Wars are fought over many things - there are wars fought over beauty, over power, over anything that humans might covet. At their core, humans are selfish, destructive beings that will do anything for things that they want. They share this bestial nature with other beings, but no people will wage wars over something as cruel as they are if they do not have something they desire - such is how the world has prevented itself from being torn asunder. Just as wars are fought over what humans want, wars are also fought over what they do not want - when a group of humans get too powerful, or perhaps when their views contradict a sacred doctrine, or a general consensus of morality. For each war, there is a victor, but who we know as the victor varies, for they say that all history is written by the victors, and one cannot paint oneself in the history books without gazing through a rose-tinted lens.
Through the lens of history, speckled and tinted with pink, massacres become triumphs against an enemy, dehumanised to the point killing them was not only justified, but a necessity - an act of glory, instead of the most profane debasement of human life. Through this lens we see wars as glorious, and necessary for the survival of a greater race, but we do not see the atrocities that were committed. We do not see these things because the truth is a single ray of light, pure and unadulterated, but it is twisted and unraveled and coloured through the eyes of the victors. The truth is not what we remember, and only those who fought during the wars can truly say if something is justified, or if the lens of human bias have distorted the truth into a mere shade of its former self.
Not all wars are like this. Some are so horrific, and so destructive, that while they rage on no lens can twist the truth away from its course, for the truth is dark and full of terrors. Such a war took place between the villages of our world. As all men covet power, when a power so immense that it promises dominion over all others emerges, it is wanted not by just the most powerful, but by those who feign loyalty, by those who have no power of their own and have been downtrodden by their capricious masters, and when the Nine Bijuu were released unto our world, a river of innocent blood followed them.
Villages split apart to better attempt control over the beasts, and turned on their brethren as they turned upon their enemies. As each man coveted this power so highly, none could trust another, and atrocities were committed. Atrocities that should never have been allowed were welcomed in the streets, as each man dead meant one man less to share the coveted Bijuu with. When society turns upon its lowest members, it never expects them to turn back. The poor and downtrodden banded together, training themselves in the arts of the superiors that they, too, might learn of power. They knew not what they coveted, but they desired it with all their hearts nonetheless, a fact that only made the awful wars sadder. Within but three years, some clans were on the brink of extinction, and even some villages hung on the delicate precipice between life and death. And still men fought over a power they could never tame, a power they knew they could never control.
The world was scarred by this conflict. Great rifts in the earth were opened up, rifts created by the strife wrought by men obsessed by power - wounds in the very land, a sign that the conflict had gone on for too long. It was in these days of the war that men begun to pray. Most had had their faith trodden in the war's wake, after seeing once-friends butchered beneath them, after watching their homes and their children and their spouses killed in the name of power they would never taste. They pantomimed the acts of war in the hope others could be convinced to continue, that the war would be over, but nothing short of a miracle could save them.
Just as great power and great beauty can inspire greed, they too can inspire salvation, and it was not long before the Bijuu were prayed to by the masses for an end to the blight that had ravaged the world. They prayed for life, for peace, and for an end to those who ruled over power. We cannot say if the Bijuu could ever hear the prayers of the masses, but History claims that they could - and that they struck down the corrupt men who had started the blasphemous wars in an act of mercy. It is closer to the truth that the Bijuu simply went on a rampage, and in their wake the corrupt were slain as readily as the chaste and virtuous.
Following this slaughter, at least a third of the entire world had perished beneath the weight of war. Those who remained universally agreed that such wars should never happen again, and that any object of power able to inspire such greed should be sealed away, kept from the eyes of men who would gaze upon it and want it for themselves. "The Great Mercy", they called it, as the men and women bound together to bring to heel the Bijuu that had caused so much devastation. In accordance with the religious doctrines invented around the Bijuu, they were sealed into vast shrines, and the shrines were distributed among the capitols of the world so that all might pay homage to the bound gods.
Konohagakure, hidden in the Leaves, was given the God of Nine Tails and the God of Four Tails.
Kumogakure, hidden in the Clouds, took the God of Eight Tails and the God of Five Tails.
Kirigakure, hidden in the Mist, claimed the God of Three Tails.
Sunagakure, hidden in the Sand, received the God of One Tail and the God of Six Tails.
Amegakure, hidden in the Rain, procured the God of Seven Tails.
And finally, Kyokujitsugakure, hidden in the Rising Sun, took the God of Two Tails.
Now, the villages live in prosperity, praying to what their long-dead ancestors tell them are gods in statue form. It is the merciful lens of History that has brought peace unto the world, and though History is normally written only by the victor, the forfeited lives of the dead wrote what we know today - that prayer to the gods is rewarded, and that peace reigns once more in the world. Without these bound gods, peace may not survive... But there are men who covet power.
Often, they start wars over it..