatural entities to this world, and figured I would throw my own personal one into the mix. This is, semi-canonically, the source of all the weirdness in every branch of the interactive. It is not required to reference this at all, I just thought it was fun.)