Naruto SI: Kaito Red Lightnin Chapter 227
Kushina smiled softly. "Well, since we have to stay here for at least the next hour, how about we eat lunch, ya know?"
She lifted the extra bento she'd brought. "I mean… I packed extra just in case, ya know."
Tsunade shrugged lightly.
Kaito, meanwhile, was still studying the readings on the tablet, rubbing his chin thoughtfully. "Ya know… I still haven't named the seal yet," he said without looking up. "How about we call it Uzumaki Woven Reconstruction Imprint Transformation Engine. 'U.W.R.I.T.E.' for short."
There was a pause.
Tsunade stared at him.
Kushina blinked once. Then she chuckled and reached over to pat Kaito lightly on the shoulder. "Oh, Kai-kun… I told you before. You're good at many things, but naming isn't one of them. You inherited your father's lousy naming sense."
Kaito immediately crossed his arms defensively "Hey, it's a good name. I think it has a nice ring to it." He turned to Kimimaro. "You think so too, right?"
Kimimaro nodded without hesitation. "Yes. It is a good name, Kaito-sama."
Kaito looked back at Kushina with a small, triumphant grin. "See? He agrees that it's a good name, ya know."
Tsunade rubbed her temple and exhaled slowly through her nose. "Why am I always surrounded by idiots?"
…
The treatment room was quiet again.
Tsunade stood beside the bed, tablet in hand, eyes scanning the flowing lines of data across the screen.
Kushina sat in the chair beside Kimimaro, holding a pack of dango. She hummed casually to herself, legs swinging lightly as she chewed on a skewer. Kaito had picked it up for her from the hospital cafeteria earlier.
Kimimaro sat upright on the bed, shirt back on, posture straight as always. If not for the faint black crest-shaped seal just below his collarbone, it would have looked as if nothing had happened at all.
Kaito stood off to the side, hunched over the desk in the room, scribbling frantically across a sheet of paper. The desk was littered with crumpled drafts scattered around him.
Suddenly—
He slammed the pen down dramatically against the desk.
All three of them turned toward him.
"I got it," Kaito declared.
Kushina let out a soft sigh, already shaking her head. "Oh, Kai-kun…"
Tsunade's thumb paused mid-scroll. She sighed without even looking up. "You're really not going to give up, are you?"
Kaito ignored her completely. A grin spread across his face like he had just solved a war strategy.
"We call it Cellular Override and Mutation Platform for Reprogramming Organisms via Manipulated Inherited Sequence Editing," he said proudly. "C.O.M.P.R.O.M.I.S.E. for short."
Silence.
Kaito's smile faltered just slightly. "…What do you guys think?"
Kimimaro nodded once without hesitation. "That is a good name, Kaito-sama."
Kushina slowly shook her head. "Kai-kun… you are really bad at naming things, ya know."
Kaito frowned immediately. "Oh, come on. What's wrong with this name now? It describes the function of the seal. And C.O.M.P.R.O.M.I.S.E. even has a nice ring to it, ya know."
Tsunade snorted lightly, still looking at the tablet. "Yeah. Really rolls off the tongue."
"Exactly," Kaito said, completely missing the sarcasm.
"Kai-kun," Kushina said patiently, tapping the dango stick lightly against the empty wrapper, "that's longer than the last one, ya know."
Tsunade finally lowered the tablet and gave him a long, unimpressed look.
"Kid, I'm not saying that entire thing during a medical briefing," she said flatly. "I'm not telling someone I'm about to use C.O.M.P.R.O.M.I.S.E. on them. Or that they've been C.O.M.P.R.O.M.I.S.E.d."
Kaito scoffed. "It's called wordplay, ya know. Try it sometime."
Kushina chuckled and reached over to pat his arm. "Why don't we call it something simple? Like 'Uzumaki Cellular Stabilization Seal,' ya know."
Tsunade nodded once. "Yeah. That's better."
Kaito threw his hands up in disbelief. "Oh, come on. How is that better than all the ones I gave? And how is that shorter? That's way longer than just calling it C.O.M.P.R.O.M.I.S.E."
"It's practical," Tsunade replied evenly. "Which is more than I can say for whatever you just said."
Kimimaro glanced at Kaito again. "I still think it is a good name."
Kushina smiled at him fondly. "You're too polite, Kimi-kun."
Tsunade set the tablet down on the table with a quiet tap, her tone shifting back to business. "Well, anyway. Everything is stable. There's no sign of rejection."
She looked directly at Kimimaro. "You can leave now. And remember—don't skip your checkups."
"I understand," Kimimaro replied calmly.
Kushina stood, gathering the empty bento boxes from the desk. "Come on. Let's let Tsuna-nee get back to her mountain of paperwork before she dumps it on you again, Kai-kun."
Tsunade smiled knowingly. "Don't tempt me."
Kaito narrowed his eyes slightly. 'Why is she smiling like that?'
They stepped out into the corridor together.
The hallway was calm, afternoon sunlight spilling in through the tall windows along the opposite wall, warming the polished floor.
Just as Kushina walked out with the empty bento in her hands, two familiar figures approached from down the hall.
Mikoto Uchiha walked with her usual composed grace, dark hair falling neatly down her back. Beside her walked Itachi, posture straight, expression calm and unreadable.
They slowed when they saw one another.
"Kushina," Mikoto greeted warmly. "It's been a while."
"Mikoto," Kushina replied with a bright smile. "It's been too long, ya know."
She stepped forward and pulled the older woman into a hug.
Mikoto returned it gently.
When they stepped back, Mikoto's eyes lingered on Kushina for a moment longer than usual. She blinked faintly. "…You look well," she said. "More radiant than before."
Kushina blinked, then let out a soft giggle. "Ara? Do I?" She grinned brightly.
Mikoto nodded slightly. "You do. Your complexion is brighter. You look younger."
Kushina waved a hand lightly. "Hehehe. It's a secret, ya know."
Itachi greeted her with a slight bow of his head. "It is good to see you again, Lady Kushina."
Kushina smiled warmly at him. "It's good to see you too, Itachi-kun. How have you both been, ya know?"
"We've been well," Mikoto replied. She paused, then added, "If I may ask, what are you doing here, Kushina?" There was mild curiosity in her tone.
Kushina patted Kimimaro lightly on the shoulder. "Oh, I just accompanied Kimimaro here to visit Tsuna-nee for his checkup, ya know."
Mikoto nodded. "I see."
A second later, the door opened again.
Kaito stepped out, still mid-sentence. "…I'm telling you, the acronym makes it memorable—"
Tsunade stepped out beside him.
She noticed Mikoto and Itachi and gave a short nod. "Good. You're right on time."
Mikoto and Itachi bowed slightly. "Hokage-sama."
Itachi then glanced toward Kaito and gave him a small nod.
Kaito returned it just as subtly.
Then he glanced at his mother. "Mom, you should head home first. I'll send a clone with you."
Before she could say anything, a second Kaito appeared beside him in a soft puff of smoke.
The clone stretched his arms lightly. "Leave it to me, boss."
Kushina blinked at them both. "Eh? Why? You're not coming?"
Kaito scratched the back of his head. "Eh, no. I'll stay and help Aunt Tsunade for a bit. I'll be back for dinner, ya know."
Kushina narrowed her eyes slightly at the original, studying him for a moment. "…Alright. But don't overwork yourself, ya know."
"I won't," Kaito reassured her.
"Alright." Kushina then turned to Mikoto and Itachi. "We'll talk later, Mikoto," she said gently.
Then she pulled Itachi into a light hug. "And good luck, Itachi-kun, ya know."
Itachi stiffened just slightly in surprise before returning the gesture respectfully. He stepped back and bowed. "Thank you, Lady Kushina."
Mikoto inclined her head as well.
With that, Kushina turned and walked down the corridor, Kimimaro at her side and the clone following alongside them.
Once they were out of sight, Tsunade gestured toward the room. "Well. Let's go."
Mikoto and Itachi stepped inside.
Kaito followed behind them and quietly closed the door.
…
Inside, the room felt quieter than before.
The playful atmosphere from earlier was gone.
Tsunade gestured toward the bed. "Please take a seat."
Itachi stepped forward and sat on the edge of the examination bed, posture straight, hands resting neatly on his thighs.
Mikoto took the chair beside him, folding her hands in her lap. She didn't fidget. She didn't speak. But her eyes never left her son.
Tsunade walked back to the table and picked up her tablet. With her other hand, she grabbed the thin metal bracelet resting beside it.
She stepped back toward Itachi and held it out.
"Put this on."
Itachi accepted it calmly and slid it over his wrist. The bracelet clicked into place with a faint pulse of chakra before stabilizing.
Kaito stood slightly to the side, arms folded, watching quietly.
Tsunade glanced down as readings began to populate across the screen.
"So," she said evenly, eyes still scanning, "how are you feeling?"
"I feel fine, Hokage-sama," Itachi answered, voice steady as always.
Tsunade hummed lightly. "That's what you said last time."
Her thumb moved across the screen, scrolling through layers of data.
The room remained silent except for the faint tapping against the glass.
After a few seconds, her brows furrowed.
She clicked her tongue. "…Your condition has worsened since your last visit," she said plainly.
Itachi nodded once. "I see."
Mikoto's fingers tightened slightly in her lap. It was subtle—but noticeable.
Tsunade looked up from the tablet, eyes narrowing slightly. "You've been pushing your body again, haven't you?"
Itachi didn't look away.
He simply nodded.
Mikoto let out a quiet breath and lowered her gaze. "…Itachi-kun."
"I told you not to strain yourself," Tsunade continued, her tone firm but controlled. She glanced back at the screen. "At least you've been taking the medication I prescribed. It's slowed the rate of deterioration."
She looked at him again. "It's a good thing I called you in today."
Mikoto leaned forward slightly, unable to keep the question in any longer. "Lady Tsunade… have you found a way to treat Itachi?"
There was hope in her voice. Carefully restrained—but there.
Tsunade nodded once. "Possibly."
Her gaze shifted briefly toward Kaito. "It wouldn't have been possible if that brat hadn't developed a new tool."
Kaito blinked. "Eh?"
Mikoto turned toward him immediately. "…You helped develop the method, Kaito-kun?"
Kaito scratched the back of his head. "Eh… I just made the seal. Aunt Tsunade handled all the medical parts, ya know."
Tsunade snorted lightly. "Don't downplay it, brat. Without Kaito, I wouldn't even have this option."
She leaned back slightly, folding one arm loosely across her chest. "His work is already pushing medical ninjutsu further than anything I've done in years."
Mikoto's eyes softened as she turned to Kaito. "Kaito-kun… thank you. You've always taken care of Itachi."
She bowed her head slightly—not formal, but sincere. "I'm grateful."
Kaito immediately looked uncomfortable. He chuckled awkwardly and rubbed the back of his head. "Ah—please don't do that, Lady Mikoto… Itachi's my friend, ya know. Of course I'd help."
Beside him, Itachi gave a small nod, a faint, gentle smile touching his lips.
Tsunade cleared her throat, drawing their attention back. "As I was saying, we do have a new method that might work. But it comes with risks."
Mikoto straightened immediately. "What kind of risks?"
Tsunade didn't soften her tone. "The current survival rate is around sixty-five percent."
The room went quiet.
After a moment, Mikoto asked quietly, "Please… explain."
Tsunade folded her arms. "As I've told you before, Itachi's condition is MPA. His body is essentially attacking itself. His immune system and chakra network treat his own cells as enemies."
She tapped the tablet. "It disrupts internal chakra circulation. Over time, it creates microfractures along the pathways. That's why he experiences extreme fatigue that doesn't match his actual output. His body is constantly fighting a war it can't win."
She paused briefly, then continued.
"This new method uses advanced gene rewriting. Essentially, we locate the parts of Itachi's DNA responsible for triggering the MPA response… and replace them with a compatible genetic template."
Kaito spoke up from the side. "So we rewrite the flaw in his body so it stops attacking him."
Tsunade nodded once. "Yes. In simple terms."
"But…" Kaito tilted his head slightly, thinking it through. "That won't repair the damaged pathways though. It only stops further degradation."
"That's where the injections come in." She walked to the table and picked up a sealed vial. Holding it up so they could see, she continued, "This compound accelerates cellular regeneration. Gradually, it will heal damaged chakra coils and the immune system."
Kaito raised an eyebrow slightly. "You made this using those cells I gave you?"
Tsunade glanced at him. "Yes."
Then she added dryly, "Why do you think I've been dumping half my workload on you the past few months? I needed time to test the method and refine the injections."
Kaito blinked once. "…You could've just said that, ya know."
Tsunade ignored him and turned back to Itachi. "This treatment is slow. It will take approximately one year for the seal to completely rewrite."
Her gaze hardened slightly.
"When I say do not strain yourself, I mean it. If you push your body during the rewrite period, the immune response could spike again. If that happens, I won't be able to help you."
Itachi nodded once. "Understood."
Tsunade's eyes narrowed slightly.
"You said that before."
She stepped closer, voice calm but firm.
"You will follow my instructions. If I find out you've been straining yourself again, I will personally put you into a medically induced coma until the rewrite is complete. Do I make myself clear, Itachi?"
There was no anger in her tone. Just authority.
Itachi held her gaze and nodded. "Yes, Hokage-sama. I understand."
Tsunade gave a single nod, satisfied.
She turned to Mikoto. "I expect you to make sure your son doesn't act reckless."
Mikoto inclined her head calmly. "I will."
Kaito casually added from the side, "I can always seal away his chakra if you want."
Itachi slowly turned his head and gave him a look.
Kaito smiled and raised both hands. "I'm just offering solutions, ya know."
Tsunade exhaled softly through her nose.
Then Kaito frowned slightly. "Wait. You're planning to use Mikoto-san as the template?"
Tsunade looked at him. "Yes. Why?"
Kaito tilted his head. "Why not use Sasuke? He should be more genetically identical to Itachi than Mikoto-san. I mean, look at them both. If we take away Itachi's tear troughs and make them the same age, they could pass as identical twins, ya know."
Tsunade paused.
Kaito continued, thoughtful rather than teasing now. "Plus, aren't siblings genetically more compatible? Around sixty percent compared to about fifty with a parent? Using Sasuke might reduce the rejection probability even further, ya know."
He folded his arms. "And won't using Mikoto-san's DNA skew hormonal balance?"
Tsunade blinked once. "…Skew hormonal balance?"
Kaito nodded. "Yeah. You know. Make Itachi more feminine."
Itachi's eyes twitched.
Mikoto looked genuinely worried. "…That can happen?"
Tsunade stepped forward and smacked the back of Kaito's head lightly. "Idiot."
Kaito rubbed the back of his head.
"That will not happen," Tsunade said flatly. "We are rewriting a specific genetic trigger. Not reconstructing his entire biological profile."
Kaito muttered, still rubbing his head, "But my point still stands. Sasuke would be a higher compatibility template. That reduces the failure rate."
Tsunade pinched the bridge of her nose.
She looked at Itachi.
Then at Mikoto.
"…He's right," she admitted after a moment. "Using Sasuke increases compatibility odds by approximately eight percent. He would only need to provide a chakra imprint and a minimal DNA sample."
Mikoto didn't hesitate long. "If it improves his chances… then use Sasuke."
Itachi remained silent, expression calm.
Kaito nodded once. "Alright. I'll go get him. I'll be back in a few minutes."
Before anyone could respond—
He vanished.
Tsunade stared at the empty space for a moment.
Then she rubbed her temple again. "That kid always gives me more work."
…
Afternoon light streamed in through the windows of the Academy classroom.
Iruka stood at the front, chalk in hand, writing neatly across the board.
"—and it was the Second Hokage, Tobirama Senju, who established many of the village's core institutions," he continued, underlining a date with emphasis. "The Academy itself was created by Tobirama-sama. Every one of you sitting here is part of that legacy. The Academy exists so that—"
He paused mid-sentence.
A few students nodded along seriously.
A few pretended to.
In the back row, Naruto was asleep.
Head down. Mouth slightly open.
A small string of drool slowly spreading across his desk.
Iruka's eye twitched. "…Naruto."
No response.
The classroom grew noticeably quieter.
Shikamaru, who himself looked half-asleep, reached over and nudged him lazily. "Hey, man. Naruto. Wake up."
Naruto only mumbled, "Five more minutes…"
Iruka closed his eyes briefly, inhaled once, then reached for the wooden duster resting on the board's ledge.
He didn't throw it hard.
Just enough to get attention.
The duster flew across the room—
Just as it reached Naruto—
At the exact same moment—
Kaito appeared directly on top of Naruto's desk in a crouch.
The duster smacked straight into his face.
There was a loud thwack.
Kaito lost his balance instantly.
He tumbled backward—
And fell directly onto Naruto.
The classroom exploded into noise.
Naruto jolted awake. "What the— hey! What was that for?!"
Kaito stood up quickly, rubbing his face. He shot Iruka a glare. "Hey. Why did you throw that at me?"
Naruto pushed himself up, startled awake rubbing the back of his head. "…Nii-san?"
Kaito glanced down and nodded. "Hey, Naruto."
Iruka went pale. "I—I didn't throw it at you!" he blurted, rushing forward in a panic. "I was aiming for Naruto! I mean—not like that—I mean—he was sleeping in class and—"
He stiffly bowed. "Please accept my apologies, Kaito-san!"
Kaito waved a hand dismissively. "It's fine, Iruka-san. it didn't hurt."
Naruto blinked up at him, still half-confused. "What are you doing here, nii-san?"
The rest of the class stared openly.
Kaito dusted off his clothes. "Right. I'm here for Sasuke."
At the mention of his name, Sasuke's raised an eyebrow slightly.
Kaito turned casually toward him. "Come on."
Iruka blinked. "Excuse me?"
He stepped in front of Kaito instinctively. "Eh—wait. I can't just let you take a student without parental permission," he said carefully. "What's this about?"
Kaito tilted his head. "Huh? The Hokage asked me to bring him. His mother and brother are already there."
He added casually, "You can confirm it later if you want."
Iruka frowned slightly, clearly weighing the situation.
Behind him, Sasuke stood up without waiting. He picked up his bag.
Iruka glanced between them. "…Alright. But bring him back."
Kaito gave a casual shrug. "Not sure how long this might take, so I can't make any promises."
Naruto shot up halfway out of his seat.
"Oi! Where are you guys going? Take me with you, ya know!"
Kaito glanced at him. "Sorry, Naruto. I can't. I have work to do."
Naruto shoulder slumped. "What…"
Kaito stepped over to Sasuke and placed a hand lightly on his shoulder. "I'll just borrow him." And then—They vanished.
Iruka stared at the empty space where they had stood.
Naruto crossed his arms and grumbled loudly, "Oh, come on. He could've at least taken me with him, ya know. Why does Sasuke get to skip out while I'm stuck in Iruka-sensei's boring history class?"
Iruka slowly turned toward him. "Sit down, Naruto."
Naruto slumped back into his seat with a huff. "…This is so unfair, ya know."
…
Kaito reappeared in the treatment room exactly where he had been standing before.
Sasuke appeared with him and immediately stumbled forward. He fell face-first onto the floor with a dull thud.
There was a brief, heavy silence.
Kaito scratched the back of his head. "…Right. Sorry about that. First time using Hiraishin can be disorienting, ya know."
Sasuke pushed himself up slowly, clearly annoyed. "You could've warned me."
Mikoto stood quickly and helped him to his feet. "Sasuke-kun."
"I'm fine," Sasuke muttered, brushing off his clothes.
He adjusted his collar, then finally looked around the room properly.
His eyes moved from Tsunade… to Kaito… to Itachi.
"…What's going on?"
Tsunade was already at the desk, reviewing data on her tablet. She glanced back at them briefly.
"Well," she said evenly, "alright. Let's just get this over with."
She pointed toward the scroll laid open on the table.
"You. Put your hand there. Channel chakra into the seal."
Sasuke frowned slightly. "Why?"
Mikoto answered before Tsunade did.
"It's for your brother's treatment."
Sasuke's expression shifted instantly.
He didn't ask anything else.
He stepped forward and placed his hand over the seal matrix inscribed on the scroll.
A faint glow appeared as he began channeling chakra into it.
Tsunade stepped closer. "Give me your hand, kid."
Sasuke did without hesitation.
She made a small, precise cut on his fingertip. blood formed on the finger tip and Tsunade pressed it onto the center of the seal.
The markings pulsed once, absorbing it.
Then she immediately healed the cut with medical chakra.
Sasuke flexed his fingers slightly. "…That's it?"
"Yes," Tsunade replied.
Kaito walked over. "You already got Itachi's sample?"
Tsunade nodded. "We did it while you were away."
She then turned toward Mikoto, Itachi, and Sasuke. "It will take a while. I need to remap and align the template properly."
She gestured toward the door. "Why don't you come back in about an hour."
Mikoto looked at Itachi.
He gave a small nod.
"We'll wait outside," Mikoto said.
Sasuke glanced at his brother once more before following their mother out.
The door closed quietly.
The room grew still.
Kaito rolled his shoulders once. "Let me help."
Before Tsunade could respond, he formed a hand seal.
Two shadow clones appeared beside him in soft puffs of smoke.
One of the clones stretched lightly. "Alright. What section am I taking?"
Kaito pulled out a scroll and unsealed three more tablets onto the desk.
Tsunade looked at the tablets… then at him. "How?"
Kaito answered calmly. "I can make collaboration possible. We split the genome map into sections, work simultaneously, then merge the edits."
Tsunade considered it for half a second.
Then she nodded. "Alright."
She divided the layout, assigning each of them a section she had already highlighted. Itachi's sections were colored red. Sasuke's were purple to differentiate them. The damaged portions were marked white so they stood out clearly and were easier to replace.
It was basically drag and drop.
Just a lot of dragging and dropping.
Kaito and his clones each took a tablet after syncing the project. They moved apart slightly and began working on their assigned sections separately.
While Tsunade and one clone focused on remapping and alignment, the original Kaito was doing something else.
'This is the perfect opportunity to give Itachi the EMS.'
He had already thought it through beforehand.
The idea was simple in theory — rewrite Itachi's ocular structure into Sasuke's template, similar to how Kawaki received Isshiki's eyes. If Itachi or Tsunade ever asked why his eyes evolved, he could just say it was a side effect of the treatment merging Sasuke's DNA with Itachi's.
But for that to work, Sasuke needed the Mangekyō first.
That part was easy.
By carefully comparing both sets of eyes, Kaito could identify the specific evolution markers responsible for triggering the awakening. All he had to do was copy those markers into Sasuke's genetic pattern.
No emotional trauma required.
Just a precise adjustment.
'Once that's done… when Itachi's eyes are fully rewritten into Sasuke's template…'
His fingers moved steadily across the screen.
'It'll automatically be MS.'
He didn't say a word out loud.
'And when the seal activates and completes the rewrite… Itachi's chakra will resonate with Sasuke's eyes. That resonance will awaken EMS naturally. No transplant needed.'
He continued working without changing his expression.
'And with the Zetsu-cell treatment he'll be receiving over the year… he might even have a chance at awakening the Rinnegan.'
He had already discussed it with Minato beforehand.
Minato had agreed.
Because Kaito had written the entire program himself, he could ensure the additional modifications inside Itachi's ocular rewrite were hidden. They wouldn't appear in the general overview Tsunade was monitoring.
After around thirty minutes of quiet work, Kaito stood up and walked over to Tsunade.
"I'm done."
Tsunade glanced at him. "Already?"
Kaito didn't answer.
He simply connected his tablet to hers and merged the sections he had completed. A moment later, his clones stepped over and synced their finished portions as well.
The data integrated smoothly.
Tsunade scanned the merged result carefully.
All the while, Kaito stood there with a faint, pleased smile on his face.
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