There was a sharp crack.
The starfall iron split down the middle, and a flying fragment struck the rock wall, leaving a white pit the size of a pinprick.
Holding half the ruined piece, Rinto brought it under the lamp and examined it for three seconds, then casually hurled it into the iron box by his feet. The box was already nearly half full of fragments, all material he had ruined over the past two days. The gauze around his right hand had long since frayed at the edges, and blood mixed with iron filings had crusted over it. He pulled it off and tossed it into a pile of wastepaper. The cut underneath was still bleeding, but he did not so much as raise his eyelids.
His eyes felt gritty from staying up. He blinked hard twice, rubbed the dried crust from their corners, and fixed his gaze back on the detector screen.
Particle data for senjutsu chakra flickered across the screen, red and green lines tangled together. Ordinary chakra used spirit to anchor life, a binary structure. He had been engraving it for over a decade and could draw its patterns with his eyes closed. But senjutsu chakra added natural energy, and that stuff simply would not obey the spiritual anchor. Like water he could not grasp, it dissipated completely before getting halfway through a one-way pattern, or collided with life energy at a corner and blasted the entire pattern apart.
Eight attempts.
Even his best attempt had held steady for less than ten seconds before every trace of its senjutsu properties dissipated, leaving only a little ordinary Wind Release power.
He leaned back, the chair legs scraping shrilly across the concrete floor. The desk was so cluttered there was nowhere to put his hands. A half-eaten rice ball had sat there for two days and was hard as stone. Half a bottle of distilled water had spilled, soaking part of a stack of rough paper and bleeding the ink on the discarded designs, but he could not be bothered with it. He pushed things aside a couple of times and dug out the Cursed Seal experiment scroll Orochimaru had given him earlier from the very bottom.
Before, he had only glanced at the locking model's effects without examining the details. Now that his thinking had hit a wall, he pulled it out to try his luck.
He unrolled the scroll, packed with tightly crammed experimental records. He flipped through it quickly, his gaze passing over page after page of chakra fluctuation curves before finally settling on the Cursed Seal's basic configuration diagram-Orochimaru had added a ring-shaped adsorption structure to its patterns. Even without activation, it could draw on trace amounts of the subject's life energy to keep the configuration from collapsing.
Rinto's fingertips stopped.
Until now, he had kept thinking about how to lock natural energy inside the patterns, but the harder he locked it down, the more it collapsed. Since he could not lock it down, could he let it move instead?
He abruptly leaned forward, hitting the workbench with a clatter, grabbed a charcoal pencil, and began drawing on a blank sheet of rough paper. The tip tore through the page, leaving crooked, closed lines. This was not the one-way path from inlet to outlet he had used before. It was a closed loop.
He would let the ternary chakra circle through the loop, with spiritual anchor points moving along with the circulation. Wherever they went, they would draw the dissipating natural energy back in. Rather than locking it rigidly in place, he would let it maintain balance through motion. When he needed to release it, he would open an outlet and channel it out.
Halfway through the drawing, the pencil core snapped. Irritated, he threw the broken pencil away, fished out another charcoal pencil, and kept revising. The curvature of the corners, the circumference of the loop, the spacing between anchor points-he revised and crossed things out, then crossed things out and revised them again. The sheet became such a mess that only he could understand it.
Footsteps sounded outside, so faint they were almost inaudible. Kabuto pushed open the door and leaned halfway inside. Seeing Rinto bent over the desk drawing designs, he did not dare speak. He quietly set a food box beside the door, then placed a new bundle of glass tubes on the materials rack. Just as he was about to leave, Rinto spoke without raising his head. "Leave it there. Come over and organize the dissipation-rate data from the previous eight collapses by pattern segment."
Kabuto froze for a moment, then immediately answered, "All right." He walked over quietly, picked up the detector and record book, and crouched on the floor to go through the scrap iron, measuring the data from the remaining patterns one piece at a time.
When he reached the eighth piece, Kabuto could not help looking up. He glanced at the closed-loop design on the paper and asked softly, "Mr. Rinto, are you making a circulating pattern? Lord Orochimaru tried sealing senjutsu chakra inside a closed loop before, but once the balance broke, it exploded even more violently than a one-way pattern."
"His loop was static. He didn't leave any tracking anchor points." Rinto's pencil never stopped as he tossed out the reply. "Don't ask what you shouldn't. Give me the data once you've organized it."
Kabuto's hands paused. He immediately shut his mouth, asked nothing more, and lowered his head to finish recording the data.
Half an hour later, Kabuto placed the organized data at the edge of the desk. Rinto glanced at it, tapped the paper twice with his fingertips, and said nothing more. Taking the hint, Kabuto cleared away the food box by the door whose contents had spoiled and quietly withdrew. The moment he closed the door, he heard the faint sounds of an engraving knife touching metal begin again inside.
Those sounds continued all night.
The sky outside went from black to gray, then from gray to light. Morning light came through the vent and cast a long, narrow shadow on the floor, but Rinto noticed none of it. He remained planted in front of the vise, breathing so lightly that he seemed afraid of blowing the engraving knife off course. The piece of starfall iron was only the size of a fingernail, and he had to engrave a closed circulation pattern on it. The spacing between each line was less than 0.02 cun. One slight mistake would ruin the entire loop.
After making the final cut and closing the loop completely, he set down the engraving knife and flexed his stiff wrist, his knuckles cracking. His hand was badly numb. He clenched it twice before carefully removing the starfall iron from the vise.
Walking to the steel-plate target, he took a deep breath, first mixed the ternary chakra at a 1:1:1 ratio, then held the black piece of iron between his fingertips and slowly fed chakra into it.
Buzzz-
With an extremely faint vibration, a pale green glow rose over the surface of the starfall iron. It did not flash and vanish; it shone steadily. The detector was pressed close beside it, and the ternary-ratio curve on its screen was as flat as a straight line. There was no dissipation, no imbalance. The chakra circulated steadily through the pattern.
Rinto shifted his fingertips, triggering the release outlet.
A pale green wind blade shot out instantly. There was no loud crash, only a hiss as it punched straight through the steel plate, more than ten centimeters thick. The walls of the hole were smooth. Even the surrounding metal had been rendered brittle by the senjutsu chakra, developing a ring of fine cracks.
He waited another five minutes. The starfall iron in his hand still glowed faintly. The circulation had not stopped, and the balance had not broken.
Rinto casually placed the starfall iron on the desk, grabbed a sheet of rough paper, and began recording data. His pencil flew as he muttered parameters, all details such as corner curvature and anchor-point spacing. He had completely forgotten that he had gone nearly two days without sleep and nearly a day without eating.
Only after he finished recording the data did he notice the food box at the edge of the desk. Kabuto had delivered it that morning, and it had long since gone completely cold. He picked it up and shoveled down the cold rice in a few mouthfuls. When it stuck in his throat, he picked up the half bottle of distilled water that had been sitting on the desk for three days and gulped down most of it.
He had just tossed the empty food box aside when the laboratory door opened.
Orochimaru walked in, the hem of his black clothes brushing the wastepaper on the floor. His golden, slit-pupiled eyes swept over the hole through the steel plate, then settled on the piece of starfall iron still glowing faintly on the desk. The corners of his mouth curled into a hissing smile.
"Kabuto said you succeeded in solidifying senjutsu chakra." He walked to the workbench, picked up the starfall iron between his fingertips, and injected a thread of his own chakra. The pale green light instantly brightened. The circulation structure was astonishingly stable. Even when he increased the chakra input, it showed no signs of collapse.
Orochimaru's fingertips tightened slightly. He had researched senjutsu for so many years, yet even his Cursed Seal relied on a human body to stabilize senjutsu chakra. He had never imagined that this stuff could be sealed inside a lifeless piece of iron and remain this stable.
"I stumbled onto the right approach." Rinto put away the data he had just recorded, his tone calm and unruffled. "You didn't come looking for me just to compliment me, did you?"
"As direct as ever." Orochimaru smiled and set the starfall iron back on the desk. "There's been a little problem with the Cursed Seal experiments."
"The locking model stopped working?"
"It works." Orochimaru tapped the workbench with his fingertips. "With the locking model you gave me, all the subjects survive, but their compatibility rates vary too much. Some can release eighty percent of the power, while others can't even manage thirty percent. A few have even begun slowly showing rejection reactions despite the lock."
He paused, his golden eyes fixed on Rinto. "I need an adjustable locking template, one whose compatibility parameters can be altered according to different people's chakra configurations."
Rinto looked up at him and frowned.
The locking model he had provided before was a universal, fixed framework. He had not touched anything involving the human body. But this adjustable template would essentially serve to implant Cursed Seals in more living people. It crossed his red line.
"No." His refusal was crisp, without a single word of explanation.
Orochimaru's smile faded a little, and his tongue lightly licked his lower lip. "Don't be so quick to refuse. As long as you make it, I'll give you all of Ryūchi Cave's senjutsu materials, along with the natural energy collection and stabilization data. I can even take you to Ryūchi Cave to experience the natural energy there for yourself."
Rinto merely shook his head and put away the engraving knives on the desk, his tone unwavering. "I said no. I don't touch experiments involving the human body. When I gave you the locking model, I only provided a general logic. Using it on living people was your business. Having me specifically adapt it for your experiments on living subjects is out of the question."
"Don't you want to understand senjutsu configurations completely?" Orochimaru stepped half a pace closer, a cold, sinister aura spreading from him. "Without that data, this is as far as your solidification research will go."
"That's my business." Rinto raised his eyes to meet his gaze without the slightest retreat. "At worst, I'll go back to that broken-down wooden hut by the village and work it out slowly myself. If you revoke my access to materials over this, that's fine too."
Orochimaru stared at him for a long while. Emotion stirred in his golden pupils before he finally suppressed it. He could not afford to fall out with Rinto. The Cursed Seal research had only just begun to show progress, and whether he wanted to optimize or expand it, he could not get around Rinto's configuration theory. Besides, what this kid had in his head went far beyond what he had revealed so far.
Suddenly, he smiled again, as though the pressure from a moment ago had never existed. "Fine. I won't force you. I was presumptuous."
He did not mention the template again. Instead, he exchanged a few words with Rinto about the senjutsu circulation structure and asked a couple of questions about natural energy dissipation. Rinto casually answered a few things that did not involve the core principles and said little else.
Within a few minutes, Orochimaru left. Before leaving, he placed a scroll of basic senjutsu materials from Ryūchi Cave on the corner of the desk. He mentioned no conditions, as though he had simply happened to leave it there.
Rinto glanced at the scroll without touching it. Only after the door closed did he pick it up, open it, and leaf through it. It contained environmental data on Ryūchi Cave's natural energy, along with basic balance formulas for senjutsu chakra—exactly what he could use right now.
He tore out the few useful pages, casually tossed the rest aside, then turned and picked up the engraved piece of starfall iron. Bringing it close to the detector, he began measuring the energy loss during circulation again.
The sky outside had gone completely dark. The night breeze pouring through the vent carried a chill, but he did not notice. The soft scrape of the engraving knife across starfall iron drifted through the empty laboratory. He stared at the iron in his hand, the engraving knife between his fingertips falling steadily and precisely.