foreword: Kitsune are often said to have the power of infinite vision (omniscience) upon attaining their ninth tail. Naruto, meanwhile, developed the Sexy Jutsu as an anti-pervert technique.
Now, let's take those two lines of thought and bring it to a slightly darker conclusion. Naruto will still be heroic, but he will have vastly different methodology and mind-set than his canon counterpart.
Persistence of Vision
In hindsight, Senju Tsunade - the Godaime Hokage - should have seen it coming a mile away.
The first sign was when a very different Uzumaki Naruto returned from his training trip with Jiraiya, his skill set vastly improved.
None of the ninja who got to team up with him noticed anything amiss, except for the strange looks he sometimes threw at passing people in the streets.
This was around the time the first disappearances began.
At any rate, the first thing he did upon returning to Konoha was to march towards Konoha's General Hospital like he was the Hokage, rang for Sakura and Ino, and immediately showed them a few of the fruits of his three-year training trip - in the form of several paper tags.
"...I sealed up a bit of my 'other' chakra - you know, the one I use to regenerate quickly, if you're following the other Hidden Villages' Bingo Books - into this. Without getting into too many details, I tweaked your typical chakra-holding seal to account for its users control, modified the arrays to augment the control in response to application of outside chakra, and added a variable-release framework so it doesn't burn out quickly. Long story short, if you add medical chakra to this, you can heal even near-lethal wounds," he had told Sakura and Ino, handing them several of these "emergency healing" seals.
The two medic-nin thanked him, and almost at once, Naruto's expression went from pensive to peaceful, as if a burden was removed from his back.
...Almost as if his little gesture of kindness would end up saving a life in the future.
That night, two civilians disappeared.
No wonder he always felt... off, around that girl.
Upon his return, the weight of her thoughts, her obsession with him... back then, it would have inspired him.
But ever since that fateful day he and Jiraiya tried to use the "key", everything changed.
Now, her visions of him put undue pressure on his spirit, a burden he could never get the courage to ask her to ease on.
He glanced backwards to where he knew she was following him and sighed.
We can never be... and I don't want to break your heart. Maybe it's better that this is the minimum distance between us.
He smiled and walked away, knowing that sometimes doing the painful thing is correct.
Naruto-kun...
The host is... weak.
He cannot sustain this for much longer.
I may finally be... free, but this may be a price too high even for me to pay.
It does not seem just that he has to deal with this, all of this... alone.
He may be the one to change the world for the better... but with so many changes to see and do... why not just do nothing and see how the world unfolds, hmm?
It is what you call your nindo that ultimately dooms you to this wretched existence, little boy.
Konohagakure was once again saved - and it took the guts of one Uzumaki Naruto to pull it off.
He didn't even need to win the fight against the entity sealed within him; all both of them knew was that for every dead Akatsuki, the trail led closer to their leader, the one ultimately responsible for this mess, the man called Madara.
I'm not doing this out of the kindness of my heart - if I had one. Madara must be stopped at any cost.
I'm not asking you out of kindness. I've already seen what happened the night you got sealed in me. We'll deal with everything else later. What's important now is stopping the Uchiha scion.
By then, his dream of bringing Sasuke back was no longer a factor in his decision-making. Sasuke was a puppet, thinking he could live for himself, but in reality, he was dancing to the tune of a clan long since dead.
He could almost see the ghostly fingers of Fugaku, Mikoto, Itachi and countless other Uchiha wiggling their fingers as their little marionette put on a show for their entertainment. The departed - still running the show even after the end.
How sad.
Maybe that was why Sasuke's eyes finally became clear moments before Naruto shoved a Rasengan in his former teammate's gut.
You saw them.
You saw what was driving me.
You freed me.
Thank you...
This is not just my strength! This is the strength of others, the cries for help unheard, the deaths unavenged, the lost and the damned! This is their strength! Which is why you will not rule over me, Kyuubi!
My name is Kurama. Remember it, boy!
You hear them! Add your strength to mine, so that I may no longer hear their cries!
You will NEVER stop hearing them!
Still...
...please. Give me strength. Not your power.
I want you to say that what I am doing is right.
You... you would wish that for me?
I do not know any more. Seeing everything... I cannot shoulder this responsibility alone, Kurama.
The fox smirked.
Very well, I shall be your conscience, for having the power of one with nine tails essentially obliterates yours... Naruto!
Both fox and jailor clashed again in the depths of the jailor's mind...
He had made sure to scatter the dust that was Uchiha Madara's remains to the winds - after some serious talk with the Rinnegan wielder, he finally relented.
The man known as Pain finally succumbed to the constant use of his jutsu in a lonely cave with only the paper-user by his side.
...and Naruto.
He owed it to Nagato; after all, he had spared their sensei - even if all the ninja things he'd be left doing was that invisibility jutsu for doing "research".
But, still, at the close... he could not find the clarity that Sasuke, Madara, and Nagato found when the end finally came to them.
Confronted with the meaninglessness of what he wanted to achieve, Nagato had done what to the boy was impossible.
He lived out his last few days with meaning.
The woman who provided him comfort to the end took up leadership of Rain and brought the weeping land and its Hidden Village back to its former prominence.
But... while inspired by Nagato's example, Naruto didn't want any part of that.
He thought about Konoha and the meaning he would forever try to chase, but forever come up short...
...and decided to return home while thinking about the future.
After several long years, he had finally been discovered.
The recently-revived Police Force was aghast at the sight - the young man carried a bloody kunai in one hand and a severed head in the other.
He spared the gathered policemen a glance, as if committing bloody murder was little more than a walk in the park for him.
"Did you know that this man has ruined the lives of twenty-four people so far?" the young man began, lifting the severed head up a bit.
"His M.O. is as follows: he finds blackmail material for a target, pressures the target to betray her lover, seduces her in front of her lover and then discards her after he's used her up. Sad, really."
"Captain, you've got to see this! There's got to be like, thirty to forty others down here!" another officer said, the voice coming from the basement.
"That last one I dumped there... he's a civilian who took up injutsu training in his spare time. Makes girls cheat on their lovers via his sexual prowess. Who knows how many children are running around now that he's fathered. And what's worse, the husbands either don't know... or don't care."
"What happened to you?" the Police Captain said, the cigarette on his lips long-since burned out. You're not the friend I know.
Red, slitted eyes bored into black ones.
"Work... my work is never done. And that little boy of yours... Shikato?" the young man asked, sighing balefully. "He's not your son. This lunatic is the father. I'm sorry I didn't get to him sooner."
"What... does it matter?"
"Doesn't it hurt you? The betrayal?"
"You know that's not the point here, right now. How could you take on all of this yourself?"
"How could I not? When all around me, I see them. I see their thoughts. I see their dreams. I see the things people think they have locked deep within their heart of hearts."
"You'll have to turn yourself in. Amaterasu shining on high, this is really troublesome business."
"Fine. Allow me one last gesture before I do."
He flung the bloodied kunai out the window, the knife missing the officer's cheek by millimeters as it flew by.
A gash blossomed on his cheek as the telltale crackling of Wind chakra was heard outside... and then a crunch was heard, sending the people outside the house into a panic...
"Now... I surrender."
The red-eyed young man raised his hands in surrender, dropping the severed head, and walked towards his former classmate, unmindful that he had finally been found and caught.
"How did it come to this...?"
"It was always one of the outcomes in this situation, Hokage-sama... one of the possibilities."
"That doesn't mean you have the right to butcher civilians just because of your sense of 'justice', you know."
"Justice? Me? For most of my life, I've been treated with baleful glances, fearful stares and outright ignorance. The Academy teachers called me some sort of little monster - which I thought was figurative before because of my pranking days, but turned out to be literal - I didn't get the time of day from my team. To make matters worse, the only girl who actually liked me was this creepy stalker - only way I found that out was when I could not smell her scent around me after the Chunin Exam preliminaries; and I even thought that was a good thing up until now.
"But that's all right. Even the Uchiha defecting, putting a Chidori through my chest, that's all right. Being called a failure for not fulfilling my promise - that's all right. Remaining a genin for the rest of my ninja career - that's still all right to me."
"You know why, Hokage-sama? Because I am who Konoha wishes me to be. Even now, that hasn't changed."
"But upon my return, something did change. Konoha was no longer the place I wanted to protect. Konoha became a hive of monsters far worse than me. Your perverted former teammate-slash-author-of-cheap-porn-on-text? He's one of the tamer ones, comparatively. And I had Nagato make sure he'd pay for his role in continuing to create the monsters I hunt down."
"What makes you say that, Naruto?" the Hokage asked. "What happened back there with Jiraiya?"
Naruto chuckled darkly. "The key."
"Yes, I remember him saying something about how there was a key to your seal, to allow you to use more of its power..."
Naruto shrugged.
"I didn't gain any power, if that was what you were trying to get at," Naruto explained. "And while the Nine-Tailed Demon Fox is not a kitsune or a fox youkai... it still carries the image of one. When the key was turned..."
Senju Tsunade gasped.
"The key... it saw the image of the kitsune... molded you in its likeness... not the Demon Fox..."
"That's right," Naruto said. "And what happens to a kitsune or a fox youkai... when it gains nine tails?"
"Of all the kami, this can't be..." the Hokage said, her face turning deathly pale as her mind started working back to the time of Naruto's return. "...You gave my apprentices those paper seals, you knew what was going to happen, you could see them, you saw Asuma-kun..."
He gave a tired smile.
"The Nine-Tails calls it omniscience. I call it how the work of a hero never ends."
"You don't mean... every murder you committed... they were..."
"I see people's thoughts, Hokage-sama. I see their plans. I see their motivations. I see everything. Did you know that the first disappearance was of a genin? I saw what he was planning to with that friend of his. He was going to bring that girl from the Ninja Academy to the Training Ground no one frequents, bring his friends, gang up on her and slit her throat when it was all said and done... it was the first murder - deliberate, cold-blooded murder - I've done on a fellow Leaf genin."
"But... right after I saw what would happen... it was okay. Because what they planned to do to the girl was far worse than the fate they met in my hands."
"From there, killing just got a lot easier. The more repulsive ones were the ones I didn't scrimp on. You should have seen them when I read their thoughts and spoke them out loud."
"My God... that was why you nearly leveled Kumogakure..."
"With the Raikage's blessing, too, I might add," Naruto finished. "So... if you're going to punish me for my so-called crimes... go right ahead, Hokage-sama. I'm not going bother defending myself for all of this. All you need to know is that everyone I put down were monsters far worse than me..."
"...or the Nine-Tails."
That day, Uzumaki Naruto disappeared, and with it, the Fifth Hokage made a public declaration involving his status as a jinchuriki.
When Jiraiya took some time off his writing to meet with the Hokage about this decision, one explanation was all it took, and everything was understood... perhaps the "key" to the Nine-Tails' power was not the key either Jiraiya or his student the Yondaime Hokage thought it would be...
And even when eons had passed, and the story of the Era of Ninja passed from history to myth - and from myth to legend - there still remain rumors that somewhere, in the former Fire Country, lies a small estate run by a young man with red eyes.
Said young man was often used as the boogeyman to keep people on the straight and narrow, but you wouldn't notice it from him at first glance.
"I'm never going to finish. Not while there's people like them in the world..."
"You will never finish," the fox admonished him. "Never. That is the price for your... no, our power. We will be doomed to remain in this world, a force to cull the betrayers, the blackmailers, the exploiters, the damned..."
"The meaning has long since been lost."
"No, the meaning still remains. We are here because... the world still requires us."
"And so we stay, Kurama... and so we stay."
A man reached out to grab the young woman's shoulder...
...only to find that the woman was no longer there.
Neither was his hand.
"I know what you were planning," a voice said.
"Not tonight... or any other night, for that matter."
The man strained to see into the darkness, only to look into two of the most frightening red eyes ever.
He never saw the Rasengan that turned his head into mush coming.
End.
author's note: Yes, this is an intensely venomous hate fic. Yes, you should easily guess what I'm hating in this fic. And yes, you should probably drop me a line about this, if you think you could add something to it.
If you still don't get what happened, Naruto acquired the power of infinite vision (omniscience, basically) from the Nine-Tails rather than go on a rampage when Jiraiya used the "key". And yes, he found out that one of his "precious people" was not only a stalker, she was also a bona fide pervert.
2013/09/07 edit: Changed the Nine-Tails' name to conform to canon.