Gold & Silver Brothers
Kinkaku and Ginkaku are the Gold and Silver Brothers, the greatest heroes and villains in the history of Kumogakure.
Truthfully, they are half-brothers born from two different mothers within a year of one another. Kinkaku was named for his mother's golden blonde hair while Ginkaku was named for the silver of his mother. Their father was a man of great vice descended from the Sage of Six Paths and both of his sons were inherited the strength of that ancestry. He trained them in the ways of shinobi until they were old enough to fend for themselves where they left to work as a two-man team.
Even when young, they possessed remarkable talent and power that allowed them to fight against enemies older and more experienced than themselves to succeed in their missions. More than often, they deliberately sought challenges were the odds were against them and still managed to come out on top.
One such challenge was to collect the Treasured Tools of the Sage of Six Paths that had been scattered around the world. They read the stories, sought the rumors and tracked down every single one regardless of how well protected they were or who wielded them. Then, to protect these tools from others, they sealed them within their bodies in such a way that only they would be able to summon them.
Thus it did not take long for them to became known as the Gold and Silver Brothers.
When Kumogakure was founded, the brothers had audacity to invite themselves into the organization. It was an unusual situation as only established ninja clans were joining the hidden villages at the beginning due to their strength and numbers. But their legendary reputation, proven skill and possession of the Treasured Tools were enough of the deal breaker that they were made welcome.
Within the hidden village's first year, they decided that their next greater challenge would be to fight and capture the Nine-Tailed Demon Fox with the Treasured Tools for Kumo. And they did find and fight the Tailed Beast but underestimated its power. Instead of capturing it, they were eaten alive and found themselves trapped within a belly of the beast.
None of their jutsu could overcome its immense, malignant energy and not even the Treasured Tools were of any use from inside it but they continued to fight for their survival. in the meanwhile, the brothers ate the fox's flesh and drink its blood to save themselves from dying of malnutrition or dehydration. Anyone else would have sickened and died from trying it but their heritage gave them a unique resistance, not only surviving but thriving on it.
By eating the chakra-made flesh, Kinkaku and Ginkaku assimilated that chakra into their own body. It altered them to mark their faces with whiskers, increased the quality and quantity of their chakra and, most importantly, granted them a permanent well of the Nine-Tails' chakra.
At any time, these pseudo-jinchuuriki could wrap themselves in a cloak of blood and chakra that turns them into a miniature version of the beast. They only possess six tails' worth of its chakra but are capable of incredible destruction, protected from many types of damage and retain their consciousness without the will of a Tailed Beast dominating their own.
When they returned to Kumo, having their failed mission but stronger than ever, this power was kept secret among the higher-ups. Whenever they used it on the battlefield they ensured that they killed everyone involved to prevent rumors of their ability from spreading. And the ones that did spread were simply considered exaggerated tales of their abilities.
Kinkaku and Ginkaku came to be known as Kumo's twin rays of light during the First Shinobi World War as they fought on the front lines to great effect. They even developed a following within their own hidden village as a number of ninja wished to train under their guidance and fight by their side. Each brother was formed a force of their own ninja - the Kinkaku Force and Ginkaku Force respectively - who went from battlefield to battlefield to wage war against Kumo's enemies.
But when Konoha and Kumo entered talks to form an alliance that could end the war, the brothers were against it. They had no interest in siding with their enemies and believed that they should destroy anyone who stood against them rather than seek peace through concession. In light of this, Kinkaku and Ginkaku attempted to launch a coup d'etat by killing the Second Hokage and Second Raikage during a diplomatic meeting.
The Kinkaku and Ginkaku Forces assaulted the meeting, killed the guards and were even able to murder the Second Raikage. However the Second Hokage was able to kill Ginkaku before escaping the ambush alive.
Enraged, Kinkaku swore vengeance against the Hokage for the death of his brother. Having failed their mission, he was forced to abandon Kumo knowing that he would be branded as a traitor for his actions. especially since the Treasured Tools sealed by Ginkaku were inaccessible even to his brothers, making the Amber Purifying Pot left in Kumo's possession as it was used to hold their tailed Beasts.
What was left of the brothers' followers unified under the name of the Kinkaku Force and went with him into exile. They continued to participate in the war for their own ends and killed everyone who was sent after them.
During the closing stages of the war later that year, the Kinkaku Force was able to confront the Second Hokage once more. Sacrificing himself to protect his team, Senju Tobirama battled them all single-handedly in a final battle that led to the death of everyone involved, including Kinkaku.
The Gold and Silver Brothers would be remembered as the greatest heroes who fell from grace to become the most reviled criminals in Kumo's history.