Death.
The final rest; the phenomenon that occurred when the flames of one's life were snuffed out eternally. It was the extinguishing of one's life, or the moments leading up to it, that called upon the Shigami, the God of Death. The translucent, gaunt spectre with a demonic visage which wears a white burial kimono presided over the realms of life and death. Through life is death born, and through death can one pull life. It was an eternal cycle that fueled the shadow of Kami, a cycle that gave the Shinigami its true power. In its mouth of jagged teeth it carried an ethereal tantō, specially crafted to sever the soul from the flesh. In its right arm it carries prayer beads, purifying the freshly claimed soul for its journey through eternity; either everlasting peace in the Pure World, or wandering while suffering in Yomi.
There was only one known jutsu, created by the great Uzumaki clan of Uzushiogakure, that could allow one to forcefully conjure the great God of Death. This jutsu and its sole variant, however, required the user's life as recompense for willing a God to do one's bidding, to kill one's enemies. Of course, the Shinigami would perform this task with an ominous smile. Why would it not? Death and the souls of both the blessed and the damned fueled its power. The Dead Demon Consuming Seal not only allowed the Shinigami to claim the souls of the desperate shinobi's enemies, but to also claim the life of the desperate shinobi that thought to control the power of the Death God.
This, however, this was no jutsu and Naruto Uzumaki was no shinobi. He was desperate; oh yes, he was desperate. His blood continued to grow hotter in his veins as his body grew colder, yet he stood ever defiant in front of the traitorous, white haired chunin that was grinning madly. Behind the blonde boy with outstretched hands sit the chunin Iruka Umino, one of the four people that cared about the village pariah. The scarred man stared up at his most precious student, in both fear and shock. Shock because he could swear he was shielding Naruto from the fuma shuriken Mizuki sadistically aimed at him. Fear for the boy that he was supposed to shield, was shielding him instead. The fuma shuriken was a weapon that was literally the same size of the blonde boy whose chest it was deeply embedded in.
Mizuki hadn't conjured the Shinigami, for he didn't know of the Dead Demon Consuming Seal. Iruka didn't summon the Death God, and nor did the little Uzumaki. But the flames of the blondes short life were fading rapidly. Still, he stood before Mizuki in the hope of protecting one of the four people that even remotely cared for him.
Naruto Uzumaki was desperate; oh yes, he was very desperate. He didn't want to die. He didn't want Iruka-sensei to die. He couldn't die yet. He had yet to accomplish his dream; he hadn't yet become Hokage! But it did not matter. When one's life came to an end, it was not up to them. They were in the custody of the Shinigami, and the whiskered blonde could see the demonic visage of the God floating before him. In its left hand rest its tantō and in its right lay the prayer beads. With a malicious smile on its gaunt face, it held its hands out to Naruto. His vision was failing him. His body was growing weaker with each passing microsecond. He couldn't stop sweating and he was shaking violently.
The Shinigami looked at him as though to say, 'It isn't your time.'
The god waited patiently for the blonde to make his choice; tantō or beads. If he passed without choosing either, then the embodiment of death would claim his soul; time or not. Naruto didn't want to die, but he was getting so sleepy. As Mizuki continued cackling madly, as Iruka held the boy in his arms while he cried, as the flames breathed the last of their embers, Naruto reached out greedily with both hands.
As he made a choice that even the Shinigami had not seen coming, his heart stopped. All became still. Mizuki was pinned to the floor, restrained by two shinobi; a now emotion purple haired Anbu, and a white haired Anbu that had never tasted rage as he had just now. Kneeling beside the body of the still blonde was the Sandaime Hokage, the man who loved Naruto as though he were his own child. His wise, dark eyes held a hatred and pain so potent, it was a miracle that the Shinigami didn't at least receive one soul for his own thrice bedamned generosity.
The boy made his choice, though he knew it had been too late. With a wicked grin, the Death God reached to pluck the tender soul from the young boy from its cold vessel. Something happened to give him pause, however. Two beads from the collection of his necklace snapped off and sank into his lifeless eyes. The tantō extended, lengthening as it thinned to a near ridiculous point. The short katana of the Shinigami had become a sword revered in Kirigakure, ripped from the hands of its current owner. The wicked grin of the Death God turned utterly malicious; looks like it would get the two souls after all.
'Naruto,' he could hear his name called from somewhere in the hazy and ever changing landscape wherein he was trapped; the voice itself coming as an evil, rasping whisper. 'Do you want to die?'
He shook his head, his throat too sore to speak for some reason. 'I don't wanna die. I don't wanna die.'
'Then bring it to me.' the rasping whisper commanded. 'Bring me the eternally damned soul of your murderer. If you do not, I will reclaim my gifts and you will die alone.'
The blonde nodded. He would not ignore the voice of the god before him, for he did not want to die. He couldn't. Not yet.
His heart gave a single, violent thump as the Sandaime picked him up. Light returned to Naruto's eyes as chakra exploded from him; powerful as a waterfall, colder than death, and more sinister than any Jashinist. The God of Shinobi looked to boy as the chakra lifted him from the older man's, changing him. His blonde hair bled red, turning the very same black accented vermillion as was his chakra. His eyes, a pair of whirlpools that were deepest cerulean began changing, albeit in another way. His right eye changed from such an alluring cerulean to an almost sensual shade of violet as was his mothers. After the color was changed, both eyes turned a dull purple as concentric ripples emanated from his now shrunken pupil.
He was set on his feet as the chakra still caressed his flesh like a lover, a flame that was continually licking at the one thing it couldn't burn. Wobbling on his own two legs as though he had yet to grasp the concept of walking, he launched himself at Mizuki as the white haired man shouted for someone, anyone to restrain the demon. Naruto's hand splayed over Mizuki's stomach and he could feel the pulsating of chakra that rested in the man's core. He gripped that feeling and violent ripped his hand away from his murderer. All shinobi that were watching, stared in fear at the little blonde as he clutched blue silhouette of Mizuki.
As the man took his last breath, he stared into the depths of Naruto's eyes, taking no solace in the fact that the now red haired demon brat was the last thing he would ever see.
Somewhere in the back of Naruto's mind was the preternatural knowledge of this strange ability that his subconscious decided to name 'Human Path'; that instead of gifting this soul to the Shinigami as per their deal, he could instead absorb it and gain the knowledge the soul possessed. But as the strength he'd just received from somewhere in his core began to fade and he saw the Shinigami smiling viciously down at him, he held his hand out toward the Death God. The gaunt spectre took the entrapped soul and ate it with victorious relish.
'Excellent, Uzumaki Naruto.' said that evil, rasping that belonged to the Shinigami. 'Your soul is permitted to return to your body. I expect great things from you.'
As he lost consciousness, the Sandaime was there to immediately catch him. The leader of Konohagakure looked around at the three shinobi that were with him. This was no doubt an S-rank secret that could not afford to get out, and as Iruka picked up the strange, needle-like sword, none of the witnesses could shake the feeling that Naruto was going to change after this.