At first light, Kabuto knocked on the laboratory door.
He carried a food box and a stack of glass tubes wrapped in soft cloth. Pale blue chakra solutions were sealed inside the tubes, with clearly marked labels listing their attributes, their donors' ranks, and their chakra activity.
The door was unlocked. When Kabuto pushed it open, he saw Rinto still hunched over yesterday's workbench, his back to the door, his shoulders rigid, and the carving knife still moving in his hand. Three or four ruined pieces of crystal jade lay scattered across the bench. Some were cracked, others had crooked patterns carved into them. The scrap paper beside them was covered in messy drawings. A rice ball sat untouched in the corner, hard as a rock.
"Mr. Rinto, Lord Orochimaru sent me to deliver the chakra samples you requested." Kabuto softened his footsteps and lowered his voice, afraid of disturbing him.
Rinto's hand paused before he turned around. His eyes were bloodshot, his hair disheveled, and white crystal jade powder smudged his face. A layer of dark stubble had sprouted along his chin. He looked thoroughly worn out, yet his eyes were startlingly bright, and his gaze immediately landed on the glass tubes in Kabuto's hands.
"Put them here." He beckoned, still holding the carving knife. There was a little blood on the cloth wrapped around his fingertips, where the knife had slipped and grazed him earlier. He acted as though nothing had happened.
Kabuto set the samples on the bench, then pushed the food box forward. "The cafeteria just made breakfast. It's hot. Please have something to eat. You've been up all night."
"Mm." Rinto answered, already reaching over to unwrap the stack of glass tubes. His elbow brushed the food box, sending it sliding to the edge of the bench. He did not even glance at it.
Kabuto opened his mouth, but said nothing more. Following Orochimaru, he had met plenty of obsessive lunatics, but never anyone so heedless of his own life. Once inside the laboratory, Rinto seemed to see nothing but those stones and patterns. Kabuto quietly backed out, stopping to pick up the discarded scrap paper scattered across the floor. The moment he touched a sheet, Rinto turned around, frowning deeply. "Don't touch those. I know where everything is."
"Sorry." Kabuto immediately withdrew his hand. Without touching anything else in the room, he left and closed the door behind him.
The laboratory fell quiet again. Holding the glass tubes up to the lamp, Rinto examined them one by one. Fire, water, lightning, earth-five samples of each, with donors ranging from genin to jonin. There were even two samples of residual chakra from Kekkei Genkai shinobi, labeled "water + wind, Ice Release."
Orochimaru really had shown every sincerity.
He left the two Ice Release samples alone and took a fire-attribute sample first. Previously, he could only force his own attributeless chakra to convert, which produced large errors and inaccurate data. Now that he had ready-made elemental samples, he could finally thoroughly understand the configurations of the different attributes.
Carrying the samples and carving knife, he shut himself inside the separate laboratory on the west side. Kabuto had tidied it up yesterday, arranging the workbench, equipment, and material racks in perfect order. Less than ten minutes after Rinto entered, it was a mess. Scrap paper covered the table, unsealed glass tubes stood in a row, and carving knives and files lay everywhere. Even the floor had two half-finished configuration diagrams on it.
First, he reproduced the standard configurations of all five basic attributes in crystal jade. Previously, he had only made basic versions for Wind Release and Fire Release. Now, with the samples, he could measure the particle flow patterns and optimal carved patterns for every attribute.
The carving knife made faint scraping sounds against the crystal jade. Although he had stayed up all night, his hand remained steady, every cut precise, even his breathing matching the rhythm of the blade. At the slightest mistake, he tossed the crystal jade aside and started again with a fresh piece, without a hint of regret.
In the past, ruining one piece of crystal jade would have pained him for half a month. Now, with Orochimaru's material stores behind him, he could experiment freely.
At noon, Kabuto came again with lunch and found the breakfast box sitting untouched by the door, the porridge inside already congealed. He knocked, but only the sound of the carving knife came from within. No one answered. Kabuto sighed, took away the old food box, and left the new one by the door, not daring to go in and disturb him again.
Only when the sun sank toward the west did Rinto finish carving the standard configurations for all five basic attributes. He tested each one and filled three pages of scrap paper with data. He stretched, his joints cracking, and only when his stomach growled with hunger did he remember he had not eaten all day.
He went to the door and picked up the food box Kabuto had left. The food inside had long since gone cold. He did not mind. Grabbing two rice balls, he swallowed them in a few bites. When they stuck in his throat, he picked up the water jug on the table and gulped down a couple of mouthfuls of cold water, then returned to the workbench.
The basic configurations were only groundwork. What he really wanted to make were transitional configurations for attribute conversion.
Everyone in the Shinobi World knew that nature transformation was innate. Most people could only master one or two attributes in their lifetime, and only a handful in the entire Shinobi World could master them all. But to Rinto, attributes were fundamentally just different flow structures of chakra particles. As long as he could find the transitional form between two structures, he could convert attributeless chakra into any attribute, or even convert different attributes into one another.
If this worked, it would completely break down the barriers imposed by a shinobi's talent.
He chose fire and wind first. Their structures were not the most dissimilar, they were highly compatible, and they were less prone to collapse. With a charcoal pencil, he repeatedly sketched the transitional section's patterns on scrap paper, calculating spacing, depth, and changes in chakra flow speed. He went through more than a dozen sheets before settling on the first model.
He picked up a piece of crystal jade, secured it in the vise, took a deep breath, and lowered the blade.
This was far harder than a single-attribute configuration. The fire-attribute structure at the front had to connect to a wind-attribute structure at the back. The transitional section between them had to let the chakra particles smoothly change their spin states, without accumulating or scattering. The slightest error would collapse the entire structure.
He carved extremely slowly. Sweat dripped from his forehead onto the crystal jade, and he wiped it away with his sleeve without ever taking his eyes off the patterns. By the time he finished the last stroke, it was completely dark outside. Only the overhead lamp lit the laboratory, and the surroundings were so quiet that he could hear his own heartbeat.
Rinto removed the crystal jade from the vise. His fingertips trembled slightly, not from exhaustion, but from excitement. He walked to the jutsu-testing target, gripped the crystal jade, and injected his own attributeless chakra into it.
The first half went smoothly. Chakra followed the fire-attribute patterns, and the crystal jade glowed red. But upon reaching the central transitional section, the chakra flow suddenly became chaotic. Particles piled up at a bend and instantly burst through the patterns.
There was a sharp crack.
The crystal jade split straight in half. Flying fragments struck the wall, and one grazed the back of his hand, leaving a small cut. Blood immediately seeped out.
Ignoring the wound, Rinto hurriedly picked up the two halves of crystal jade and held them under the lamp. The fracture was right at the third line in the transitional section, exactly where he had predicted the risk would be.
"The spacing was too narrow," he muttered, picking up the charcoal pencil to make notes. "Fire-attribute particles spin 30% faster than wind-attribute particles. There wasn't enough buffering in the transitional section. Chakra backed up here, and the stress exceeded the crystal jade's tolerance, causing it to fracture."
He felt no frustration. If anything, he was even more excited. Finding the problem brought him one step closer to success.
He immediately redrew the diagram, lengthening the transitional section, adjusting the spacing between the lines, adding two force-dissipating buffer lines, and changing the curvature of the bend. Once finished, he took another fresh piece of crystal jade and resumed carving.
This time, he worked even more slowly, repeatedly checking every line, carving even the depths more precisely than before. By the time he finished, it was well past midnight.
Rinto rubbed his stiff shoulders and walked back to the target, his hand steady around the crystal jade. The instant he injected chakra, the crystal jade first glowed red, then shifted to pale blue-green. The transition was exceptionally smooth, without the slightest hitch.
The next second, a wind blade wreathed in flames shot out and slammed into the steel target with a muffled boom. Not only did the wind blade punch a hole through the plate, but it also scorched a large area around it black, even warping the steel with its heat.
It worked.
Rinto's eyes shone brilliantly. He hurriedly picked up the measuring instrument and checked the data several times. Chakra conversion rate: 87%. No delay in attribute switching. Good structural stability. No risk of disintegration.
Holding the scrap paper, he rapidly recorded the data, his hand trembling slightly. This was not an optimization of a single attribute like before. This completely broke the Shinobi World's established rules. Attributeless chakra converted directly into a compound fire-and-wind attribute. No hand seals, no innate dual-attribute talent. Anyone could use it as long as they had this piece of crystal jade.
"So that's how it works," he murmured, looking at the configuration diagram on the paper. His mind was already considering the next version's improvements, the transition between water and earth, the compatibility of lightning and fire, and even compound structures of three attributes.
"It seems you've made quite a discovery."
Orochimaru's voice suddenly came from the doorway, carrying his usual hiss and a trace of amusement. Rinto turned and only then saw Orochimaru leaning against the doorframe. He had no idea when he had arrived. His golden eyes shone under the light, and he had clearly been standing there for some time.
Rinto showed neither surprise nor displeasure at the interruption. He simply tossed him the crystal jade. "Just got it working. A transitional configuration for fire and wind. Inject attributeless chakra, and it produces Blast Wind Flame directly."
Orochimaru caught it, held the piece of crystal jade between his fingertips, and injected a trace of chakra. Sure enough, flames wrapped around a wind blade instantly took shape. With a casual flick, he sent the wind blade into a pile of scrap iron in the corner, blasting a crater straight into it.
He looked at the crystal jade in his hand, unable to conceal the astonishment in his eyes. He had lived for almost thirty years and seen countless geniuses, but no one had ever done anything like this-turning innate elemental talent into a stone anyone could use. This was no longer improving ninja tools. This was rewriting the rules of ninjutsu.
"Interesting." Orochimaru smiled and tossed the crystal jade back to Rinto. "I thought it would take you at least half a month to grasp the workings of attribute conversion."
"It's quick with samples." Rinto set the crystal jade on the table and picked up the charcoal pencil to keep revising his diagram, without even raising his head. "You're here about the Cursed Seal's buffer configuration?"
"Clever." Orochimaru walked over beside him, his gaze falling on the scrap paper covered in patterns. "I modified the Cursed Seal's structure as you suggested yesterday, but it still doesn't work. The test subjects suffer chakra disturbances before they can last six hours."
Rinto gave a brief acknowledgment, casually pulled out a blank sheet of scrap paper, and began drawing with the charcoal pencil. He had never seen the Cursed Seal's actual structure, so he could only draw a general-purpose buffer model based on Orochimaru's description. It had three layers that dissipated force one after another, allowing the foreign Cursed Seal configuration to gradually embed itself in the human body's chakra structure without a direct collision.
"Your previous Cursed Seal forced the entire structure in at once. Of course that wouldn't work," he said casually as he drew. "Split its configuration into three sections and connect them with this buffer model. Let the test subject's body adapt to the first layer before gradually adding the others. Don't pour it all in at once. Also, smooth away the aggressive structures in the Cursed Seal. The more rounded, the better. Otherwise, even if it embeds successfully, it'll slowly corrode the host's chakra structure."
He drew quickly, his lines crooked, yet every stroke addressed the issue. Once finished, he pushed the paper toward Orochimaru and turned back to his own transitional configuration diagram, as though what he had just explained were something too trivial to mention.
Orochimaru picked up the sheet and stared at the three-layer buffer model for a full minute. The dead end he had spent a year trapped in had been broken open by a few casual strokes from this boy.
"Thanks." Orochimaru offered a rare word of gratitude, folded the paper, and put it away. "Tell Kabuto directly if you need anything. Even if Konoha doesn't have it, I can get it for you."
"Mm." Rinto answered, already picking up a fresh piece of crystal jade to carve a water-and-earth transitional configuration, paying him no further attention.
Orochimaru did not disturb him any longer and turned to leave. He knew very well that choosing to work with Rinto was the best decision he had ever made. What this unremarkable-looking youth had in his head was more astonishing than all the Shinobi World's ninjutsu research combined.
The laboratory fell silent again.
Rinto completely lost track of time and forgot that he had already been awake for almost two days and a night. The carving knife in his hand never stopped. The pile of ruined crystal jade grew larger, and the stack of scrap paper on the table grew higher.
When dawn came again, he finally completed the water-and-earth transitional configuration too. Looking at the crystal jade in his hand, he injected chakra, directly producing Lava Release's corrosive fluid, which melted a deep pit into the steel target. Only then did the corner of his mouth give a rare twitch, revealing a hint of a smile.
It was not about power, nor about being able to slap anyone in the face. It was simply the satisfaction of solving a difficult problem.
He placed the two successful pieces of crystal jade in a box, then took out the two Ice Release chakra samples. Previously, he had only dared to deduce the structures of dual-attribute Kekkei Genkai in theory. Now that he had actual samples, he could finally verify his model.
When Kabuto brought breakfast, he found Rinto hunched over the table, studying the samples in the glass tubes and frantically calculating something on scrap paper. A small heap of ruined crystal jade lay on the floor. The food box by the door remained untouched.
He shook his head, put down the new food box, took away the old one, and quietly withdrew without daring to make a sound.
No one in all of Konoha knew that, in this laboratory beneath the Hokage Building, a member of an Uchiha branch family who was regarded as trash was gradually dismantling rules passed down in the Shinobi World for over a century. Rinto himself was not thinking that far ahead, either.
He only wanted to understand the essence of chakra a little more thoroughly.