Archive of Our Own

When Killua first gained consciousness, he was surrounded by warmth. He squirmed as much as he could, but he was trapped completely.
Killua attempted to access his nen, but it was barely there, only enough to keep him alive. He’d seen toddlers with more nen than he had.
He was stuck.

Killua realized what happened to him a few months later when giants named him Sasuke.
Life had only ever been kind to Killua when it presented him with Gon.
Figures it’d cling to him.

“Nii-san,” Killua began one evening during dinner, “You’re a killer, aren’t you?”
Mikoto and Fugaku froze, their eyes locking on their two-year-old. Itachi continued eating his soba after a brief pause.
“I’m a shinobi, otouto,” Itachi deflected.
“Shinobi?” Killua prompted.
“They protect the village and go on missions for Konoha,” Itachi explained. “They keep it stable.”
“Ah, so you’re an assassin,” Killua surmised.
“No, though assassinations are sometimes part of the job. Ninja do a lot of other things,” Itachi gently disagreed. Killua hummed, and the table fell into silence. After a few moments, Killua looked up from his food again.
“I’ll be a ninja then. It sounds like fun,” Killua decided. Fugaku frowned.
“That isn’t how it should be described. Ninja are important to the clan and the village, it’s an important responsibility,” Fugaku scolded.
“So you’re saying I can’t have fun while doing it?” Killua asked, frowning.
“That isn’t it, sweetie,” Mikoto said. “It’s just that you shouldn’t be a ninja just because it might be fun. There are other parts of it.”
Killua nodded, but his pout- which would probably be a frown, were he older, but for now, it was just adorable- showed his persisting disagreement.

“Why do I need these?” Killua asked, flipping a kunai around in his hand carelessly.
“Sasuke, don’t do that!” Mikoto scolded, making Killua pause his flips, while Fugaku frowned at him.
“Weapons make it easier to fight, Sasuke. Our bodies lack the sharpness to pierce other things efficiently, so it’s supplemented with ninja tools like that kunai. And you can target opponents who are further away from you without having to get close,” Fugaku lectured.
Killua tilted his head thoughtfully, glancing at his hands for a moment before looking away.
“Whatever,” he allowed.

Killua first met Shisui on a sunny day where he was training in a forest owned by the Uchiha. Kids weren’t held on a tight leash around here, unlike when Killua was a Zoldyck, and he could go anywhere on Uchiha land as long as he never left the compound. So he found himself frequenting the forest, reading up on the world and practicing his chakra and nen. Killua found that nen was chakra, but just a small part of it. Chakra opened up new horizons for Killua, and while he would always use nen, chakra was definitely something he’d add to his arsenal. It was just so versatile!
“Damn, kid,” a teenager said with a whistle from up a nearby tree, startling Killua out of his concentration on his kunai, which he’d been lacing with lightning chakra then throwing it. He was trying to get the chakra to last through longer distances, so it would be easier when he finally got a yoyo commissioned and could lace that with his chakra. Killua had a lot of time on his hands as a five-year-old, and improving old techniques and making new ones were fun. But kunai’s were definitely far from his favorite weapon.
Killua snapped one of his charged kunai towards Shisui at a startling speed, though Shisui simply leaned to one side to avoid it. What was really notable, however, was how easily he matched the kunai’s speed.
“It’s bad manners to sneak up on people,” Killua griped, scowling.
“Well, I don’t think anything could’ve distracted you, little guy,” Shisui placated.
Killua scoffed, but rescanned Shisui’s appearance, his eyes catching on the silver headband.
“You any good?” Killua asked, curious. He was fast, at the very least. Shisui chuckled.
“I’d like to think so, chibi-chan. Wanna test that out?”
Killua’s eyes narrowed at the demeaning nickname but gave a curt nod. There weren’t many he had a chance to spar with, and all of them weren’t even in their double digits. Granted, the same could be applied to Killua based on appearances, but he was still a pro hunter and assassin.
Needless to say, his peers never could keep up with him.
Killua answered Shisui’s question by sending a volley of charged kunai his way.

Shisui was kinda weird, Killua quickly decided. They had begun lightly, with Shisui just dodging kunai and Killua improving his speed and aim little by little on the field. Soon the field was filled with the crashes and zips of kunai at a quickening tempo. It wasn’t until the pair were fifteen minutes into their spar that a kunai grazed Shisui’s arm. Shisui stopped, impressed, and Killua took the cue to pause the spar.
“You out after just a little scratch?” Killua taunted, twirling his kunai around. Shisui looked up from his arm, shooting a bright beam at Killua, his eyes crinkling around the corners.
“You landed a hit!” Shisui exclaimed, holding up his arm to show off the bleeding cut.
Killua’s eyebrows furrowed in confusion. “So?” He asked, peering down at it. “It isn’t even that deep.”
Shisui’s chin tilted to the side, as if confused. Then his eyes widened in understanding, and he somehow did the impossible and grinned even wider.
“Kid, I was using my shunshin at top speed. And I’m Shunshin no Shisui.”
“Shunshin? Is that a jutsu?” That would explain the chakra he felt coming from Shisui during the spar.
“Yeah, it enhances speed, and I’m famous for it, but that isn’t the point. I’m known as the fastest shinobi in the history of the leaf after the Yondaime and Nidaime, and you landed a hit on me! Great job!” Shisui complemented. Killua frowned harder.
“So you’re…trying to boost my ego, then?” Killua inquired, looking a little lost.
Shisui couldn’t help it. He burst out laughing.

Shisui took Killua home that night, the latter hanging off Shisui’s back, barely maintaining consciousness. The pair had trained in hand to hand after that, and worked on developing Killua’s muscle memory and physique.
Shisui knocked on the door of Killua’s house eventually, and Mikoto answered. She surveyed the pair and nodded at the exhausted Killua like nothing made more sense to her than the sweaty, dirty body clinging off Shisui’s body.
“Anything I should be worried about?” Mikoto asked as Shisui deposited him in her arms.
“No, he’s just tired. Gotta say though, your hands are full with this one,” Shisui replied with a grin.
Mikoto sighed, but it was one of fondness. “God knows, I’m aware.”

“So?” Itachi asked Shisui, confused. The two were sitting together above the Naka River, their legs hanging off the cliffside. The two had just finished their own spar, which were getting less and less frequent as Itachi got immersed in Anbu. The two cherished the time they had together, in a way only best friends could.
“Does he train by himself a lot then?” Shisui questioned. Itachi nodded. Shisui frowned, thoughtful. “Have you ever trained with him?”
Itachi shook his head. “He asks every year, the day after his birthday. I’m pretty sure he knows that I’m waiting until he’s older to teach him anything at this point. Why?”
“He was…advanced. Like, change in chakra nature, advanced. And he landed a hit on me at top speed.”
Itachi’s eyebrows steadily climbed his forehead, though subtly. It was as surprised as Itachi could look. “He landed a hit?”
“Yeah. I found him training alone in a field, and he’d covered his kunai in lightning chakra, kind of like Asuma’s trench knives. Anyway, the two of us ended up sparring after that, and he improved with every throw. I’ve never in my life seen anyone improve that fast, not even you, ‘taichi.”
“Oh, Sasuke,” Itachi sighed, and Shisui mirrored his grim expression.
The fate of a prodigy was never a good one. It was a truth the pair knew intimately.

“Sasuke, can we talk?” Itachi began ominously, standing in the doorway. His posture was forcibly relaxed, even though not many could tell the difference between anxious Itachi and calm Itachi.
Itachi could count on one hand the number of times he’s gotten anxious, though.
“Sure,” Killua agreed, picking up on Itachi’s body language. If Killua hadn’t lived with Itachi for the last five years, he wouldn’t have picked up on the practically non-existent serious edge to his cool posture. Itachi always seemed a little serious and was extremely mindful for an eleven-year-old, but not this serious.
Itachi needed to loosen up a little, in Killua’s opinion.
Itachi settled on the wooden floor in front of Killua, looking every bit the responsible older brother. Killua only highlighted it with his sheets tangled around his body and his pillow bracing his stomach instead of his head. He had an upturned book on the floor which he had been reading prior to Itachi’s arrival.
“What’s up,” Killua asked casually, as if his brother did this all the time.
“Shisui told me about your spar,” Itachi carefully articulated.
“You know him?”
“Yeah, we’re friends.”
“Huh, wonder what you see in him.”
Itachi ignored this, pressing on. “And he said that you know some…advanced techniques. Where did you learn them?”
Killua leaned forward, resting his elbow on his thigh, and his head in that hand. “The lightning chakra kunai? I learned about it in a book. Change in chakra nature and stuff. There was this thing under wind chakra with something similar. Thought it might work out. Why?”
Itachi exhaled, then continued. “And the chakra conducting kunai? Where did you get them?”
“The Uchiha armory. Security’s pretty lax there, and if it didn’t benefit me I’d probably tell father about that.”
“You…snuck in. Okay,” Itachi nodded to himself, much like his mother had when Killua had returned from the aforementioned spar.
It looked more like he was trying to convince himself of that though.
There were chunin guarding that place, after all.
And Sasuke is five years old.
No. Itachi needed to focus on the issue at hand.
“Sasuke,” Itachi’s voice was firm, that of a commander. The image was ruined by the concern in his eyes, however. “You cannot, under any circumstances, let anyone know how far along you are. Not father, not mother. No one. Don’t let anyone see you train either. Just, just until you at least graduate from the academy. Please.” His voice grew more and more exhausted as he went on.
“Why?’ Killlua prompted shortly.
“Because,” Itachi’s pleading eyes met Killua’s, and Killua wanted to look away from all the intense emotions swirling in him but was locked in place. “You deserve to be a child, Sasuke. The life of a prodigy is a lonely path, and I don’t want you to live it.”
And then Killua saw Itachi, really saw him. Killua’s mental image of a cold older brother who cared more about killing than his home life. The older brother who hid his dislike of his father, faking being happy around him. The older brother who ignored those who didn’t catch his interest and did his very best to control those who did.
And in that cold older brother’s space entered Itachi. Itachi, the warm older brother who didn’t want to be a shinobi. Itachi, who hated their father’s cold expectations. Itachi, who wants only the best for Killua. Itachi, the lonely genius who graduated from the academy at seven.
Itachi, who loves Killua more than anything else.
And, above all, Killua realized the most important thing about Itachi.
He wasn’t Illumi.

When Killua enters the academy, Itachi isn’t there.
Father isn’t there either, but that’s only because Itachi knew Killua didn’t want him there. Otherwise, Killua’s pretty sure Itachi would’ve blackmailed him into it.
No, only his mother is there, standing with the other parents and waving when Killua looks her way.
Killua…likes his mother. She’s soft, in a way his mother never was. It’s a bit annoying, sometimes, because it was hard for Killua to build pain and poison resistance with her around. She refused to hurt Killua, and while she slipped poisons in his food to help him build resistance, she never did it if the side effects were anything more than a cold.
Killua had to go out of his way to remedy that. He found it strange that she would help Killua with anything but training, but he could do it on his own too. It was sometimes like an adventure, trying to find all the poisons the village had and build resistance to them. In the process, he’d been pretty much everywhere important in the village. The hospital, ANBU headquarters, ROOT headquarters, Orochimaru’s old hideouts in the area… He’d almost gotten caught a couple of times, but it doubled as stealth training, so Killua enjoyed it.
But besides that, she was nice enough. She gave Killua all the books he wanted, even the ones that were way above his jurisdiction. From books on iryoninjutsu to history books, Mikoto provided what he wanted at his request. She treated training injuries he got without question as to how he got them, knowing he wouldn’t tell. She cooked all his meals instead of leaving it to a servant. She gave him a hug every time he left the house and came back, and always asked how his day was if he came home late.
So Killua was fine with her deciding to come to his entrance ceremony.
The ceremony itself, however, was extremely boring. The hokage went on and on about the honors of being a shinobi, patriotism, the ‘will of fire’, and similar propaganda. Killua didn’t pay attention to him for more than a couple of seconds, his eyes instead scanning his classmates.
He quickly picked out the clan kids, finding a member of every single powerful shinobi clan of the leaf at least once. A few were even clan heirs, like the Hyuuga’s, the Yamanaka’s, the Nara’s, the Aburame’s, and the Akimichi’s.
All of them would probably be in his class. Maybe he’d even get to see a few clan techniques in action, that’d be fun.
But first, he had to wait out the old man's speech.

“My name is Uzumaki Naruto, and I’m gonna be hokage one day, dattebayo!” A blond boy proclaimed from the front of the classroom. The class stared at him in silence, then broke into hoots of laughter. Jeers and taunts were thrown the boys' way, and the sensei yelled at everyone to quiet down. Killua watched on, intrigued.
From his understanding, a kage was like the chairman of the hunter association and a country's dictator combined. Konoha’s kage was the hokage. It was simple enough, and a job that sounded extremely boring and undesirable. What’s the point of being the strongest in the village if you don’t get to have fun? Seriously, just look at the old man.
So Killua wondered why such a spirited kid would want such a dumb job.
The introductions went on, and eventually, Killua’s turn began. The instructions were to state your name and dream for the future. It was simple enough.
“My name is Uchiha Sasuke, and I want to have fun,” Killua introduced shortly, then returned to his seat, leaving behind his confused teacher and classmates.

Later that week, Naruto announced Killua as his rival.

“Shisui.” Killua had let up on his chakra version of Godspeed, silently signaling a pause in the spar.
“Yeah? What is it?” Shisui asked, wiping some sweat from his brow.
“You and Nii-san are hiding something, something big.” It wasn’t a question. Shisui froze. “It wouldn’t have anything to do with the growing tension in the clan, would it? Or the amount of ANBU stationed around the compound?” He flicked a kunai casually in his hands.
Shisui loosened up and smiled. It didn’t reach his eyes.
“What’re you talking about? Everything’s fine.”
Killua sighed in exasperation, and reactivated godspeed.
“Idiot.”

Killua’s eyes narrowed from the rafters of the Uchiha Clan hideout, and slipped out silently, deactivating zetsu.
A coup, huh.
Itachi and Shisui were definitely against it, the damn pacifists.
He stretched out his En, which had considerably grown through all the training he had in the last seven years, even compared to what it was when he was still Killua. He was working on chakra sensing as backup, but his En would probably always be his go-to tracker.
He found Shisui in a nearby forest with Itachi, but he was bleeding heavily and in his hands was an…
Shit.
Killua activated his Godspeed like it was second nature. It practically was with how often he trained with it. He was at their side in seconds, just in time too, as Shisui had fallen back. Killua barely glanced at Itachi, whose arm was stretched out and was equipped with bleeding eyes. He jumped off the cliff right after Shisui and ran along the cliffside, so fast that he didn’t need to use chakra to stick to the walls. He soon had Shisui in his arms and raced him back up the cliffside.
“Do you know any iryoninjutsu?” Killua shot out at Itachi as soon as he returned.
Itachi nodded, in a state of shock, “Only the basics that are required for ANBU,” he whispered.
Killua clicked his tongue. “Make a shadow clone then, I don’t have the chakra for that and healing him. Now!” He snapped when Itachi didn’t move. Itachi’s hands went up, and beside him appeared two perfect shadow clones. “One of you, get boiling water, alcohol, and a towel. Another, beat his heart for him, he’s been poisoned, and it’s failing. And the last one, take care of his eyes. I’m taking out the poison,” Killua spat out, all the while working.
He’d stripped off Shisui’s top and headband quickly, made a cut in his chest, and was beating his heart for himself. An Itachi soon took that over, one shunshined away, and the last one began a basic Shōsen (mystical palm) jutsu over Shisui’s empty eye sockets. Killua himself summoned his water bottle from one of the storage seals on an armband he got for his birthday and began removing the poison from his cuts in order of priority.
In all his focus on healing Shisui, Killua ignored the stinging of his eyes and the sudden clarity in which he saw the world, even though a little part of him knew what it meant.

The next few hours were a blur, but eventually, Shisui stabilized. Killua looked up at Itachi, exhausted. Itachi himself looked just as bad. Killua debated a moment as to if he should get the story now, or later, after sleep. But there were probably things they needed to talk about, and there was a chance they were things they couldn’t put off, no matter how tired they were.
“Itachi.”
Itachi’s face fell, and he looked to the side. “Can we do this later?” He almost sounded whiney. Almost.
“No.”
So Itachi explained. He tried to start with the coup, even then leaving out details, which Killua quickly put a stop to.
“Stop. You and I both know that isn’t all. Start over, and tell me everything.”
He explained, for real that time, letting Killua know about everything Itachi thought he didn’t know. While some things were things he did know, including the clan’s coup idea and his place in ANBU. Though when Itachi started to explain ANBU, and later ROOT, Killua stopped him, telling him he already knew. Looking deeply disturbed both times, he continued. How he and Shisui went to the hokage, how the hokage had not even attempted peace with the Uchiha, how Shisui was assigned to spy on Itachi, and eventually, how Danzo tried to nab Shisui’s eyes.
Killua’s first thought after that was 'what a pain.'
His second thought was, 'let’s kill Danzo then.'
“No, Sasuke, just. No.” Itachi’s voice did in no way hide his exhaustion. Oh, Killua had said that last part aloud.
“Why not?” Killua whined, rolling with it. It was a valid idea.
“Because there’s a reason Danzo’s lived through two wars.”
Killua scoffed. That was no reason not to go for it. “Whatever, we’ll talk about that later. Right now, we have more pressing matters at hand,” Killua dismissed, gesturing at Shisui’s unconscious body. Itachi frowned.
“We need to report this to the hokage,” Itachi murmured.
Killua couldn’t help it. He snorted.
“What?”
“Itachi, you literally just told me that the hokage hasn’t even attempted peace talks with our clan. And if that was all, then maybe the clan would have a chance, but Danzo’s got the hokage wrapped around his finger. He’ll either deny Danzo did this or just ignore it completely,” Killua deadpanned.
Itachi frowned harder. “There’s no way the hokage would overlook something this big, even with his personal bias.”
Killua shook his head, a frown of his own crawling onto his face. The propaganda had obviously done its job on Itachi. But hopefully, Killua can fix that.
“Itachi, about that…”

Shisui woke up to his head pounding ruthlessly. His eyes flashed open, but he didn’t see anything.
That was probably because he’d pulled out his eyeballs earlier, though.
But wait, he also jumped off a cliff earlier, so shouldn’t he also be dead?
Unless he was dead.
His head gave a jab of pain, and Shisui grunted.
Who knew being dead hurt so much?
“Is anyone here?” Shisui asked the empty(?) space around him hoarsely.
Damn, some eyeballs would be pretty great right around now.
“It’s about time,” a boyish voice muttered. He continued, louder, “‘morning Shisui, I don’t suppose you grew some brain cells while you were asleep, hm?”
Shisui would know that bratty tone anywhere.
“Sasuke? Is ‘at you?”
“No, I’m the shinigami who took the form of your greatest fear. Though I gotta say; seriously, a seven-year-old? You can do better than that,” Sasuke(Shinigami-san???) said.
The worst part was, Shisui wasn’t even sure if Sasuke/Shinigami-san was joking or not.
Maybe that emotionless drawl was hereditary? God knows he’s heard it more than enough from both Itachi and Fugaku.
Shisui despaired at how those two were corrupting poor, sweet, innocent-
“Oi, are you listening? Friggin…ugh. ITACHI!”
Soon another voice entered the room, leaving no footsteps in their wake. Maybe it was another Shinigami? Or a ghost? Ooo, or maybe a ghost who was the Shinigami’s boyfriend? Damn, even ghosts had a more active sex life than Shisui…
“Shisui? Can you hear me?” The second voice asked. Shisui was momentarily sidetracked, before realizing holy shit I’m talking to the shinigami’s boyfriend!
“Hellooo urm, Shinigami-okusan? I dun really know, uh, what I should call you? Oh wow, this is awkward. And surreal. I’m Shisui, nice to meet you,” he introduced, totally forgetting that they had called him by name, “do you think you could get Shinigami-san over there to use literally anybody’s voice but my little cousins? It’s kinda creepy, but in a cute yandere ‘he’s only allowed to spend time with me’ way, y’know?”
Total silence fell in the room. No one moved, no one spoke. Shisui once more broke the silence.
“Did you leave? Was it something I said?” Shisui wondered. And finally, a pshh of laughter, followed by chuckles, and finally guwaffs.
Poor Shisui was just confused.
“I-I’m pretty, pretty sure,” Shinigami-san sputtered out, “that he’s high on pain medicine right now, Nii-san.”

The second time Shisui woke up, he was more cognizant.
He opened his eyes and was once more met with darkness. He locked his muscles in place, and spread his senses out along with his weak chakra sense.
There was one person in the room with him.
Shisui shunshined behind them and brought a kunai to their throat. Normally, he would’ve used his Sharingan to keep them in check, but they were currently unavailable. Shisui hit the back of the person’s knees, and they compliantly fell to the floor.
“State your name and purpose,” Shisui stated coolly, his voice emotionless.
“Uchiha Itachi. I’m currently monitoring your health,” an equally emotionless, incredibly familiar voice replied. Shisui scanned the person’s chakra, and while Shisui wasn’t the greatest sensor, he knew Itachi’s signature best right after his own. As much as Shisui wanted to immediately let him go, Shisui made sure to double-check.
“Who was my first crush?”
“Yondaime-sama,” was the monotone response. Shisui loosened up, giving Itachi some space.
“Sorry about that,” Shisui apologized, sheepish. Itachi hummed his forgiveness.
“How are your eyes?” Itachi inquired while Shisui returned to where he’d been laying down. It was plush, and his hand landed on a loose sheet. A futon, then.
“Eyes?” Shisui repeated, confused.
“Sasuke found a med-nin, and I used a genjustsu on them. They implanted your eyes back in,” Itachi explained. Shisui brought his arms up, palms facing Itachi in the universal hold-up gesture.
“Wait, eyes? As in, both of them? But Danzo has it? And how am I alive anyway? What happened?”
Itachi then gave Shisui a quick rundown of the events after Shisui fell. Sasuke had apparently used his Godspeed to save him, as he’d somehow figured Shisui was in danger. Itachi himself hadn’t been able to get that part out of him, the stubborn kid. Then they worked together to heal them, which also revealed that Sasuke was decent at medical ninjutsu. Afterward, Itachi had told Sasuke about the coup, as he was too deep into it and too smart to not be able to find out on his own if Itachi didn’t tell him. The pair had then returned to the Uchiha district and kidnapped an actual med-nin to finish up his healing and prepare him for surgery. Sasuke left Itachi and the med-nin, citing an errand. He came back an hour later with Shisui’s missing eyeball.
“Whoa, whoa, whoa, wait a minute. He what?”
“He came back with your missing eyeball.”
“So, he just, what, stole it from Danzo?”
And the crazy part was, it started to make sense to Shisui. He had heard from Itachi that Sasuke had been breaking into the Uchiha Armory, and who’s to say that was the only experience he had in both B&E along with theft? Shisui suspected that, with the level of medical ninjutsu required to fix Shisui up like that, he would’ve needed books that Mikoto-baa-chan wouldn’t have had access to. Who knows how many times he broke into the hospital alone?
And where else has Sasuke been?
“That isn’t all, Shisui. Sasuke awakened his Sharingan.”

“Your brother is going to reign hell on the world one day, ‘tachi,” Shisui later bemoaned, letting his face fall into his hands. He felt the bandages around his eyes, reminding him further about how insanely powerful Sasuke already was. The kid was just seven!
“Shisui, I’m afraid he’s already started.”

“He asked you to what?!” Shisui shouted, making Killua shush him. “Sorry, but that’s just…”
“Shisui, I don’t think I have a choice here,” Itachi muttered, and Killua spaced out, thinking of how to work around this.
The three were in a forest near the leaf where Shisui had been living since his supposed ‘suicide’. Shisui had made a hut using doton, and Itachi had gotten him necessities from konoha. They’d decided he was no longer safe there, and he would return when they did something about Danzo. How and when this would happen was still undecided, but if it took too long Killua would just kill Danzo, with or without their permission.
But this, this is a solution that would actually work for a few years… though obviously, Killua would still end up killing Danzo.
“Then let’s just do it!” Killua decided brightly, putting his fist in his palm.
“Sasuke?” Itachi asked, hesitant.
“Well, the order is obviously fake, Danzo probably didn’t go through the hokage at all with this. Even that pushover wouldn’t agree with something this bloody,” Killua said, nodding to himself. “He has the ‘easier to ask forgiveness than permission' mentality. But, poor, loyal Itachi here had no idea about that! He just wants to keep his weak little brother safe, after all.”
Killua had mock sympathy dipping from his voice at this point, and the other two had no idea what to make of it.
“So what’s the hokage to do other than send Itachi out with the weird guy in the woods to spy on a criminal organization? I mean, if they can aid in the massacre of a clan then surely they’re dangerous!”
Then Itachi got it. “You want Shisui and I to leave the village together, don’t you.” Killua shot him a cocky smirk.
“Since you two are so against me just killing Danzo, Shisui’s gonna get pretty bored cooped up here all alone,” Killua explained, gesturing at the hut. “So why don’t you two go out and have some fun in espionage? And when I’m an actual shinobi, I’ll take you two back to the leaf. Doesn’t it sound like fun?”
The two were quiet for a moment, thinking. “But Sasuke,” Itachi said finally, worried eyes looking into Killua’s. “What about you? You’d be alone for years, and I know you’re strong enough to survive, but…” you won’t have us, and we won’t have you, he didn’t say.
Killua smiled, but instead of a smirk, or a shit-eating grin, it was a small, gentle smile. One that spoke of love. His dark eyes poured out love towards both Shisui and Itachi in waves, something neither of them expected from the devilish boy who never really seemed to care about anything other than having fun.
“It’s alright, Nii-san, Shisui. I’m used to being alone.”

That night, for the first time, Killua told someone his real name.

“So, should we call you Killua now on then?”
“Stick to Sasuke, it’d be confusing to make the switch.”
Itachi watched the two begin bickering with a fond smile.

“Nii-san, do me a favor,” Sasuke requested as Itachi walked Sasuke to school the day of the massacre. “Let me kill kaa-chan.”

“Haa? You two were going to swap?” Killua yelled, a tick mark forming on his forehead.
“Well, we figured now that we both have the Mangekyou it was common sense…?” Shisui muttered, rubbing an arm.
“If you’d told us in the first place that’s why you wanted to kill her, then we could’ve told you,” Itachi scolded. No matter how old Killua was mentally, Itachi would never stop being an older brother, it seemed.
“Jeez… Well, in that case, let’s just swap them between the three of us. I’m not going blind because of your BS, y’know,” Killua muttered. “You guys were going to use that Madara guy to oversee the transfer, right?” The pair nodded.
“We’ll just have to do it the same way we did it with Shisui’s eyes now though. Madara can’t know you’ve also awakened your Mangekyou, Sasuke.” Itachi decided.
“Yeah, okay. Get someone who can do it quickly though, we don’t have much time.”

“Goodbye, Nii-san, Shisui.”

ROOT, and later ANBU found Uchiha Sasuke unconscious in a dirty street, surrounded by his eyeless, murdered kinsman.
Strangely enough, his eyes were puffy.
But those were probably a result of crying, no?