In myth, Arceus is often revered as the deity who created the universe and everything else in it with a thousand arms after having begot itself. If investigation is taken a step further, one will find that Arceus is said to have created the universe, then created three eggs which hatched at a murmured command.
Dialga, Lord of Time.
Palkia, Master of Space.
And finally, Giratina, Ruler of the Reverse World.
Having allocated the fledgling Gids their respective domains, Arceus then worked tirelessly to create the world as we know it, before populating it with inhabitants. Over the course of millennia, Pokémon, humans and other types of beings evolved into separate, distinctive species.
Less-known stories whisper of how Arceus seemed to favor Pokémon, often granting several species boons that made them into what they are today. Older tales from a bygone generation talk of Legendaries being such an example of fortuitous receivers of said boons - whether it is at birth or at a later point in life is debated. They are often dismissed by most of the community at large to be shrouded in superstition - however, some older, more traditionalist characters maintain this belief. However, there is one thing that almost everyone agrees on - that Arceus created everything near the dawn of time and has slumbered ever since.
Falling, falling, falling...
It had always been told not to fly over Cinnabar Island's Volcano, a hulk of a rocky turret with a gaping maw parted to reveal churning orange liquid that consumed all and, given enough time, left nothing behind.
But just as the punishment was steep, the rewards were great - jets of hot air propelled the Pokémon high up into the air and sped it along it's journey, cutting a flight short and saving many precious hours. However, more often than not, the ones who choose this path ran out of energy before they could fly clear of the volcano's mouth, and the same jets that guided and pushed did nothing to slow the spiraling descent of the unfortunates into the gaping crater that was the volcano. Now, young and old flying Pokémon alike eschewed the route, with only those who wishing to prove their might taking the plunge.
It wasn't like there was a choice anyways, the brown and tan avian mused. If they took the detour which brought them around the volcano and ensured their safety at the cost of extra time, their Sandshrew friend would have died by the time they got there.
And that was no choice at all.
By now, the Pidgey could feel their flesh bubble, feathers starting to bend and morph form the sheer heat. Despite all efforts, the berry it held had dropped and burnt to a crisp, another item lost to the volcano's ever-insatiable appetite. Letting out a pained screech, the unfortunate Flying Type's cries broke off with a gurgle.
When first contact with the magma was made, they noted that it felt surprisingly thick, like the remaining yolk from newly-hatched eggs.
Then, a moment later, the pain set in.
The Pidgey opened its mouth in a silent cry, ringing and yet remaining trapped under the cover of violently roiling magma that seared, burned, tore away feathers and flesh, sparing nothing for mercy. It felt like the pain of a lifetime condensed down into one frozen moment, before being loosed all at once.
Except... why did it feel comfortable, like soaking in a hot spring?
It snapped its beak shut, mind-numbing terror at the thought of eternity served cold replaced by confusion. The sensation spreading slowly along like flames advancing slowly and inexorably felt odd. Yet, it somehow felt natural, like finally having something go right after a long day of pitfalls and mishaps. It was akin to unwrapping a bandage and removing the poultice to expose the healing wound beneath; like shedding skin - except it wasn't only limited to skin, it reached down to the very core and burnt that away alongside the body and soul.
And right at that very moment, eyes that had once been squeezed shut in the face of death snapped open, just in time to witness the last of its wings being assimilated into the lava.
Messages exchanged between flocks of flying types occasionally included whispers of how unfortunate souls falling into the lava are merged with a fraction of what claimed them, being reborn as an entirely new being. And yet, in having gained arms and power over fire, they would be denied the joys of hearing the wind whistle as it caressed them tenderly, denied the chance to savor the taste of freedom that came with flight as they soared to new heights with their companions. Just as they were given new life, they were also tied to the earth, forever unable to reclaim what they lost.
Had there been another soul ensconced in the lava, they would hear a lone squawk of fear at the prospect of the change to come amongst the crescendo of cries accompanying their own suffering.
Tell me, child, why are you here?
A voice that sounded like thousands melding into one resonated through the bird's battered brain. The reply was chirped hoarsely to nobody, but even as they were left alone to consider their impending transformation, it knew in its heart that it had been heard.
Daring to sneak one last look at the burnt remains of their former freedom before they gave way to arms, it did just so, and let out a cry of shock.
Instead of the long, thick, and stocky, clawed arms it had been expecting, there were a pair of wings that grew rapidly by the second, until they became something far larger, stronger and more majestic than it could ever imagine, let alone be graced with.
Many who perished attempting to traverse the volcano before you only did so out of their own hubris, wishing to demonstrate strength that they did not possess, and thus I let them burn, the voice chorused. Some had fallen during the initial exploration of this route, having underestimated the distance, and so I kept their wings from being seared away by the lava, letting them live to tell the tale. However, this is the first time I have seen someone so willingly put themselves at such risk for a loved one. And for your valor, not only will your friend be healed, but I shall reward you with the ability to fly higher and longer than any of your brethren shall be capable of.
Had there been any witnesses, an elongated beak was the first thing that they would have seen emerging from the bubbling lava, followed by a golden blur cloaked in a blazing halo of orange-red fire. Surveying its new body, the reborn creature let out another caw. This time, it was one of delight.
Its feathers were now golden, tinted with a light orange that was reminiscent of the magma it had been soaked in. Like its beak, its legs had lengthened, long white claws growing out from its toes. Fire that it had once fallen prey to like every unfortunate victim before now burned brightly and powerfully along its wings, as well as forming a crest on its head. Although it lacked tail feathers, the flame that burnt in its place was undeniably, intimidatingly beautiful, just like what flared up in its eyes.
Rise, Moltres. Take to the skies. Fly.
Gratefully, the newly christened Moltres sent a loud screech skywards, before flying away and showering the land with tiny sparks of embers in its wake.