The Plate of Diamond (ca. 2800 BC)
Dialga was born to a herd of sauropods roaming the savannas of southern Africa, circa 2800 BC. He was not, however, a god from the beginning. He was born a mortal, just as any other pokemon, and belonged to an ancient species now extinct. This species was the ancestor of modern saurians, and closely resembled more recently-extinct species such as bastiodon and aurorus.
He, and all individuals of his species, possessed a strong affinity for steel. His body was clad in steel armor, and he could manipulate the metal as a weapon in physical combat. For many decades of life, he sharpened his skills and became a leader among his species.
High upon the peaks of the Drakensberg Mountains, in an area now called the Iron Crown Mountain, lay a brilliantly shining plate of interlocking steel and diamond. The metal and crystal held a strange, complex power within the networking structure, all hidden under another thick layer of steel that encased the entirety of a plate as an impenetrable shield. Most creatures dismissed it as unimportant, not realizing what power lay inside, and thus it went undiscovered for many millennia.
Dialga happened upon it on one occasion, in his travels to explore more of the land. He usually did not climb such towering peaks, but thought it useful to gain an aerial view of the surrounding country, so that he could survey his land and plan a route by which to lead his herd.
At first, when the sunlight reflected off of the brilliant plate of steel, he hardly noticed it. But then, as he turned back to climb down the peak, the light caught his eye again and he studied it more closely. It seemed unusual that the metal would be so perfectly smooth and flat, sitting untouched on the top of a peak. Curiously, he prodded it.
A sting of energy bit at his paw, but nothing happened otherwise. His curiosity flared, and he investigated it further. What could be inside the metal? Summoning energy within himself, he forced the steel casing open and reached inside.
Immediately, the godly power within the crystalline structure streamed into him and shocked his body. He was paralyzed completely, from crown to tail, as the transformation flooded his body.
His body was enlarged, his mind expanded. The metal armor that already adorned him lengthened and hardened, becoming unbreakable sheets of steel over his chest, head and feet. The diamond crystallized his bloodstream, slowing his heart rate considerably so that it pounded with an eternally steady rhythm - in time with time itself. Dialga did not know it yet, but he now held time's beat within his heart, and would soon learn to manipulate the dimension himself.
This transformation took many years, locking him in a sleeping coma, and his family all assumed him dead. When he emerged, they were nowhere to be found, and he found himself alone - and new.
Indeed, Dialga knew not precisely what had happened, but he knew this much: he had been reborn.