Many centuries ago, pokemon trainers had discovered a way to strengthen their pokemon to heights only now being matched. By a process likened by some to evolution and others to massive experience, a few species of pokemon went through a metamorphosis which dramatically improved their size, power, and attacks without changing their name or form, a metamorphosis called "Level X" because their power exceeded the existing leveling scale. Before long, their trainers challenged the great, feuding nobles of the realm, who were forced to master these strengthened pokemon themselves or lose everything.
Wars of upheaval swept the land and even the gods themselves sought this power lest they become outclassed by mortals. A pokemon professor experimented on many pokemon, hoping to bring peace to the land: instead, he found Flygon, the ultimate weapon of its time. The new Flygon had learned an extreme attack which slew other pokemon level X in a single blow, and would not rest until their targets were obliterated.
From the deserts, armed with Flygon level X, a generation of conquerors emerged. Yet no sooner did they establish their rule than did they turn upon one another like they had the giants they had conquered. The Flygon were themselves level X, so they saw each other as enemies and gleefully battled one another. A war of fratricide replaced the old upheaval, differing only in the diversity of pokemon used, until only one Flygon remained. Its trainer reached for the imperial crown, then looked up to see its Flygon still attacking. With no other pokemon level X left alive, there was only one more pokemon to kill, so it slew itself with its own technique.
Yet man continued to wage war with the pokemon who remained, species their forefathers thought too weak to send into battle.