After weighing his options carefully, Kenji made his decision. He pulled the scroll containing the Four Symbols Seal from the shelf first. His living puppet technique relied heavily on sealing arts, and he still had Shukaku's chakra sitting in storage waiting to be dealt with. If Minato could use the Four Symbols Seal to imprison the entire Nine-Tails, using it to contain a portion of the One-Tail's chakra should be straightforward.
His plan was to memorize the Four Symbols Seal first, then move on to the Flying Thunder God Technique. He wasn't particularly confident about mastering the Flying Thunder God, honestly. Space-time ninjutsu required specific talent that you either had or didn't. No amount of effort could substitute for that. If he spent all his time memorizing a technique he might never be able to use, that would be a waste of valuable study time.
The Four Symbols Seal was vastly more complex than ordinary ninjutsu. The scroll was dense with technical diagrams, chakra flow patterns, and precise hand seal sequences that had to be executed perfectly or the entire seal would fail catastrophically.
Fortunately, his spiritual power far exceeded normal human limits. Even with that advantage, it still took him a full hour of intense concentration to completely commit the scroll's contents to memory.
He sat back when he finished, rubbing his throbbing temples. His head felt stuffed with information, like trying to cram too much data into too small a space.
Thank god for the mental boost. Without it, I probably would've needed all three hours just for this one seal.
He took a few minutes to rest and let the information settle properly in his mind, organizing it into something he could work with later. Then he immediately reached for the Flying Thunder God scroll.
The Flying Thunder God Technique was simpler than the Four Symbols Seal from a pure information standpoint. The reason it ranked as S-class wasn't complexity, it was the absurdly high requirements. You needed innate talent for space-time ninjutsu and massive chakra reserves. Because of that relative simplicity, it took less than an hour for him to memorize the complete technique.
That left him with about an hour remaining.
He didn't want to waste it. His eyes drifted to another entry visible in the Scroll of Seals: the Dead Demon Consuming Seal.
A thought occurred to him. What would happen if he used the Mind Body Switch Technique to control an enemy and forced them to cast the Dead Demon Consuming Seal? Who would count as the sacrifice? The controller or the controlled body?
In the original timeline, when Orochimaru had used the Shinigami Mask to undo the seal, he'd avoided the cost entirely by switching to a White Zetsu body through Living Corpse Reincarnation before the Shinigami could claim him. That raised questions about who the jutsu actually considered to be the "contracting party."
He didn't plan to test it anytime soon, obviously. Suicide techniques weren't his style. But having one more trump card never hurt, even if it was a last-resort mutual destruction option. Sometimes knowing you could take your enemy with you was deterrent enough.
The Dead Demon Consuming Seal, like many advanced sealing techniques, originated from the Uzumaki clan. The content was dense and intricate. He spent his remaining time completely focused on memorizing every detail before finally standing to leave.
"I've memorized three techniques," he reported to the waiting ANBU operative. "Four Symbols Seal, Flying Thunder God Technique, and Dead Demon Consuming Seal."
The ANBU didn't ask questions. He simply logged the technique names in his records. The registration system existed to track who learned what forbidden jutsu, preventing accusations of theft later. Of course, writing down that you'd studied something didn't mean you could actually use it. That was your own problem to solve.
The moment Kenji got home, he went straight to his workshop and started transcribing everything from memory onto fresh scrolls. Writing it down was critical. Memory could fade or distort over time. One wrong line in a sealing formula could lead to catastrophic failure when you tried to actually use it.
Once he'd documented all three jutsu completely, he set aside the Flying Thunder God and Dead Demon Consuming Seal scrolls and focused entirely on the Four Symbols Seal.
Shukaku's chakra needed to be dealt with. That took priority. Tailed beast chakra could directly boost his combat power right now. The Flying Thunder God could wait, especially since he might not even have the spatial talent necessary to learn it. Spending months trying to master something he was incapable of would be a waste.
His original plan had been to seal Shukaku's chakra into one of his combat puppets. But after studying the Four Symbols Seal in detail, he'd changed his mind. Puppets were tools. Powerful tools, essential tools, but tools nonetheless. True strength came from the body itself.
That said, he had no intention of becoming a jinchūriki in the traditional sense. The psychological strain, and the risk of losing control? No thanks.
Instead, he'd seal the chakra into his prosthetic left arm. The puppet limb was already integrated with his body but remained technically separate. If something went wrong, he could remove it. And since it was sealed rather than truly hosting the beast, there would be no consciousness to fight, just raw chakra to draw on.
To be safe, he dedicated an entire month solely to mastering the Four Symbols Seal before attempting the sealing procedure.
New Year came and went during that time. He made brief courtesy visits to the Ino-Shika-Chō clan heads, social obligations he couldn't completely ignore. But aside from that, he stayed sequestered in his workshop, practicing the hand seals over and over until they were automatic, studying the theory until he could recite it backwards, running through the entire procedure mentally hundreds of times.
During his studies, he discovered something unexpected. The Dead Demon Consuming Seal actually incorporated portions of the Four Symbols Seal in its structure. By the time he'd fully mastered the Four Symbols Seal, he'd nearly mastered the Dead Demon Consuming Seal as well, at least theoretically. Of course, that technique could only be used once in a lifetime.
---
Finally, Kenji felt ready.
The day of the procedure arrived. He set up his workshop carefully, laying out all the tools he'd need. The scroll containing Shukaku's sealed chakra sat in the center of his workspace. Next to it, he placed his prosthetic left arm after carefully detaching it from his shoulder.
He'd already swapped it out for a spare puppet arm he'd prepared earlier, making sure he could still form hand seals and channel chakra properly with the replacement. Can't have your seal fail halfway through because you couldn't complete the sequence.
With everything in position, he took a deep breath and reviewed the Four Symbols Seal procedure one last time in his mind.
"Release."
He pressed his hand against the storage scroll. The sealing formula lit up, glowing lines spreading across the paper before dissolving. Red chakra burst forth immediately, a violent torrent of energy that filled the room.
Tailed beast chakra was different from human chakra. It felt wrong somehow, like it wanted to destroy everything around it just from existing. The air grew thick and hot, making it hard to breathe.
He ignored the discomfort and moved into action.
"Four Symbols Seal... Seal!"
His hands blurred through the complex sequence of hand seals. Twenty-one seals executed in perfect succession, each one precisely timed. Chakra flooded through his pathways, shaped and directed by his will into the specific pattern required for the sealing technique.
He slammed both palms onto the prosthetic arm.
Sealing formulas erupted from his hands, spreading across the artificial limb's surface. The sealing moved, forming intricate patterns that spiraled inward. They created a gravitational effect, a chakra vacuum that began pulling Shukaku's wild energy toward the prosthetic.
The tailed beast chakra resisted. It thrashed and fought against the pull, trying to escape. But the Four Symbols Seal was designed specifically to contain tailed beasts. Slowly, inexorably, the red chakra was drawn into the sealing space within the prosthetic arm.
Sweat dripped down his face from the effort of maintaining the seal. His muscles trembled from holding the position. The process took several minutes, an eternity when you were fighting to contain something that wanted nothing more than to break free and rampage.
Finally, the last trace of chakra was sealed away. The formulas converged and stabilized into a complete sealing array, locking the tailed beast energy inside.
But he wasn't done yet.
He'd deliberately left a channel open in the Four Symbols Seal, a controlled leak that would allow small amounts of the tailed beast chakra to flow out. After all, he didn't want to just imprison the chakra. He wanted to use it.
"Now for the second layer," he muttered.
The next step was adding another Four Symbols Seal on top of the first to create an Eight Trigrams Seal. This was the same method Minato had used to seal the Nine-Tails inside Naruto, a double seal that allowed the jinchūriki to gradually merge the tailed beast's chakra with their own.
Minato had been able to perform both Four Symbols Seals simultaneously in a single casting. Kenji wasn't anywhere near that level of skill yet. He had to do it in two separate steps. Fortunately, since he was only sealing a portion of Shukaku's chakra rather than an entire tailed beast, the precision requirements were lower.
He went through the sealing sequence again, layering the second Four Symbols Seal over the first. The two formulas interlocked. When the second seal locked into place, they merged completely, forming the Eight Trigrams Seal.
The black markings on the prosthetic arm's surface faded, becoming invisible. The presence of the tailed beast chakra vanished. If he hadn't known it was there, he wouldn't have been able to sense it at all.
"It's done. Now let's test it."
He couldn't wait. He reattached the modified prosthetic to his shoulder, making sure the connections were secure, then attempted to activate the seal by channeling his chakra into it.
Red chakra exploded from the prosthetic arm, surging across his entire body in a crimson wave. It spread over his skin, forming a thin layer that clung to him like a second skin. The Tailed Beast Cloak, the signature transformation of jinchūriki.
"Holy shit," Kenji said, staring at his chakra-shrouded hands. "It actually formed a cloak?"
The sensation was incredible. His chakra reserves had increased by at least fivefold, maybe more. Power coursed through his body. He felt like he could punch through a wall without even trying.
But there were downsides. Even without Shukaku's consciousness present, the tailed beast chakra still affected his mind. He could feel it tugging at his emotions, trying to amplify aggression and violence. His spiritual power was strong enough to resist the influence and adapt to it, but a weaker-willed person would've lost control immediately.
He checked the seal's status through his chakra sense. About half the stored tailed beast chakra had been consumed to maintain this cloak form. That was his current limit without the foreign chakra overwhelming his system.
"I can't be greedy. This was free power anyway. Having it at all is a gain."
He raised his hand and focused. A swirl of sand began gathering slowly in his palm, responding to his will.
"Sand manipulation," he murmured, watching the grains dance. "Just like Gaara."
He experimented with shaping the sand into various forms. Spheres, blades, defensive walls. The control was crude compared to what Gaara could do, but it was there. And more importantly, it would improve with time. The longer Shukaku's chakra remained in his system, the more his body would adapt to it. Eventually, like Gaara, he'd be able to control sand even without actively drawing on the tailed beast's power.
He maintained the Tailed Beast Cloak for a full hour before drawing the chakra back into the seal. When he checked again, about one-fifth of the stored chakra had been consumed.
But he wasn't worried about running out. Tailed beasts were chakra-based lifeforms. They didn't need food or rest. Their chakra naturally regenerated by absorbing ambient energy from the environment. As long as he didn't completely deplete the sealed chakra in one go, it would gradually refill on its own.
"Tailed beasts really do make excellent energy sources for puppets," Kenji noted to himself, flexing his prosthetic fingers. The modified arm felt no different than before. "Still, I should prioritize finding Edo Tensei. That technique's method of converting natural energy into chakra would be perfect. Tailed beast chakra is way too hard to obtain consistently."