The function of Kotoamatsukami in canon is left incredibly vague, except that it apparently works really subtlely, and yet it can also make Itachi change teams in the blink of an eye. Not easy to work with, but I've done some headcanonning. Be lenient on me, kay?
The Kage Civil War#2
Aaight, look. My Mangekyo power is absolutely busted.
I'm...not actually sure why I'm writing this down. It's gonna cause some serious issues if anyone actually reads it, and I may just burn this when I'm finished, but I need to get my thoughts in order. Cos frankly, I'm scared of what it lets me do.
I call it Kotoamatsukami. That's, uh, a religious thing. Apparently Itachi's actually taken after me when it comes to that naming schema, which is kinda funny. But, yeah.
It lets me mind control people.
Okay, okay, that's an oversimplification. But basically it turns my target's brain into an all-you-can-abuse buffet.
Kotoamatsukami never actually forces the target to do anything against their own will, it's only effects concern with memory.
It rewrites it completely; changing memories, hiding them, adding new ones. And by reframing the context of the present, it can cause a person to act completely differently. They might believe that they were actually always working with a different side, that they've always hated or loved a certain someone, hell, it can completely rewrite all their experiences since birth if you're thorough enough.
The obvious downside is that if what you've made them remember conflicts with the reality they perceive, they'll get confused and may begin to suspect. You can't just brainwash the Hokage into believing they've always been your servant, obviously, because if they start acting differently then their teammates or friends might notice and try to take them down. And if their new memories don't make them like you enough, they could quite possibly betray you of their own will and there'd be nothing you can do about it.
But even that can be overcome with a sufficiently skilful use. Organising their thoughts so that they'll think other people around them are lying to them, or misinformed. Making the target think that they're part of some elaborate deceptive scheme. That sort of tricky nonsense. If you have a long enough period of eye contact while you're applying the jutsu, you can even set it up so that different stimuli trigger different memories appearing or disappearing. You can even completely invalidate other genjutsu or fuuninjutsu that are giving the target commands, with a memory as simple as making them think that 'attack the leaf ninja' actually means 'do the exact opposite thing'.
The technique is almost impossible to dismantle from the outside, at least not without permanently brain damaging the afflicted, but the target themselves can remove the jutsu with only a little more effort than a standard 'dispel' casting, if they're a sensory type or become aware of it in some other way. This would be a weakness, except that the caster has a whole host of ways to make the target not want to do that. Simply making them think people are lying to them about them being affected, or more insidiously, that they chose to be affected by the genjutsu of their own free will for some other reason. Again, the only limits here are the imagination of the caster and how long they have to cast it. A brief moment of eye contact in the middle of combat will net you a total memory overwrite, but you won't be able to set up much for the future. But if you're sat in front of them for a few minutes to an hour, then there's practically no limit to what you can do to a person.
(or spend a long time in advance preparing a general command to be aimed at anyone like, I don't know, a supercomplicated set of 'If X then Y' commands to make them protect Konoha at all costs.)
The only weaknesses that I know of are twofold. One, it's monstrously high chakra cost. I used this once and I was out of action for days. And two, it's ridiculous cooldown time. If I hit someone with the Kotoamatsukami now, I wouldn't be able to use it again for another nine, ten years.
That's actually a bit of a relief, to be honest. If someone could use Kotoamatsukami every week, hell, every six months...well, it's quite possible they could have taken over the whole ninja world without us ever knowing about it.
-Hidden page in Shisui Uchiha's private notebook. Sewn into the lining of Itachi Uchiha's forehead protector.
Hinata Hyuuga had been born a lonely girl. Pressured by her parents, ignored by her cousins, she had grown up with few friends and fewer confidants. Then had come the Hyuuga massacre. When everything in her world had changed. It was in the aftermath of that horrific experience that she had met Shimura Danzo.
He had given her someone she could trust. He had given her purpose. He had been her only real anchor in the world when she had felt so lost and afraid, even when everyone else in the world had seemed cruel, and stupid, and ignorant.
She had loved him like a father.
Of course, the world hadn't known. She had been assigned to team seven alongside Naruto and Sasuke, all by design of course. Her mission had been to assess the progress of the Kyuubi Jinchurikki, to ensure he would remain in control, as well as the youngest Uchiha heir and his progress.
Above all else, her duty had been to grow stronger. Strong enough to confront Neji Hyuuga, the man who had disobeyed his orders and his village, and to hunt him down and kill him. For justice, and for her own revenge. To that end, she had joined and spied on Orochimaru, and then killed him when he was no longer of use. She had torn through Deidara, and eventually, she had brought Neji down.
And now she was at the culmination of all her master's planning. Where all the villages would be brought together under Konoha's control, and all the agents who opposed him would be snuffed out all at once.
"Master. I take it you want him dead?" She asked, not taking her eyes off her teammate. She noticed with some small annoyance that she still considered Naruto her teammate. Did it not work...no, of course it worked. Any weakness is mine alonw.
"Not dead." Danzo corrected her. "The nine-tails running rampant would be the last thing we need right now. Suppress him."
Naruto looked between them, confusion plain on his face. "Uh, Hinata, is this some plan I'm supposed to be in on-"
"Of course, master." She replied, and began walking forwards.
"Oh, fucknuckles." Naruto grimaced. "Uh, Hinata? Wrong target?"
"No, I'm good." She kept walking.
"Hinata, that's-" His face lit up. "Hinata! You're under a genjutsu! You can tell I'm telling the truth, right? Check, you can just get rid of it with your Hiragekothingy!"
He definitely was telling the truth, and she saw it. She smiled at him. "I know."
"Whu-"
She punched him in the stomach. He went flying backwards, landing on his feet several metres backwards. Then he narrowed his eyes, and stood straight, spreading his arms to either side.
"Really." She narrowed her eyes at him. "That's your game?" She didn't stop walking towards him. "Fight back, Naruto, I will 64-palms you while you're stood there."
"Hey, eye-stealer!" Naruto called over her shoulder. "If I kill you, that'll make the genjutsu turn off, right?"
"No." Danzo said, not changing expression.
Naruto turned back to Hinata. "Is he lying?"
"No." She replied, even though he was.
He looked at her expression for a moment, then grinned. "He totally is, isn't he? I've known you long enough to tell when you're badly lying."
Hinata bared her teeth. She cleared the last two metres between them at top speed and readied herself in front of him. Still, he didn't move from his pose, so she let her attack fly, the eight trigrams sixty-four palms peppering most of the chakra points in his body. He collapsed backwards to the floor.
"Did you really think I wouldn't be able to bring myself to do that? Were you planning for me to dramatically stop just before hitting you?" She asked, looking down at him. She'd left his head mostly intact, so he could reply.
"What?" Naruto snorted. "Nah. I was just buying time so I could gather sage chakra."
Oh shit-
There was a flash, and that ridiculous orange eyeliner appeared, and then Naruto booted her in the chest so hard she flew all the way across the bridge.
"Ungrateful little bastard!" Mei shouted at Haku, firing another blast of lava style at the table he was hiding behind. He took a second to conclude that, yeah, those were all technically true points to make, before standing up and kicking the table towards her.
"A little hypocritical, don't you think?" He shot back, summoning a pair of ice clones and charging forwards with them. "Seriously, don't you have enough combination nature transformations?"
He fired a hailstorm of ice senbon, but Mei conjured up a wall of vapour style...vapour, I guess? The senbon melted the moment they entered it.
"Buffeting wind!" Haku shouted, taking a page out of Naruto's book, but even though the vapour washed over Mei, it had no visible effect on her. A resistance then, since he'd seen her melt someone alive with that once. Water and fire. Boil release. It's nasty stuff.
Coming right back at him was another globule of lava, which was only heated further by the wind he was launching at her (fucking elemental supereffects-) and he quickly manifested an ice mirror in front of himself. The lava shook the mirror, hard, but it wasn't enough to melt it.
Good to know. That means...
His two ice clones jumped in at Mei from above on either side, both putting one hand up and shouting "Demonic ice-"
"Vapour dragon!" Mei countered. The discoloured mist around her formed itself into a large, well, dragon, sweeping around and above her and catching both Haku clones in its jaws. Both were carried into a wall, and shattered.
"Two-timing little git." Mei snarled, putting her hands up and reapplying the cloud of vapour surrounding her. "Is this why you accepted my invitation in the first place? To join Mist and overthrow me?"
Haku shrugged, grinning. "Yeah, basically."
The vapour melts me if I'm in it. She can make it into a deadly attack jutsu if it's up. She can't melt through my ice mirrors, so if I can catch her in the prison she's dead, but to do that I have to get close...This is gonna be interesting.
"I'm going to flay you." Mei snarled. "Lava bullet!"
"Ice spear!"
"Fuck this matchup!" Sasuke shouted out loud, catching a punch from the Raikage on Raito's blade and sliding backwards, then jumping upwards as a fucking laser beam from the Tsuchikage nearly tore him apart, and then he was lucky Gaara's sand came in to pull him away from A's followup flying knee.
Hey, what people would be the worst opponents for Gaara? Well, someone fast enough to get through his sand walls, or someone who's ability could blast through them like they weren't even there.
Oh, would you look at that?
Hey, what people would be the worst opponents for Sasuke? Well, someone fast enough to dodge his hax abilities, or someone who could fly almost entirely out of range of his melee attacks.
OH, WOULD YOU LOOK AT THAT?
"We need to re-strategise." Gaara told him. The Kazekage was short of breath; this was likely the most running around he'd done in a while.
"Yeah, you think?" Sasuke shot back. "Get us some cover!" He shot a fireball at Onoki to distract him, and Gaara pulled up a dome of sand around them. There was a thud, as one of the Kazekage's fists crashed into it.
"I'll hold off Captain Falcon," Sasuke instructed, "you try to keep Santa Claus moving with your sand!"
"That status quo is bad for us." Gaara reminded him.
"I know, but if you keep standing still then they'll move to change it. When I say switch, be ready to focus on bogging down A."
"Alright. I trust you."
"Mark?"
"Sync."
"Aaight. Open us up!" The sand shield exploded outwards, just in time for the Raikage to come charging in. The attack had been meant to hit the sand wall, and when his preferred target vanished from in front of him A was left off-balance, giving Sasuke time to summon a sword from his bracer and swing it.
Shibuki's explosive tags weren't able to pierce the Raikage's lightning chakra mode cloak, but it sure sent him flying across the room. Sasuke didn't waste any time sprinting straight for him, sheathing shibuki and and drawing Raito, the sword's two halves paired together.
"Oh? You're approaching me?" The Raikage taunted. "Instead of running away, you're coming right to me?"
"I can't beat the shit out of you without getting closer." Sasuke told him, grinning.
"Oh ho! Then come as close as you like!" A wound up, and punched.
"Chidori!" Sasuke replied, channelling electricity through one blade and stabbing. Fist met sword in a collision of purple energy, sending a shockwave out around them, but A didn't hesitate to launch the next attack, and the next, forcing Sasuke to dodge, duck, and swing his blades like his life depended on it. Because it literally did. One punch would take his head off.
He was slower than the Raikage, but his hand-speed was almost comparable. And the Sharingan was busted, meaning his boosted reaction time let him keep up. And most importantly...
"Why aren't your swords breaking?" A growled at him, annoyed.
"Raito is imbued with lightning chakra." Sasuke smirked at him. "It can eat up your attacks like they're breakfast."
"How does that work?"
"Fuck if I know."
The Raikage scowled, and punched harder.
Around them, the hall was gradually falling apart. Onoki was flying around like a mosquito, being pursued by tendrils of sand from all directions trying desperately to snatch him out of the air. It wasn't working. He was fast in the air, and since Gaara had imbued wind chakra into the sand to make it lighter, it was easier to punch out of. After a while, Onoki seemed to think he'd got the hang of the sand's movement, spinning through a particularly tight gap and coming to a stop in the air, pointing both arms at Gaara. "Particle Style!" He shouted. "Special Beam Cannon!"
Sasuke saw it in his peripheral vision, and narrowed his eyes. "SWITCH!"
Sasuke, showing an incredible amount of trust in his teammate, disengaged entirely and turned his back to a rampant Kage. Gaara, showing an incredible amount of trust in his teammate, left himself completely open to Onoki's death laser and focused fully on A.
The Raikage charged for Sasuke's back, but found himself grappled from all sides by sand, and by the time he could free himself of it, the Uchiha was already out of reach, leaping up to Onoki with lightning trailing from his fist. He didn't want to kill important international figures, hence no rasenkunai, but he had no problem with stunning them so bad they fell out of the sky.
The aforementioned Tsuchikage saw Sasuke approaching, and his eyes widened. He aborted whatever jutsu he'd been charging at Gaara, instead reaching one arm out past Sasuke. "Particle Style, lightweight boulder jutsu!"
There was a flash.
The Sharingan was the only reason Sasuke reacted fast enough, and his paranoia in immediately resorting to the Susanno was the only reason he survived.
One moment the Raikage was on the floor, the next he was driving an elbow into Sasuke's back, the purple ribcage forming around him cracking under the assault but barely slowing the strike down enough to render it non-crippling. Sasuke was thrown forwards so hard he bounced off a wall, and Gaara had to catch him in a pillow of sand to stop him crashing into the floor full force.
Instead, he merely collapsed to his knees, groaning. "Ooooow...What in the six paths of bullshit was that?"
"The Tsuchikage's particle style lets him decrease the mass of an object or ninja without affecting their chakra or muscle power." Gaara told him, reaching down with a hand and pulling him to his feet. "It allows him to increase someone's speed by incredible amounts, or decrease the momentum behind an incoming attack."
"And he also gets lasers that disintegrate everything?" Sasuke stood up and pointed at the Tsuchikage. "I know this is kinda rich coming from me, but your powers are bullshit."
"Noted." Onoki chuckled, hovering above the floor, next to a Raikage who was literally glowing white and purple all at once. "Well then, would you like to go for round two?"
"Hurry up, Naruto. Hinata." Sasuke muttered to himself, reaching up with one hand to clean off the blood dripping from his eyes. If this goes on any longer, I might not be coming out of it with two working eyes.
Hinata flew back, going over Danzo's head, and watched with the Byakugan as Naruto completely ignored her, getting to his feet and charging for her master.
His chakra points are completely blocked up, but it doesn't matter, he's running entirely on senjutsu. I can't even see it, nevermind interfere with it. Smart. Kesshotoketsu!
Crystals erupted around Naruto, trapping him in place, and though he was able to tear his way out of them in a brief moment, it was enough time for Hinata to land and charge back in towards him, throwing a palm strike at his forehead.
He blocked it.
"It's really nice to be able to actually do that, you know? Block you?" He sighed, dreamily.
She glared. "Lionfists!" Her next punch sent him sliding back a few steps, and she followed it up with a vacuum palm that he kicked up a block of stone to intercept, and then she was leaping in through the rubble with a flurry of rapid fire punches that he set about countering.
"So how does his thing work, huh?" He shouted at her, mid-combination. "False memories? Subtle control? You wouldn't be acting like this if he'd completely taken you over, so what's the deal?"
"The deal," She shot back, "is that I've been working for him for years!"
"Uh, when?" He pointed out. "You were our teammate for six months?"
"It's called being a spy! I was reporting to him the whole time!"
"Again, when? You spent all your free time watching me!"
"Do you want me to draw you a fucking timetable or can I get back to beating you senseless?" Naruto wasn't lying. She had spent a lot of time watching him. What did he think Danzo's Kotoamatsukami had been about?
And annoyingly, she wasn't beating him senseless. He flipped himself upside down and went for a spinning double kick that almost knocked her off the bridge, then landed on his hands (facing away from her) and continued to try and kick the crap out of her, blocking all her attacks perfectly without even being able to see.
It's the sage mode. He's got a better sense of his surroundings than me. And he's faster than me. Oh that's just plain not fair.
"He can't have made you forget what you did with us!" Naruto shouted. "Not when he knows you know I'm being honest about every memory I describe! And that means-" He pushed himself off of his hands, both feet kicking her backwards as he moved into a midair spin, energy gathering in his hands. "-That there's no way you don't still care! Senjutsu; Rasenshuriken!"
The spinning white sphere, blades of chakra making a hideous mechanical whining noise, came barrelling through the air towards her.
She put her hands out. "Hira-" No, she couldn't disrupt it, it wasn't normal chakra, "Substi-" and her eyes widened, as she realised that Danzo was directly behind her. Chakra exhausted, too, after using his technique. She couldn't dodge, or her master would die.
"Heavenly spin!" She eventually decided, and the dome of chakra blossomed around her, but the rasenshuriken was taking no prisoners.
Sparks of chakra flew as it tore into her defence, forcing her entire dome to either slide backwards rapidly or be penetrated entirely.
"That's why you're so angry!" Naruto shouted, pointing an accusing finger at her. "Because you're hurting! Because you're trying not to think about what he's asking you to do! Remember the night we got back from Wave? Remember the night you left? Look me in the eyes and tell me you remember those times, and you're still going to betray me!"
"SHUT UP!" She screamed.
She cut her jutsu, letting the rasenshuriken fly freely towards her. This better work. "Crystal release! Heavenly spin!"
The dome that span out from her then wasn't the light blue chakra that she usually employed. Instead, at the price of the numbness of the Gokei spreading further up her legs and arms, her defence was constructed of millions of tiny crystal shards, overlapping, growing, and spinning around her. The Rasenshuriken smashed into it, and it held, the two techniques spinning against each other like-
Yeah, look, it was like beyblades, alright, it was a freaking Kage-level beyblade battle.
The rasenshuriken began to lose momentum.
Naruto 'tch'd, and slapped his hands to the ground. "Sage art, swamp of the underworld!"
The surface of the bridge rippled, and Danzo was quick to jump backwards as a large zone in front of Naruto began to sink.
The entire structure sagged as Hinata's dome span itself down into a muddy, swampy mess.
Hinata cut the technique but it was too late, by the time she dropped the wall of crystal around her she was already submerged deep into the muck, and it flowed in to bury her almost to the head.
Naruto sprinted across the surface of the mud with ease, passing her in a flash. "Lucky for you, I don't plan on making you suffer any more!" He shot at her, before building up a base Rasengan in his palm and rocketing towards Danzo.
No. No, no, you stay AWAY FROM HIM!
White rippled across her body.
Naruto was less than a foot from Danzo's face before Hinata appeared behind him, Ivory feet gripping perfectly to the swamp beneath her, and hooked one arm around his and threw him back the other way.
He slammed down into the swamp he'd created, sinking halfway into the muck.
"You're right." Hinata admitted, meeting his eyes. "Of course I care about you. How could I not? Nothing you remember is untrue; every moment we were together I was there, I saw it, I felt it. I told you I loved you and I meant it. And it's made me weaker." She pointed to her own forehead, where her Byakugan highlighted the foreign chakra pulsing through her mind. "I know the genjutsu's there. Because I asked for it. I warned master Danzo that I might not have the strength to hurt my team. And he told me to join up with you, go through with your plan, and wait."
Naruto pulled himself out of the swamp and looked at her warily, as she continued.
Cracks split through her arms, and with a yank, each limb split into two. In full general grievous style, each of the four arms moved independently, and readied into stance. "That's what this Kotoamatsukami is. It's my final gift from him. He put it there so that I can bring myself to destroy you."
"LET ME GO!"
"NO! Stay down Kudos!"
"I have to go! I have to save her!"
Kudos strained and strained, as Forsooth and a handful of other owls all piled on top of him to keep him in place.
"Kudos, please!" Forsooth begged, forcibly holding his wing closed. "You are in no condition to go anywhere! It's that eye, Neji did something to you, please stay still while we bring in your grandmother-"
"NO!" Kudos wailed, crying. "I have to save her! Please, believe me, mistress Hinata is in danger, I'm the only one that can free her let me GO!"
The other owls didn't listen, and continued to hold him down, and Kudos continued to stare wildly into space.
The eye in his left socket continued to glow the blood red of a Mangekyo Sharingan.
To be continued...
Y'all ever write two chapters worth of stuff and then go 'wait, stop, just, publish the first bit'? The battles rage on, and Naruto has the unenviable job of trying to fight his friend.
To reiterate, the Kotoamatsukami Danzo used on Hinata is making her think that she's always been secretly reporting to him. It hasn't taken anything away, otherwise Naruto would be able to tell her and she would realise she was being manipulated. And she thinks that the genjutsu currently in her head is keeping her able to hurt Naruto, and she won't remove it because she's afraid that she'll be too emotional about Naruto to finish her mission without it. 'Of course, in my head I would still do it, but what if my heart takes over my head'?
Danzo making 4000 IQ plays.
Next time, the chaos continues. Who will survive? Spoiler alert; certainly not the arenas they're fighting in...
