Rinto was woken by a tug on stuck gauze.
The scab on the back of his hand had seeped blood, which had dried and stuck to the coat brushing against it. Any movement pulled at it with piercing pain. He swore, "Fuck," and jerked his hand back. The scab tore straight open, and beads of blood welled up instantly. That woke him completely. His stiff neck was even worse now, rigid as a rock. He could only move with his neck straight; the slightest tilt made him bare his teeth in pain.
It had long since grown light. Morning sunlight slipped through the vent, casting long, narrow shadows across the floor. The desk lamp had burned all night, and even the bulb was hot. The desk and floor were still a mess. Ruined starfall iron lay scattered everywhere, and discarded sketches covered half the room. He had slept slumped in the chair for almost a day. Every bone in his body felt stiff, cracking whenever he moved.
He pushed himself up against the desk, his legs so numb he nearly dropped to his knees. He held on to the edge for a long while before shuffling to the corner to find water. The insulated jug Kabuto had left earlier was still there, its water completely cold. He hugged it and gulped down more than half its contents. The cold made his stomach cramp before the dry ache in his throat finally eased.
Beside the jug sat the rice balls Kabuto had brought, still wrapped in plastic and long since hardened. He squeezed them, then casually tossed them back into the trash bag. He had no appetite. Looking up, he immediately spotted the scrap iron on the desk that he had ruined with his modifications. Yesterday's frustration at making things worse with every change surged back. He clicked his tongue, turned away rather than look at it, and began rummaging through the discarded notebooks piled haphazardly on the materials rack.
Not doing this anymore. What a pain.
He was not looking for anything in particular. He simply did not want to touch that three-attribute mess, so he started sorting through the junk he had accumulated over the past dozen-odd years. Notebook after notebook of discarded drafts, from the Wind Release configurations he had first drawn in a shabby wooden hut, to dozens of rejected Senjutsu solidification diagrams, to records of Hashirama Cells experiments. Some pages were yellow, others creased; some had been soaked in water, others scorched black by chakra. Still others were covered in curses he had scribbled down after blowing up materials back then.
He crouched on the floor, leafing through them one by one. Whenever he came across something funny, he snorted and cursed his younger self for being out of his mind. Eventually, he dug out a hardcover notebook he had bought with three months of savings when he first arrived in Konoha. It was filled with basic chakra channel configurations. On one page, he had circled a corner in red and written a crooked line beside it: Corner too sharp, catches chakra. Change to curved surface for smooth flow.
It was a pitfall he had encountered when he first started working on solidification. That corner had cost him more than a dozen pieces of darksteel. Only after he replaced the right-angled channel with a gentle curve had he resolved the problem of residue getting stuck.
Rinto's movements came to a halt.
Holding the notebook, he stared at that line for a long while. Until now, he had been fixated on adding anchor points and trailing extensions to clear residue out of the corners. But the root problem was that the corner itself was a dead spot! No matter how clever an anchor point's trailing extension was, it could not hook out the fragments in a right-angled crevice. He might as well change the corners directly, replacing every right-angled channel with a gentle curve so the chakra itself flowed smoothly. With no dead spots left at all, there would naturally be no residue.
He had kept thinking the channel structure was fixed, and changing it would affect the rhythm of anchor-point reconstruction. But Shukaku's chakra configuration had no sharp corners at all, only smooth curves. There were no breaks in the chakra's circulation, so naturally there was no residue.
"Fuck. Went around in a huge circle and actually forgot the basics." Cursing himself, he tossed the notebook onto the floor, lunged back to the desk, grabbed a charcoal pencil, and started drawing.
Previously, all the main channels had right-angle turns to save space. Now he changed every one to a gentle curve, arranging even the anchor points along those curves. During reconstruction, the chakra would follow the curves without trapping residue in the corners. He did not even need to add trailing anchor points, simplifying the structure instead.
The longer he drew, the more smoothly it went. The knot that had held him up for almost a week had actually loosened just like that. He had kept trying to patch the existing structure, forgetting to change it at the root. The more he patched, the messier it became; the more he modified, the more it exploded.
While he was absorbed in drawing, two soft knocks sounded at the door. Kabuto pushed it open and poked his head inside, a scroll in his hand, his footsteps very light.
"Mr. Rinto, sorry to disturb you," Kabuto said quietly. "I've put the filtration configuration you modified for me last time to use. It works extremely well, so I came specifically to thank you. Also, Lord Orochimaru asked me to tell you that the high-purity force-conducting crystals you mentioned earlier have arrived from Sunagakure. Would you like to collect them now, or should I bring them over?"
Rinto did not even look up. His pencil raced across the paper as he casually replied, "Just leave them here."
"All right." Kabuto hurriedly set the box containing the crystal jade at the edge of the desk, then placed the insulated food container he was carrying in the corner. "I brought you hot noodle soup. Freshly served, still nice and hot." He paused, then mentioned in passing, "Lord Orochimaru's men drove away the Anbu at the entrance today. But I hear the Hokage Tower hasn't given up. Apparently, they're negotiating with him to transfer you to the Anbu's ninja tool unit."
Rinto's pencil paused, and his brows instantly drew together. His voice was full of anger. "They can keep dreaming. If anyone else comes to bother me, I'll cut them down. Orochimaru can deal with the consequences himself."
"Understood. Lord Orochimaru has already turned them down, saying your research is classified and they aren't allowed to interfere." Kabuto hurriedly acknowledged him, then quietly added something about his own work. "There are still some problems with the Cursed Seal configuration I modified earlier. It collapses as soon as senjutsu chakra enters it. If you have time, could you take a quick look for me? Just at the structure. It won't take much of your time."
"Leave it there." Rinto still did not look up, his pencil never stopping. "I'll look when I have time."
"Ah, all right. Thank you." Kabuto hurriedly set his drawings at the edge of the desk, then crouched down and stacked the discarded notebooks Rinto had dug out, placing them on the rack one by one. He swept up the fragments and scrap paper covering the floor, moving softly and making no further noise to disturb him. Once he finished, he withdrew, closing the door without so much as a sound.
After Kabuto left, Rinto finished drawing the new channel structure. He did not rush to engrave it. He studied the plans for a long while, then adjusted two anchor points, arranging them along the curves so reconstruction would run more smoothly without catching. Only after making those changes did he grab a fresh piece of starfall iron and click it into the vise.
He was especially careful as he set his engraving knife to it. The curvature of the channels had to be exact. The slightest error would throw off the flow rate, and the anchor points had to be adjusted to match the curves. He had overturned the entire previous structure; it was effectively a whole new set of engravings. His neck was still stiff and would not tilt, so he could only lean his whole body forward, his face almost pressed against the vise. His eyes were bloodshot from staying up, but the hand holding the knife remained perfectly steady.
He engraved one anchor point in the wrong position, swore, "Fuck," and threw the iron away outright, starting over with a fresh piece. When his hand went numb partway through, he shook it out for a long while. The cracks in his fingertips pulled painfully, but he did not stop, gritting his teeth and continuing to engrave. By the time he finished the last stroke, the sky outside was completely dark. The desk lamp cast a cold white reflection across the starfall iron.
He removed the iron, worked his neck, which was so stiff it felt ready to snap, took a deep breath, and walked to the steel plate target to inject chakra.
Lava Release. Acid sprayed out steadily, and white smoke hissed from the thick steel plate. Chakra circulated along the gently curved channels without the slightest obstruction.
He switched to Explosion Release. The anchor points reconstructed instantly, and a shock wave slammed into the steel plate. No stalling, no residue.
He switched again to Lightning Release. Lightning struck the steel plate, carving deep gashes into it. The iron only grew slightly warm.
Rinto's heartbeat quickened a little. He began switching continuously: Lava Release → Explosion Release → Lightning Release → Lava Release, faster each time, back and forth. After a full hundred switches, the starfall iron in his hand was merely warm. It had neither overheated nor cracked. Holding the channels up to the light, he found them perfectly clean, without a trace of residue.
It worked.
The problem that had held him up for almost a week was solved just like that. Not through some exquisitely clever anchor-point design, but by changing the most basic channels and eliminating the dead spots at their root.
Holding the iron, he stared blankly for two seconds, then tossed it onto the desk and let out a long breath of relief. All the strength drained from his body. He slumped in the chair, eyes closed, breathing hard for a long while. Only after recovering did he remember the noodle soup Kabuto had brought. He shuffled over and opened it. The noodles had long since clumped together, and the soup was cold. He did not care. Picking up the bowl, he shoveled down more than half. Cold soup poured into his stomach, and it finally stopped feeling empty.
After eating, he pushed the bowl aside and sat back at the desk, staring blankly at the plans he had just drawn. Three attributes worked. What about four? Add Earth Release, for instance? Or Wind Release? Could four completely different attributes switch seamlessly within the same carrier?
As soon as that thought emerged, most of his exhaustion vanished. He grabbed a fresh sheet of scrap paper, but just as he was about to draw, he frowned again. Gently curved channels could solve the circulation problem for three attributes. But with four, the number of anchor points would have to double, and the logic of reconstruction would be more complicated. A single anchor point would have to accommodate four completely different attribute structures, leaving less room for error. The slightest carelessness would cause a blowout.
Moreover, the chakra properties of the four attributes were completely different. Water and earth were fluid, fire and wind were explosive, lightning was sharp, and earth was heavy. Making the same set of channels and anchor points accommodate four entirely conflicting chakra flows would be more than twice as difficult as handling three attributes.
Biting the end of his pencil, he scribbled aimlessly on the paper and drew a four-anchor-point structure. The moment he finished, he shook his head. No. Too many anchor points. The channels would be too crowded, and the chakra flows would interfere with one another. He drew a more compatible core anchor point, but the more he drew, the less right it felt. A core anchor point bearing the reconstruction of four attributes would face too great a load and could easily shatter outright.
No matter how much he drew, he could not find a single workable approach. Growing increasingly irritated, he tossed down the pencil, leaned back in his chair, and closed his eyes. His mind was filled with the chakra characteristics of the four attributes, circling endlessly without a single loose end he could connect them with.
The sky outside slowly brightened again. He remained in the chair, sometimes grabbing his pencil to sketch a few strokes, sometimes crumpling up the paper and throwing it away. He spent the entire night at it without producing a usable framework.
When daylight filled the room, he threw down his pencil and cursed, "Fuck, my brain's stopped working," then stopped forcing himself. He stood, shoved the plans on the desk haphazardly aside, and locked the successful piece of three-attribute starfall iron in the blastproof cabinet. Then he picked up the drawings Kabuto had left at the edge of the desk, squinted over them briefly, casually made a couple of corrections, and tossed them back onto the edge.
After that, he did not touch his engraving knife or draw any more plans. He leaned back in the chair, pulled his coat around himself, and closed his eyes. He had only meant to doze for ten minutes, but his eyelids grew heavy, and he fell straight asleep. His neck was still stiff, leaving him propped rigidly against the chair as his breathing slowly deepened.
The laboratory was silent. Only the breeze blowing through the vent stirred the loose sheets of scrap paper on the desk. The scrap iron and discarded paper covering the floor lay quietly in the morning light. He did not wake, his brows still faintly furrowed, as though he were still wrestling with four-attribute anchor points in his dreams.