Back in Konoha, Kakashi sat alone in the dim light of his basement lab.
The walls were lined with scrolls, sealed vials, and notes scattered across every table. Strange symbols glowed softly on the walls, sealing marks he'd created himself, made with the Formula Reconstruction Technique. The air smelled of ink, herbs, and faint chemicals. He hadn't stepped outside in weeks.
.
This was no ordinary research. This was the future of his body… and maybe even the future of bloodline mastery.
He flipped through Kabuto's scrolls again. The medical codes, cell regeneration formulas, and chakra flow diagrams, were perfect in theory but dangerous in execution. The old Chimera Technique required living sacrifices. Kakashi refused to allow that.
"Devour… and synthesize, no wonder he could synthesize animals together," he murmured, narrowing his eyes.
But that was the key. Not just absorbing another bloodline. It had to be perfect integration. No rejection, no chakra imbalance, no mutation. Each new gene had to blend into his own like it always belonged there.
He used his right hand to focus the chakra into the crystalized vial in front of him. Inside was a sample of Katsuyus's healing enzyme, harvested from Katsuyu's clone cells with Tsunade's help. It wasn't exactly Senju DNA, but it was the closest safe source with huge vitality. He'd get there in small steps.
He set the sample aside. It wasn't ready yet.
Kakashi turned to a stack of genetic models he'd built. Each paper strand showed gene sequences of known bloodlines, Uchiha, Senju, Uzumaki, and even samples taken from the remnants of the Kaguya clan, found in Kabuto's scrolls.
He took a deep breath. His chakra was a strong High Kage level, and still rising thanks to the absorbed Nine-Tails energy that he still had inside him. But adding new genes would demand even more. He'd need to train his body to keep up..
Kakashi picked up a scroll labeled 'Synthesis Base Model Ver. 4.'
He opened it carefully. This version used the Formula Reconstruction Technique to build a chakra matrix seal that could identify, devour, and replace inactive or weak genes.
The devoured genes wouldn't just merge they'd be restructured, made stronger, and amplified by his chakra. This was the closest he'd gotten to perfection.
But he needed one more step.
He focused, letting his chakra flow through his fingers and into the seal drawn on the testing table. The chakra flickered, then lit up with a soft blue-green hue.
A clear sign that the formula was working. The devour-and-rebuild method was stable in theory, but he still had to test it with actual genetic material.
He retrieved a small preserved vial, snake tissue from Garaga's offspring, a failed summon that had died in infancy but carried Garaga's strong bloodline. He placed a droplet into the chakra circle.
The moment the enzyme touched the circle, the seal pulsed violently. Chakra lines danced along the formula, and the tissue dissolved into light.
A second later, Kakashi felt it. The formula had copied and absorbed the traits, heat sensing, and rapid reflex enhancement. It was only temporary, but it proved the concept.
"It worked," he whispered.
But that wasn't enough.
He opened a blank scroll and began writing new formula lines. These ones would not just absorb, this seal would store the bloodline traits in layers within his chakra system.
The base design allowed him to activate or suppress specific traits at will, preventing chakra overload or personality corruption, like what had happened to others who tried forbidden techniques.
Days passed.
Tsunade came to check on him once, bringing food. Kurenai and Anko waited upstairs. They never questioned his work. They just asked if he was eating and resting. He lied, of course. He hadn't slept in two days.
His notes grew longer. The new version of the Chimera Technique was forming right in front of him.
Version 7-Devour-Type: Internal Synthesis Model
Target genetic sample, Decode DNA pattern via chakra imprint. Strip dangerous or unstable traits. Synthesize compatible bloodline sequences into the host's DNA Chakra reinforcement layer, increase chakra capacity post-integration
He looked at the scroll. This one didn't need anyone else's body. No stealing organs. No forced implants. It was elegant, clean, and precise. It used chakra as the medium of change.
He tested it again, this time using an old hair strand from a Hyuuga that he'd kept from a training accident some months ago. The Byakugan gene.
When he activated the seal, the hair strand glowed… then disintegrated.
But something happened. His eyes twitched for a moment. For five seconds, he saw chakra flow through the wall. It faded quickly, but it meant the bloodline trait had entered him, even for a short time.
"Almost," he muttered.
He recorded the feedback. The issue was chakra conflict. His own chakra signature was strong, part Uchiha (through Obito's Sharingan), part Senju, part Nine-Tails chakra. Adding more required buffering.
So he adjusted the formula again. This time, he added a second layer: a stabilizer seal. This one was inspired by the Lotus Seal he created for Sakura and Karin. It used the yang chakra and healing enzymes to balance the body's energy flow during synthesis.
This took another two days to perfect. Every attempt left him drained.
But he smiled every time it worked better than before.
On the seventh day, Kakashi leaned back in his chair. His eyes were bloodshot. His chakra was low. But the scroll in front of him, written with precise lines of ink, sealed with chakra, and marked with his own blood, was complete.
Chimera Technique: Synthesis Core Seal, Final Prototype
It used Kabuto's cell regeneration model, merged with Katsuyu's healing enzymes, and built upon the foundation of the devour-type formula. It didn't steal, it devoured and adapted. And it offered something new.
Every time a new bloodline was devoured and successfully synthesized, the chakra capacity of the user would grow, not just in quantity, but in quality. The body would evolve with each integration. With safety limits.
It was no longer similar to Hiruko's monstrosity. This was something else.
A safe, self-enhancing bloodline fusion technique that honored every drop of power it absorbed.
Kakashi stared at it for a long time.
He heard footsteps above. Tsunade's voice.
"Kakashi? You're still in there?"
"Yes. I'm done." He looked up and smiled faintly.
He rolled up the scroll, sealing it into a chakra-proof case. He would test it tomorrow, on more powerful genes of Katsuyu's. If it worked, his healing factor would increase drastically. That would be the first real gain.
For now, he let his chakra settle and stood up.
When he walked up the stairs, the evening sun hit his face for the first time in days. Anko sat at the table, feet up. Kurenai looked relieved. Tsunade's eyes softened when she saw him.
"You look like hell," she muttered.
"I feel like it," Kakashi said, chuckling.
But his hand tightened around the sealed scroll.
He had done it.