The Pre-Story.
In the beginning, there was the Wandering. Humans, the descendants of dragons and fairies, wandered across the world. They bunched together for survival and intermarried; families arose, and grew; those became clans, and clans united to form tribes. And some of the tribes begun to settle down along the great rivers of the world; the dragons there taught them to grow their own food, and granted them homes. Others, however, continued wandering, laughing at the river folk who so easily abandoned their old ways.
But there were more and more humans, and less and less food and space for them to wander in; so the tribes begun clashing more and more often, and in their fury raised their clubs and spears. Battles raged, and those who were defeated either became slaves or died - or fled into the distant corners of the world, where they were left alone, to die - for none can survive on pride alone.
And into the swamps and mountains fled the once-proud, now-broken Tai folk ("Tai" meant "Free People" in their language). Their situation was complicated, for they were running out of food and were surrounded by hostile tribes. To remain where they were meant to die and to cease being people, as corpses are merely former people. To come out meant to become slaves, and so cease being free, as slaves are merely former freemen. Arguments between the supporters of two courses became ever more heated - while the last food was consumed and the last escape routes disappeared.
At this point of greatest desperation, a sudden new leader arose - a young warrior was trying to catch some prey in the swamp, and saw a golden bird. Having heard of such birds in the legends, he begged for it to help him and his people. And so it did - for a price...
Long story cut short, the warrior returned with a powerful and well-decorated spear, and a new kind of confidence and charisma. His people stopped quarreling and listened to his speech without interrupting. Before long they accepted his plan, in spite of both their pride and the madness they would have called it earlier. With both courage and disciplinne, they emerged from the swamp and attacked their enemies. Taken by surprise - both by the attack itself and by the ferocity of the attackers - the enemy warriors were completely slaughtered and torn apart. The women, the children and the elders were rounded up, the camp was taken and the food supply seized; but they ignored it until the evening. Thus the golden bird has kept its side of the agreement; it gave the tribe what it needed to survive.
And the warrior - and the tribe - repaid it as per the agreement. They sacrificed all the captured enemies, and made a pact with the Golden Bird, like the river-folk made a pact with the dragons. They pledged to worship it, and to bring it annual sacrifice in human blood; and to conquer all that they could in its name. And just as they became the chosen people and the instrument of the Golden Bird in the human world, so the young warrior - and after his death, his lineage - became the instrument of the Golden Bird within the tribe, a divinely-chosen leader who shall lead his tribe in its divine campaigns of conquest. And the chosen people then took on a new name - the Rajai, King-People, who were to rule the world for the Golden Bird. And the young warrior took on a new title, which also became his name; he became Rajaraja, King of Kings: in history he shall be known as Rajaraja I.
After a few more months, the Golden Bird appeared again and gave Rajaraja I the second of its many divine orders for the Rajai; he was to lead the Rajai south, to more fertile lands, where the first true campaign of conquest was to begin. And so he did.