Sasuke pushed himself away from the wall. “Naruto, can I talk to you for a moment?”

Naruto hastily got up, only barely remembering to create another shadow clone so that he could teach Temari his Poor Man’s Flying Thunder God technique at the same time. The interior of the Naka Shrine shifted around him, and then he was following Sasuke to a dark corner of the hall. He did not look forward to receiving whatever lecture Sasuke had in store for him, but it was far preferable to having to stay there with Temari. Strangely enough, he knew that he would end up remembering the whole thing when his cloned body dispelled regardless, and yet it still felt as if he was escaping responsibility.

The two of them entered into a small alcove, and stopped there. “Sasuke? What is this ab-”

All light drained from the world as Sasuke formed the seals for the transformation technique, and pure darkness washed over Naruto like a wave. Not a second later Naruto could feel the floor give way beneath his feet, and he fell into a black abyss. There was a faint sound above him of large stones scraping together, and then the only thing that could be seen was the red of Sasuke’s Sharingan.

“Sasuke?” Naruto tried to scramble backwards, but his back was pressed against a wall. “What…”

The red eyes seemed to turn away. A moment later a crimson flame blazed into life inside a nearby brazier, casting the young Uchiha in orange hues as the fire basked him in a warm glow.

“Sorry about that,” Sasuke said as he set to ignite a second brazier. Its flames made a soft rustling sound as they began to lap up its contents. “I had to make sure the others couldn’t listen in on us.”

“Where are we?” Naruto clambered to his feet and looked around guardedly. The walls of the underground chamber were painted with yet more flowing crimson strings, creating the impression of a battlefield in flames, though this time the fire was anointed with floating white clouds and silver wings.

“My family used to meet here in secret,” Sasuke said softly. “An underground meeting place inside of a sealed temple, for when they needed to keep something hidden even from the rest of the clan. I didn’t find out about it until it was too late to ask.” There was a stone tablet displayed against the far most wall, right in the middle between the two glowing braziers, and Sasuke gazed at it with an inscrutable look in his eyes. “I’ll acknowledge you, Naruto. You might be an idiot in other ways, but when it comes to unconventional thinking there’s none better. If there’s anything you can tell me about the Sharingan, or about the history of my clan, I would be… grateful.”

Naruto eyed him warily. “It would help if you’d start by telling me what you already know.”

“I assume you’ve already figured out the basics,” he said. “The Sharingan awakens in times of emotional stress, and it only becomes stronger the more you endure. You start by being able to see chakra, but you can also learn to cast genjutsu with it the way Kakashi taught me. It doesn’t actually let you see the future – that’s just a lie we made up to hide its true abilities – but it does help you predict your opponent’s movements based on small changes in their stance and muscles. It can’t copy techniques either: It’s just easier to learn them when you can watch their chakra change as they are casting theirs.”

“I see,” said Naruto.

“There’s more to it though,” said Sasuke. He kept staring at the stone slab with his Sharingan as if he were expecting it to come to life. “My ancestors, Uchiha Indra or possibly even the Sage of the Six Paths himself, left this tablet behind for us. It’s inscribed with text written in pure chakra, and the more your Sharingan advances the more of it you can read. It talks about a way to develop your Sharingan into an even more powerful, stronger version known as the Mangekyō Sharingan, though the details of what you can do with it are unreadable unless you’ve already attained it.”

Written in chakra? Now that was interesting. Chakra was supposed to dissipate over time, but Naruto supposed that the tablet could have been treated to hold chakra in the same way as his chakra-forged ninjatō.

“We could have Hinata or Neji take a look at it,” he said. “The Byakugan is supposed to have better insight than the Sharingan, after all.”

Sasuke shook his head. “It’s not that simple. The Sharingan interprets chakra in a specific way in order to translate it into visual stimuli. The Byakugan wouldn’t be able to make sense of it.”

That did not actually mean it could not be transcribed and translated separately, Naruto thought, but he let Sasuke continue. In the back of his mind however, the implications of only known text left behind by the Sage of Six Paths kept churning.

“It says that in order to awaken the Mangekyō, you have to pay a certain… price,” Sasuke said. “To gain power, one must sacrifice what is most precious to them.” He clenched his hands, and Naruto did not think he was even aware that he was doing it. “He made his first sacrifice when he killed his best friend, Uchiha Shisui. They found his body in the Naka River with a suicide note written in his own handwriting, but everyone knew that it had really been him. My father must have invited him to one of the secret meetings, and that’s how it all started.”

Naruto swallowed, but said nothing. He had this terrible sinking feeling, like he already knew what was really going on before he even had the necessary knowledge to truly know it.

“Upon attaining the Mangekyō, new powers awakened within his eyes.” Sasuke’s voice had dropped to a whisper, and his red eyes had taken on a haunted, hollow look. “The inextinguishable black flames of Amaterasu, said to be able to burn even fire itself, and the unbreakable genjutsu known as Tsukuyomi.” He turned and motioned at the images of divine fire painted all around them. “Once you look into his eyes, it’s all over. Seconds turn into days, and days into years as he controls all sense of time and space within your mind. There is nothing, nothing…” He swallowed. “Nothing you can do. It’s said to be the ultimate genjutsu, next to Shisui’s Kotoamatsukami, which could be used to permanently change a person’s mind, though that one can only be cast once a decade…” Sasuke’s hands were trembling at an unsustainable rate now, and his whole body was shaking. His eyes no longer looked anywhere at all.

“Sasuke, stop.” Naruto tried to place a hand on Sasuke’s shoulder, but the Uchiha flinched and slapped Naruto’s arm away before it could reach. “You can stop now,” Naruto urged him again. “I think I’ve heard enough.”

Sakura should be here for this, he thought. And yet, somehow, he suspected that Sasuke was glad that she was not. It was strange to think that Sasuke was somehow more willing to show his feelings to Naruto than to the girl he claimed to love. He could not pretend to make any sense of it.

“The Sharingan,” Naruto said, “I think… I mean, it’s pretty clear that it works by expelling chakra from the eyes. I used to think that it might just see chakra by being more sensitive to light, but the fact that you can use it for genjutsu clinched it. And that means it’s really just another tool to cast techniques with, only instead of forming hand signs you use those black markings on your eyes as the physical component. The fact that Uchiha It- I mean, the fact that that man uses it to cast genjutsu and fire techniques, both of which he already knew how to do beforehand, kind of settles it for me.”

Sasuke blinked, his expression still seeming strangely empty. “You’re saying that the Mangekyō doesn’t give you new techniques at all? Then why does it have unique eye patterns for each user?”

Naruto considered this. That did seem strange, but he had to remember that Sasuke was basing his knowledge on hearsay, old traumatic memories and a cryptic text upon a thousand year old rock.

“Alright,” he said, “let’s go through the possibilities. Those who acquire the Mangekyō were said to develop unique abilities as well as unique eye patterns, correct? So either the latter causes the former or it’s all a coincidence and the pattern means nothing.” Normally this would be the point to run some tests to distinguish the possibilities, but that was not exactly practical in this case. “What about his eyes? You said that he awakened two new abilities, right? Did he also have two separate patterns in his eyes?”

“No,” said Sasuke. “It was the same in each. A hooked wheel with three spiralling curves.”

“Then the two must be unrelated,” said Naruto. “If the eyes look the same then probably the Mangekyo does let you cast more powerful abilities, but they still have to be learned and practiced like any other technique. In that case, maybe the patterns change because you only develop the Mangekyō when you try to force out a technique which requires that level of power, or… no wait. Let me think.”

He closed his eyes and allowed his thoughts to flow over him the way Kakashi had shown him after the disaster in the Land of Waves. Stick to what you already know. Don’t try to come up with explanations just yet. Let the answer to the riddle follow naturally from the facts.

Fact: The Sharingan becomes stronger from stress. The Mangekyō requires even more stress to awaken.

Question: Why does it need to be awoken at all? What disadvantage is there to having more power?

Follow-up question: What other examples of powers requiring stress to unlock are known?

Answer: Only the Eight Gates technique, which enhances your power at the risk of hurting yourself.

Fact: The Sharingan works by expelling chakra through your eyes.

Fact: You need eyes to see things.

Also fact: The Sharingan is known as the eye of misery and madness.

Naruto’s eyes flashed open. “It uses the Gate of Opening,” he said. “The one located in the brain that Kakashi and Rock Lee also know how to activate. Your body normally limits your flow of chakra to avoid hurting yourself by accident, but you can override that with enough adrenaline and, well… emotional duress.” He looked cautiously at Sasuke, who seemed to be taking this in without much reaction.

“You’re saying that anyone with the Sharingan who has mastered the First Gate can awaken the Mangekyō? So all that stuff about having to kill your best friend – that was all a lie, then?”

“Well, an experience like that might help you do it by accident,” Naruto said, “so the guy who inscribed that tablet was probably not lying. But Sasuke, this whole thing sounds stupidly dangerous. I know I tattooed an explosive seal onto my palm, but this is your brain we’re talking about. Trying to forcibly override the inhibitors in your head in order to shoot black fire out of your eyes does not seem smart.”

“No,” said Sasuke, still in a daze. “I suppose not.”

“Right,” said Naruto. “So in that case, Amaterasu is probably just a more powerful fire technique that somehow… feeds on the chakra of everything it touches, including other fire techniques? And Tsukuyomi works by massively accelerating the target’s brain as well as your own, which is really incredibly powerful when you think about it.” He took a deep breath. The implications of such a technique were already enormous, but he had not even gotten to the truly important part yet. “That just leaves the last Mangekyō technique you mentioned. Kotoamatsukami.”

Sasuke looked at him warily, perhaps sensing something in Naruto’s tone. “What about it?”

“You said that it gives complete control over the target’s mind, with as downside that it can only be used once every ten years. Leaving aside the fact that no other jutsu we know of has a limitation like that, how could anyone possibly know that?”

Sasuke froze. “It would have to have been used at least twice, but Shisui was only seventeen when he died.” Some of the same horror which Naruto also felt was creeping into his eyes and voice now. “Someone else must have learned the technique before him. Perhaps his grandfather, Uchiha Kagami…”

“Then how come there’s no record of it ever being used? And more to the point, who would believe something that convenient? Sasuke, imagine you’re the Hokage. One day the Uchiha clan, which is known to hold secret meetings and lie about their true power, turns out to have access to the ultimate mind control technique. But don’t worry, they say, it can only be used once every ten years. Also, only one of us can use it, and oh look – he just died.” He looked Sasuke in the eye. “Sasuke, if your father had access to a technique like that, who do you think he would have used it on?”

“The Hokage,” Sasuke said. He stumbled back within the narrow room, his left arm nearly passing through the flames of the brazier as he went. “No wait. No, he wouldn’t, because that’s not what I would do. The very first thing you would do if you had access to a mind control technique… oh Sage.”

“Exactly,” said Naruto. “The first thing you would do is to mind control the other people who also have mind control techniques. That includes Ino’s clan, who are very blatantly just using advanced genjutsu techniques to read and twist the minds of others because that’s literally all any of this mind control stuff is.”

Sasuke fell back against the wall opposite Naruto, the flickering braziers casting him in shades of dark orange. “My clan would have been a threat to the entire Village. So they pinned the blame on Shisui and made up some fake limitations to keep the Hokage from panicking while they figured out what to do, but then later they were all killed anyway. Because by that time the Council had figured out, or because somebody told them, that there is no such thing as inherited techniques at all…”

“By Uchiha Itachi,” said Naruto, “who was a captain of the Anbu. Together with his subordinates. And the entire rest of the Anbu forces, most likely on the orders of Lord Danzō and the Third Hokage both.”

Sasuke sank to the floor, his head resting against the wall amid the images of crimson strands and holy fire. “There were bodies, all over the streets, that night. There’s no way… there was simply no way that nobody in the Village noticed…”

Naruto remained still, once again left without any words to say. If Sakura had been there, perhaps she would have been able to make things better somehow, but Naruto had never had that power. It was just like back in the village of the ice and snow, when he had been unable to do anything to save the old bridge builder. It seemed that this time would be no different.

“You’re wrong,” Sasuke rasped. “That’s not what happened.”

Naruto looked up. “What?”

“Kotoamatsukami. There’s no way they would have let such a power go to waste. If you’re right then anyone with a Mangekyō could learn it, and the person who did is responsible for everything.”

Responsible for everything. The words hammered into Naruto’s skull. He had not even thought about it that way yet, but of course all of this had to be linked to the attack on Konoha all those years ago. First the Enemy had wiped out the Uzumaki clan, who were known as the greatest seal users of their time. Then they attacked the Leaf in such a way that only the Fourth Hokage could save it by sacrificing himself to seal Kurama. And then, less than a decade later, they arranged for the Uchiha clan to be wiped out so that they alone would be left with the power to control the minds of others.

“You assumed that everyone who could use Shisui’s technique was killed before the coup could take place,” Sasuke continued. “However, what if that’s not the case?” The Sharingan had faded from his eyes, but when he looked at Naruto his black eyes gleamed just as darkly. “You said that the first thing you would do is to mind control anyone with the same ability. But what if you’re just one person and you only just learned this new power from your closest friend? Even if all the other restrictions are a lie, using the Mangekyō still comes with risk. What would you do in that case, Naruto?”

“You would… you’d want to make sure nobody else can use it before you do.” A horrifying vision appeared within Naruto’s mind as his brain instinctively answered the question of what he would do if he lacked any sense of morality. “You’d take advantage of your status as an Anbu captain and get permission from your superiors to kill your best friend first of all, and then you’d use Kotoamatsukami to convince the Council to give the order to slaughter the rest of your clan. And then once you controlled the Council, you’d mind control Akatsuki and use them in order to take over everything else.”

“Yagura would have been too powerful to control, being host to the Three-Tailed Beast,” Sasuke said. “So instead he installed a puppet ruler and took over the Land of Water that way. The attack on the Hokage tower was probably done for the same reason, which means the Third himself might not be fully under his control just yet.” He stood and started pacing around, hands clasped behind his back as he circled the small stone room. “He’ll have left some minions behind in Konoha, just in case. He could have easily implanted the spare Mangekyō Sharingan from Shisui into anyone he already used Kotoamatsukami on, and instructed them to mind control anyone else who might cause any trouble.”

“Like Danzo, you mean?” The enigmatic commander of the Root Anbu forces was an obvious candidate for mind control, and not only because the bandages around the right side of his face could easily hide a Sharingan. “Who’d be the second? It’d have to be someone who has his eye obscured somehow…”

Naruto trailed off. Sasuke was looking at him like he was an absolute idiot, and a sick feeling welled up within his stomach as he realized why. “Sasuke, you can’t really think…”

“Of course it’s him,” Sasuke spat. “Who do you think the superior was who Itachi asked for permission to kill Shisui? Who do you think led the slaughter of my family that night? And where do you think that bloody nickname of his came from in the first place? Cold-Blooded Kakashi, the Friend Killer?”

“But… that was just because he let his friends die at the Kanabi Bridge,” Naruto protested. Kakashi could not actually have gotten his eye from the Uchiha massacre: The timing simply did not add up. Unless, of course, the stories about him having the Sharingan before that were all just a lie…

“You mean that ridiculous story where his friend happened to die in such a way as to conveniently leave him with just one Sharingan? Even if that were true, Itachi could have simply used Kotoamatsukami on him and transplanted Shisui’s eye afterwards. It’s exactly the sort of twisted logic that man would come up with: Nobody would ever think to look for a Sharingan in the eye socket of a man who already had one.”

Naruto’s memory flashed back to the stories Kakashi had told of that day, back when the three genin had accompanied the bridge builder on his journey to the Land of Waves. Their teacher had never actually explained to them what happened, only said that it was for them to figure out, and it was only now that Naruto realized that Kakashi himself might not remember. If he really had been mind controlled as Sasuke said, then all of that might have been some hidden part of his personality desperately pleading with his students to realize the truth…

Naruto swallowed. “You’re just making assumptions. We don’t actually know if any of that stuff is really true.” Though even as he said that, he realized that Shisui’s eyes had to be somewhere. Sasuke was right at least that the Council would not have let such power go to waste. And the same logic applied to all the Uchiha clan’s regular Sharingan: If Kakashi had been able to implant one, there was no way they would not at least have attempted to repeat his success. “Even if you’re right about the coup, Kakashi-sensei left the Anbu a long time ago. There’s no telling if he was even around for the massacre.”

“You don’t leave the Anbu,” Sasuke almost shouted. “No one ever leaves the Anbu! You really think it was a coincidence that he of all people was assigned to be our teacher? This entire time he’s been tasked to spy on us, to keep us alive in case we’re needed while alerting the council if we’re going to become a problem. In fact, if your angry rants against Konoha’s leadership had been any less ham-fisted and over-the-top we probably would have all been killed by now.”

Naruto hesitated. There was truth to what Sasuke was saying, far too much of it to just ignore, and yet… It could not actually be the case that Uchiha Itachi was behind everything. For one thing, he would only have been six when the attack on Konoha happened. Even if it was the other way around and Kakashi had been the one to mind control Itachi, fifteen would still have been far too young to-

He stopped. To do what, exactly? Use the Sharingan to cast a genjutsu on Naruto’s mother and unleash Kurama upon the Village? Have Anbu-like knowledge of the Leaf’s defences? Spread news of a crisis far away from Konoha so that Jiraiya would be away on a mission when it all happened? Arrange for a shadow clone to create an aura of darkness using an academy-level technique to make it look like Uchiha Madara was behind it all, and then dispel his cloned body when he was about to be caught?

All this time Naruto and Jiraiya had assumed that the Enemy was some ancient and powerful ninja, but there really was no proof that that was actually the case. What if they had been on the wrong track all along?

The flames of the braziers rustled softly.

“No one can know of this,” said Sasuke. He had his back turned to Naruto and was once again looking at the stone tablet, the twin braziers burning brightly on either side of him. “If anyone were to find out what we know, the Council would be on us in an instant. Everything… everything would be for nought.”

“I know,” said Naruto. The words in his father’s letter ran through his head once again. The most important skill for any ninja to possess is the ability to remain hidden. “I won’t tell anyone, I promise.”

“It’s not a matter of choice,” said Sasuke. “Ino’s clan is able to read minds, and you’re definitely right that anyone with sufficient genjutsu skill can learn the same ability. Plus you already attracted the attention of the Council, and any number of them has reason to want to sift through your thoughts.” When Sasuke turned around the Sharingan was blazing a furious crimson, and Naruto took an involuntary step backwards. “Fortunately, you’re only a clone, and I already know from your fight against Gaara that your memories don’t return to your main body if all of your chakra is expended at once.”

It took Naruto a second to process the words, and then he opened his mouth to cry out. “You bast-”

The Sharingan burned into Naruto’s skull, and the last he felt was the flash seal on his palm flaring into life as he faded into nothingness.