The basement beneath Kakashi's home now was a blend of Konoha technology and personal innovation. Steel shelves lined the walls, filled with scrolls, vials, preserved tissues in suspension, chakra-detection tools, and half-finished seal matrices.
In the center was a wide metal table, covered with open documents written what was retrieved from Kabuto's storage sealing tag, medical blueprints, experimental data, and pages filled with Orochimaru's old transplant notes.
He was fortunate that Kabuto had a storage sealing tag wrapped under his wrist, where he had found all of Kabuto's personal belongings and also some of Orochimaru's scrolls that were given to Kabuto.
As Kakashi stood over the table, his sleeves rolled up, his Sharingan sealed like always, and his eyes focused sharply as he skimmed through the cellular regeneration diagrams Kabuto had mastered.
Charts of mitotic cell division, notes on accelerated healing, and chakra-based gene stabilizers were spread before him. Many of the symbols were twisted, and complex, but not beyond him. With his talent and expanded chakra control, he could understand it. And he wanted to.
Behind him, Tsunade sat on a stool, her blonde hair tied up as she wore her lab coat. She was holding a preserved sample of Kabuto's modified skin in one hand, and a scalpel in the other, peeling away thin layers to examine cellular reaction.
"You're lucky you have me helping you with this," she said, glancing sideways.
"Most of Kabuto's regeneration work is rooted in deep tissue manipulation. Even advanced medics wouldn't understand half of this without killing themselves or their patient."
"That's why I asked the best," Kakashi smirked slightly.
"Flattery won't get you more samples." Tsunade snorted.
She leaned over, pointing to a diagram of chakra-threaded cell pathways. "This right here, Kabuto stabilized regeneration using some unknown enzyme infusions. It mimics the body's natural healing signals and then overrides them with chakra amplification. It's unstable unless you regulate it through a triple-core chakra node, see that?"
"It's like he's making the cells believe they're in emergency healing mode all the time." Kakashi nodded.
"Exactly," she said. "But it burns through stamina unless the body is enhanced to keep up. Kabuto modified himself like a lab rat. I wouldn't call that healing, more like self-hacking."
Kakashi scribbled notes on a scroll, carefully adding his own seal designs beside Tsunade's anatomical sketches. His mind was already moving several steps ahead, translating her anatomical insights into sealing formulae.
"You've been surprisingly eager to learn all this," Tsunade said after a pause, her tone becoming softer.
"I don't mind teaching you, really, but you haven't told me why. This goes way beyond helping the girls."
Kakashi didn't look up. "I want to understand the body better. If we're going to create seals that enhance healing or regeneration, I need to go beyond the surface."
"You're a terrible liar, but… I trust you." Tsunade studied him for a moment, then smiled faintly.
"Thank you." He met her eyes for just a second.
"Alright, then. Time for your next lesson." She rolled her shoulders and stood up.
For hours, they worked together. Tsunade explained the structure of stem cells and their chakra receptivity, the biological markers for transplant rejection, and the limitations of foreign gene grafts.
Kakashi soaked it all in, his enhanced perception letting him visualize how each element could interact with sealing matrices.
He started weaving medical chakra with far more control, even crafting micro-scale seals on tissue samples under Tsunade's supervision.
"You learn faster than any student I've ever had," she said, watching as he successfully regenerated a piece of cut skin tissue using a refined chakra pulse. "You could've been a legendary medic-nin if you wanted to."
"I had too many other things to worry about." Kakashi chuckled.
They paused for tea, both sitting on the couch in the corner of the lab, sipping quietly.
"You're not just learning to heal others, are you?" Tsunade leaned against him.
Kakashi stayed silent for a moment. Then he spoke, "I want to break my limits. I'm tired of being this weak. If I can refine these principles, maybe we can build something better, stronger."
Tsunade looked at him thoughtfully but didn't press. She had no idea how close to the truth she was.
Because deep down, Kakashi himself knew he wasn't just studying to heal or protect.
Hours later, after Tsunade had gone upstairs to rest, Kakashi stayed behind in the lab. The air was still, lit only by a single chakra lamp. He rolled out a different scroll, one not shared with anyone.
A forbidden scroll, retrieved not too long ago and tucked into his personal collection, the Chimera Technique. Exactly what he had been looking for.
He had learned about it from old Hunter-nin reports that a rogue shinobi had hidden his scrolls in the ruins of Hiruko's old base.
He didn't expect that Hiruko's subordinates were so stupid. But he also knew that Hiruko had shared this technique with others in the original plot.
It was an incomplete and unstable technique, meant to absorb the abilities of others, merging bloodlines and chakra natures by rewriting the user's DNA.
But Kakashi didn't want to use it recklessly. He didn't even want to use it in its original form.
He wanted to rebuild it and make it perfect.
That's why he studied Kabuto's cell manipulation and Orochimaru's transplant notes so seriously. If he could understand how to fuse DNA safely, without cellular collapse, without chakra rejection, then maybe… just maybe, he could unlock the dormant blood within himself.
His father had no Senju traits. His mother's lineage, though obscure, had faint indicators of Senju ancestry, recessive, mostly inactive.
But the potential was there. Kakashi naturally knew it thanks to his status panel, and the strange resilience in his body, a quiet resilience to chakra strain that no Hatake should've had.
The Chimera Technique, if perfected and he could modify it through his Formula Reconstruction Technique, maybe combining it with seals could let him awaken that latent blood. And he wasn't about to become a monster, so he wanted to modify it to his needs.
He unrolled a fresh diagram and began to write.
Stage 1: Target genetic trait. Stage 2: Chakra compatibility test. Stage 3: Host-Cell DNA Stabilization. Stage 4: Molecular seal fusion with Formula Reconstruction overlay.
Kakashi's hand moved quickly across the parchment, his mind constructing a safer version of the technique, one where chakra acted as a stabilizer, not a corrupter. If he could test it on artificial tissue first, or dormant cells extracted from blood samples…
He looked over to the vial Tsunade had given him earlier, containing Katsuyu's enzymes. With this, he created the Lotus Seal. It enhanced chakra, healing, and vitality. What if he used those enzymes to support cellular merging? Would the regenerative nature of slugs act as a biological buffer?
The idea was dangerous. Very Risky. But the potential was too great to ignore.