The underground laboratory's lights had been burning for four days and nights.
The air carried the acrid smell of crystal jade powder mixed with reagents. On the floor of the separate laboratory on the west side, discarded crystal jade filled nearly half a basket. Most pieces had split in two down the middle, or had their patterns blasted into pockmarks. Even the surrounding rock walls were embedded with fragments from the explosions.
Rinto hunched over the workbench, his chin almost touching its surface, his eyes less than half a fist from the crystal jade in his hand. Two layers of dirty gauze wrapped the hand holding his engraving knife, dried blood seeping through the edges. The cuts came from a piece of crystal jade that had shattered when he carved a pattern incorrectly before dawn yesterday. He had grabbed a cloth used for wiping reagents, wrapped it around his hand, and ignored it ever since.
All his attention was on the tube of Scorch Release chakra in his hand, with only a little left at the bottom.
Three days ago, he had barely finished figuring out Ice Release's interlocking configuration before plunging into dismantling Scorch Release. He had assumed that since both were dual-attribute composite configurations, his experience with Ice Release would let him reproduce it in two days at most. Only when he actually tried did he discover they were completely different.
His earlier fire-wind transitional configuration converted chakra to fire first, then wind, using a transitional section as a buffer. The result was wind blades wrapped in flames, with "sequential linkage" at its core. Ice Release's dual-track configuration sent water and wind along separate patterns before interlocking them at the outlet, with "parallel operation without interference" at its core. But this Scorch Release sample completely overturned both his previous models.
Inside the glass tube, the spiral structures of Scorch Release's fire attribute and the scattered structures of its wind attribute were entwined from the very root. Every spiraling fire particle was tightly wrapped in fine wind particles. They were neither sequential nor parallel, but completely interwoven, each contained within the other. It was precisely this structure that allowed the chakra to release nothing but extreme heat without exploding, instantly evaporating even water.
None of his previous approaches worked.
He had revised his drawings more than twenty times and ruined over thirty pieces of crystal jade. His best attempt had only produced a gust of hot air carrying sparks, unable even to heat a steel plate red. It was a world away from true Scorch Release.
"Fuck." Holding half a freshly shattered piece of crystal jade, Rinto swore and tossed it into the basket. His fingers were so stiff from gripping the knife for so long that he could not straighten them. He raised the sample tube to the light and stared at the little pale red chakra remaining inside, his brow furrowed tightly enough to crush a mosquito.
The sample was almost gone. If he still could not figure out its core structure, he would have to ask Orochimaru for more. But he did not want to owe favors, much less waste his own time over something like this.
As he stared blankly at the sample tube, the laboratory door was gently pushed open.
Kabuto stepped in quietly, carrying a food box, with a stack of blank scrolls and several sealed glass tubes tucked beneath his arm. Seeing the discarded crystal jade covering the floor and Rinto's bloodshot eyes from staying up, he showed no surprise at all. Wearing his usual gentle smile, he set the food box in the only empty spot on the corner of the table.
"Mr. Rinto, the cafeteria just made dinner. It's still hot." Kabuto placed the glass tubes on the materials rack, keeping his voice soft. "Lord Orochimaru asked me to bring you fresh Scorch Release chakra samples, as well as two residual samples from Iwagakure Explosion Release shinobi. You mentioned them once before, so he specifically had someone obtain them."
Rinto's ears twitched, and his head immediately turned. His gaze locked onto the new sample tubes at once, completely ignoring the food box. He reached out and took the tubes, checking their labels one by one against the light, his fingertips trembling slightly. With fresh Scorch Release samples, he could dismantle them a few more times. The Explosion Release samples would also let him compare the structural principles of interwoven dual attributes.
"Thanks." He offered a rare word of thanks, casually tossed the nearly empty old tube aside, and picked up a new Scorch Release sample to put into the analyzer.
Watching him, Kabuto could not help reminding him, "Mr. Rinto, please eat something first. You haven't touched the rice balls I left this morning. If you keep pushing yourself like this, your hand won't stay steady, and you'll only make more engraving mistakes."
Rinto paused, glanced at the food box on the corner of the table, then at the sample in his hand, and finally set the tube down. He really was hungry. It had been almost thirty hours since he had eaten a couple of bites of a rice ball before dawn yesterday, and his hand had already felt a little unsteady while holding the knife earlier.
He grabbed the rice balls from the food box and stuffed them into his mouth in a few bites, frowning as they caught in his throat. Too lazy to look for water, he took a couple of swigs from a half-full bottle of distilled water that had sat on the workbench for two days. In less than three minutes, he had cleaned out the entire box.
After eating, he pushed the food box aside, picked up the analyzer probe, and was about to insert it into the sample tube when something occurred to him. He turned toward Kabuto, who had yet to leave.
Kabuto was Orochimaru's assistant and had spent several years helping with his experiments. He was far more practiced than Rinto at basic chakra analysis and data recording. Until now, Rinto had been measuring data and engraving patterns himself, running between the two tasks and wasting considerable time.
"Can you measure chakra particle distribution?" Rinto asked bluntly, without the slightest preamble.
Kabuto froze for a moment, then nodded with a gentle smile. "Yes. I perform all the basic analyses for Lord Orochimaru's experiments."
"Then do me a favor." Rinto pushed the Scorch Release sample tube toward him and handed him a stack of blank scrap paper. "Measure everything in this sample: the entanglement ratio of fire- and wind-attribute chakra particles, their spin frequency, and their distribution density. The more detailed, the better. Get it to me in half an hour."
He did not ask whether Kabuto was willing or offer anything in return. To him, this was simply a way to improve experimental efficiency. Kabuto worked for Orochimaru, and Orochimaru was relying on him to solve the Cursed Seal problem, so it was only natural for Kabuto to help him work.
Kabuto showed no surprise. He immediately picked up the sample tube and nodded. "Of course. I'll measure it now and bring it back within half an hour." In truth, he had long been intensely curious about Rinto's research. After watching Rinto break down Kekkei Genkai so thoroughly these past few days, he had been eager to study his experimental reasoning up close. Now he had the perfect opportunity.
Kabuto left with the sample, and the laboratory fell quiet again. Rinto did not sit idle. Taking up a charcoal pencil, he redrew configuration sketches on scrap paper, turning the question over in his mind. Since the two kinds of particles were completely interwoven, could he divide attribute-less chakra proportionally from the outset and complete the interweaving within the patterns, rather than separating the attributes first and interlocking them afterward?
The more he drew, the more smoothly it flowed. The line of thought that had been stuck for days slowly took shape. By the time Kabuto returned with the measurements, he had covered nearly half a sheet with a new model.
"Mr. Rinto, the measurements are ready." Kabuto handed over the paper filled with data, his voice carrying a barely perceptible note of surprise. "The ratio of fire to wind particles is exactly 7:3. Four wind particles are fixed around each fire particle's spiral. The structure is extraordinarily stable, completely different from the earlier Ice Release configuration."
He had been shocked himself while taking the measurements. He had seen many Kekkei Genkai samples while working with Orochimaru, but never such a precise chakra structure. No wonder Rinto had been stuck for so long.
Rinto took the paper, glanced over it, and his eyes instantly lit up. The data matched his conjecture perfectly. The ratio had been his stumbling block all along. He had kept using 5:5. No wonder nothing worked.
"All right, thanks." Rinto nodded, his fingers rapidly annotating the data on the paper without raising his head. "That's everything. Go take care of whatever you need to do."
Standing beside him, Kabuto watched his hand rapidly revise the drawing and studied the crooked yet rigorously logical patterns on the paper. He could not resist asking, "Mr. Rinto, are you trying to engrave Scorch Release's configuration directly into crystal jade? To release Scorch Release without hand seals or a bloodline?"
"What else?" Rinto glanced up, his tone flat, as though stating the obvious. "Once you understand the structure, engraving it is only a matter of time."
Kabuto was shaken.
Throughout over a century of the Shinobi World's history, Kekkei Genkai had always been talents carried in the blood, the foundation of the great clans' monopoly on power. But to Rinto, bloodlines and talent meant nothing. As long as he broke down the chakra structure clearly, he could reproduce it with a piece of crystal jade. If word of this spread, the entire Shinobi World would be turned upside down.
He asked nothing more, bowed, and quietly withdrew. He had to tell Lord Orochimaru about this. Rinto's system was even more astonishing than they had expected.
After Kabuto left, Rinto immersed himself completely in the new configuration. With precise ratio data, the previous bottleneck cleared at once. He redesigned the patterns, abandoning dual tracks for interwoven patterns like braided dough. Starting at the inlet, they divided chakra at a 7:3 ratio, simultaneously converted its attributes to fire and wind, then interwove the two kinds of particles within the patterns before releasing them through the outlet.
He took a fresh piece of crystal jade, secured it in the vise, drew a deep breath, and lowered his knife.
This time, he engraved even more slowly than he had with Ice Release. The spacing between the interwoven patterns was less than 0.02 cun, finer than a strand of hair. A single micrometer's error would make the two kinds of particles collide and shatter it outright. His breathing slowed to a crawl. He seemed nailed to his chair, only his knife hand moving with machine-like steadiness, every cut landing precisely where intended.
Outside the window, the sky went from dark to light, then light to dark, without him noticing at all. By the time he finished the last stroke and set down his knife, morning footsteps could already be heard in the research and development department outside. He had stayed up another entire night.
Rinto rolled his stiff shoulders and removed the crystal jade from the vise. The fingernail-sized piece was filled with intricate interwoven patterns. Held against the light, it looked as though a whole expanse of tangled starlight had been sealed inside.
He walked to the steel target plate, held the crystal jade between his fingers, and injected a trace of his own attribute-less chakra.
There was no explosion or blinding light, only a wisp of pale red heat drifting from the crystal jade's tip. It looked unremarkable, but the instant it touched the thick steel plate, a faint sizzle sounded. The plate immediately turned red-hot, then melted through. Even the molten metal evaporated instantly, leaving only a smooth-edged hole, while the surrounding steel remained scorching hot and warped.
It worked.
Rinto's eyes shone with startling brightness. He tested it three more times, and every release was stable, without shattering or chakra leakage. The conversion rate was even higher than Ice Release's. He immediately grabbed some scrap paper and rapidly recorded the experimental data, not even caring that his hand was shaking uncontrollably from holding the knife for so long.
Halfway through recording the data, the laboratory door opened, and Orochimaru walked in.
His golden slit pupils immediately landed on the melted hole in the steel plate, then swept over the crystal jade in Rinto's hand. A meaningful smile curled his lips as he drawled in his hoarse voice, "It seems you've figured out Scorch Release as well. Rinto, you never fail to surprise me."
Rinto raised his head, folded the paper covered in data, and tucked it into his pocket. Casually tossing the crystal jade onto the workbench, he said evenly, "Just got it working. There's still room for optimization. Did you need something?"
He knew Orochimaru all too well. Without a reason, he would not casually interrupt his experiments. Something must have gone wrong with the Cursed Seal experiments again.
Sure enough, Orochimaru walked over, placed a thick scroll on the table, and tapped it with a fingertip. "It's the Cursed Seal again. With your buffer model, the subjects can survive, but the buffer layer also dissipates most of the Cursed Seal's power. Even when we manage to activate it, it only produces thirty percent of its strength. Increase the Cursed Seal's concentration any further, and the subjects still disintegrate."
He had thought that as long as the subjects survived, he could gradually optimize things afterward. He had not expected the buffer model to preserve their lives while also locking away the Cursed Seal's power. He had spent nearly a week revising it and trying every method, but either he could not keep them alive or he could not release the power. Unable to find a balance no matter what he did, he could only come to Rinto again.
Rinto frowned. His first words were, "I don't do human experimentation. I told you that before."
"I know." Orochimaru chuckled and leaned half a step closer, his tone enticing. "I don't need you to touch living subjects. I only need a new model that prevents the Cursed Seal's configuration from interfering with the host's chakra while allowing it to release its full power upon activation."
He paused, then offered a bargaining chip Rinto could not refuse. "In exchange, I'll give you an original sample of Ryūchi Cave's senjutsu chakra, along with complete configuration data for the Cursed Seal's entire process, from implantation to activation to disintegration. Not a single piece missing."
Rinto's eyes instantly lit up.
Senjutsu chakra.
Previously, he had only seen related data in Orochimaru's experimental records, never obtaining an original sample. Senjutsu chakra was completely different from ordinary chakra, a brand-new configuration incorporating natural energy. To him, this was an entirely unexplored field, far more enticing than Scorch Release or Ice Release.
He had wanted to ask Orochimaru for some before, but had never found a suitable pretext. Now it had come straight to his door.
"Where's the sample?" Rinto went straight to the point, without a wasted word or any bargaining.
Orochimaru smiled, took a sealed glass tube glowing pale green from inside his clothes, and placed it on the table. The chakra inside carried faint fluctuations of natural energy, entirely unlike ordinary chakra. Even looking at it, one could sense the violent power it contained.
"An original senjutsu chakra sample, far purer than what's refined into the Cursed Seal," Orochimaru said. "As long as you can produce a working model, I can give you all the subsequent experimental data too."
Rinto immediately reached for the glass tube and studied it against the light for a long time, his fingertips itching slightly. An entirely new energy structure, entirely new configuration logic. To him, this was more precious than any rare material.
Only after carefully placing the sample tube in a corner of the workbench did he pick up Orochimaru's scroll and open it to examine the experimental data. He turned the pages quickly, his gaze sweeping across chakra fluctuation curves and configuration diagrams as his mind started working.
The previous buffer model broke the Cursed Seal's configuration into pieces and embedded them in the host. It was like rounding off a foreign stone and stuffing it into sand. Though it no longer hurt anyone, it could no longer move either. To preserve its power, the configuration could not be broken apart. It had to remain intact.
"The buffer model won't work anymore." Rinto finished the last page, set down the scroll, and began drawing on scrap paper with his charcoal pencil. "Your previous approach was wrong. Not interlocking. Isolation."
His pencil swiftly drew a circle, then a separate small square inside it. "Lock the Cursed Seal's complete configuration inside an independent space, anchored to the subject's chakra core. Keep it completely isolated normally, with neither its chakra nor the host's interfering with the other, and there won't be any conflict at all. When you want to activate it, just open the lock and release the Cursed Seal's power. Lock it when it's not in use, and it won't have any effect."
Orochimaru's golden pupils abruptly contracted.
The dead end he had spent days trapped in had been cleared up by a single remark from Rinto. He had been fixated on merging and adapting the two configurations. It had never occurred to him simply to keep them from touching, eliminating conflict at its root through isolation.
"What do we use to make this spatial lock?" Orochimaru immediately pressed, urgency in his voice. After working on the Cursed Seal for so long, this was the closest he had ever been to success.
"Use spiritual energy as the anchor and inscribe a locking configuration," Rinto said as he drew. "The lock's core must be the subject's own spiritual imprint. Only he can open it. No one else can control it, and there won't be any Cursed Seal backlash. Your previous Cursed Seals carried your own spiritual imprint. Even after implantation, they would clash with the subject's spiritual energy. That's another cause of disintegration."
He drew quickly. Before long, a complete "locking configuration" model was finished, clearly laying out the isolation layer's patterns, the anchors' positions, and the lock's triggering logic. Even someone who only understood basic configurations could follow it.
Once finished, he pushed the paper toward Orochimaru and turned back to the senjutsu chakra sample, as though solving a problem that had plagued Orochimaru for almost a year had been no more than casually writing down a formula.
"You have the model. Whether it works depends on your own experiments." Rinto did not even turn around. "Remember to send me a copy of the subsequent data, especially the changes in the senjutsu chakra configuration after the Cursed Seal activates."
Orochimaru picked up the paper and stared at the locking model for a full five minutes. The more he looked, the more astonished he became. This model completely transcended the Shinobi World's established understanding of Cursed Seals and chakra fusion. Its logic was so rigorous that he could find no flaw. It even resolved the spiritual imprint conflict he had previously overlooked.
He had originally thought Rinto was merely a youngster with some talent for solidifying techniques in ninja tools. Now, however, it seemed the boy's understanding of chakra's essence surpassed his own by more than one order of magnitude.
"Very well." Orochimaru folded the paper and carefully put it away, his tone unusually earnest. "Once the data is ready, I'll have Kabuto bring it to you immediately. Use any resources in the laboratory you like. If you want anything, just tell Kabuto."
Rinto murmured an acknowledgment. He had already picked up the senjutsu chakra sample and leaned toward the analyzer, paying Orochimaru no further attention. To him, the Cursed Seal matter was settled. What mattered now was this tube of entirely new senjutsu chakra, a field he had never explored before.
Watching his back, Orochimaru did not interrupt him again. He turned and quietly left. His mind was now filled with the new locking model, and he could hardly wait to revise the Cursed Seal's configuration and conduct new experiments.
Rinto was alone in the laboratory again.
He had completely forgotten the Scorch Release configuration from earlier and the exhaustion of staying up all night. His eyes held nothing but the tube of pale green senjutsu chakra. Particle data refreshed on the analyzer's screen. As he studied the ternary structure, entirely unlike ordinary chakra, his eyes shone with startling brightness.
Ordinary chakra had a binary structure of spiritual energy and life energy. After studying it for over a decade, he had long since understood it thoroughly. Senjutsu chakra, however, had a ternary structure of spiritual energy, life energy, and natural energy anchored in balance. With an entirely new variable, the logic of the whole configuration was completely different.
He sat at the workbench for an entire day, measuring data, drawing sketches, and dismantling structures. He never even touched the lunch Kabuto brought, leaving it beside him until it went completely cold.
Toward evening, Kabuto came again, bringing the basic Cursed Seal configuration data Orochimaru's side had just compiled. Rinto was still in the same position as that morning, hunched in front of the analyzer, his charcoal pencil moving incessantly across scrap paper. A good number of discarded drawings had accumulated on the floor.
Kabuto did not dare disturb him. He placed the data on the edge of the table and quietly withdrew. From then on, however, his daily visits grew more frequent. Sometimes he brought samples, sometimes food, and sometimes new experimental data from Orochimaru.
Rinto gradually grew accustomed to having someone lend a hand. He handed all the miscellaneous tasks—basic measurements, organizing experimental records, requisitioning materials—to Kabuto, pouring every moment saved into configuration research. Kabuto was happy to help. He could report Rinto's progress to Orochimaru while getting a close look at this understanding-defying configuration science. The two had a tacit arrangement of mutual use.
A week later, Orochimaru's Cursed Seal experiments made a breakthrough. Using Rinto's locking model, the first subject not only survived but could fully activate the Cursed Seal's power. His chakra remained orderly, and his body showed no signs of disintegration.
When Orochimaru sent Kabuto over with the complete experimental data, he also sent an entire box of high-purity crystal jade and plenty of rare metals. He even included a sizable amount of starfall iron scraps, which Rinto had once mentioned had better energy conductivity than crystal jade.
Rinto glanced at the data and tossed it aside, his attention entirely on the starfall iron in his hand. Until now, he had always engraved configurations in crystal jade. With a better medium, he could finally try more complex ternary structures, or even multi-attribute composite configurations.
He had no idea how great a storm his chakra configuration science had already stirred in Orochimaru's experiments. Nor did he have the inclination to consider how profoundly Konoha and the entire Shinobi World would be shaken if word spread that he could reproduce Kekkei Genkai.
His world held only chakra structures, an engraving knife, and experiments that would never end.
Night deepened once more, and the underground laboratory's lights still shone dazzlingly bright.