Sukuna walked barefoot across the wet grass and the rain hit his shoulders and ran down the black tattoos on his arms and chest and disappeared into the waistband of his training trousers. The clearing sat three kilometers east of the compound, past the old growth cedars and across a stream that never warmed up, and he'd claimed it during their first year with the Akatsuki and cleared it by hand and by technique until it measured forty meters across. He came here every morning before dawn. The canopy caught most of the rain but not all of it, and the drops that made it through landed cold against his skin.
He was sixteen, and the years with the Akatsuki had added height and breadth and a solidity to his frame. His shoulders had widened and his jaw had squared and the muscles along his arms and torso had thickened into something dense and functional. The Spider Sage's contract markings had grown with him, keeping their proportions across his expanding skin, and the geometric web patterns caught the gray morning light in faint iridescent flashes when he moved.
Sukuna stopped at the clearing's center and stood with his feet apart and his arms loose at his sides and his breathing measured through his nose. He closed his eyes and turned his attention inward and felt his chakra network laid out beneath his awareness.
His reserves sat heavy and dense in his core. Years of meditation and combat and whatever his first Negative Chakra production had done to his pathways had expanded his capacity by orders of magnitude, and the recovery rate had climbed alongside it.
He opened his eyes and raised his right hand in the cutting gesture.
"Dismantle."
The invisible slash erupted from his fingers and crossed forty meters in the blink of an eye and struck a cedar at the clearing's far edge. The wood split with a crack that scattered birds from the surrounding canopy, and the tree's upper half tilted and fell sideways in a cascade of breaking branches and dislodged water. Sukuna lowered his hand and checked his reserves. The expenditure barely registered; his recovery rate would erase it within seconds.
He raised his hand again and released a second Dismantle at the stump. The slash cut through the remaining trunk at ground level and the wood separated cleanly and toppled backward into the undergrowth. A third Dismantle followed ten seconds after the first, aimed at a boulder twenty meters to the left, and the stone split along the cutting plane and the two halves fell apart with a grinding sound that vibrated through the wet earth. A fourth struck another tree. A fifth took a branch from a cedar on the opposite side of the clearing.
Ten seconds between each release, and his reserves held steady.
Cleave required a different approach. Sukuna shifted his stance and focused on the remaining boulder fragments, gathering chakra into a pattern that adjusted itself automatically to the target's properties. Cleave read the target's durability and scaled its cutting force to match, which made it redundant against unprotected flesh and bone but devastating against enemies who shielded themselves with defensive jutsu or channeled chakra to harden their tissue. The technique found its value in the gap between what Dismantle could cut through effortlessly and what required calibrated force to penetrate, and that gap grew wider as the opponents grew stronger.
He released Cleave at the largest boulder fragment. The cutting force struck the stone and adjusted mid-contact, reading the material's resistance and increasing its output until the stone yielded. The fragment split into three pieces that tumbled across the grass and came to rest against the base of a standing tree. The chakra cost sat higher than Dismantle's flat rate because the adjustment process consumed additional energy proportional to the target's durability, and against a shinobi using chakra-reinforced defense the cost would climb further, and against someone channeling a full body-enhancement technique, further still. The scaling was the advantage and the problem both, and the thinking remained the same as it had always been: Dismantle for the vulnerable, Cleave for the armored.
Kamino came next.
Sukuna raised his right palm and let the conversion begin. His chakra traveled through the pathways from core to extremity and shifted states as it moved, transitioning from the balanced warmth of standard chakra into searing heat. The flames gathered in his palm, white at the center, graduating outward through yellow and orange and deep red at the edges, and the air around his hand rippled with distortion. The compression happened naturally now, the arrow shape forming through muscle memory, and the dense projectile of concentrated fire sat in his palm and waited.
He launched it at the tree line.
The flame arrow crossed the clearing in a streak and struck a fallen trunk at the far edge and detonated. The wood blew apart in a sphere of superheated fragments that set three adjacent trees on fire before the rain started suppressing the flames. The explosion echoed off the hills and rolled through the forest, and when the sound faded the clearing smelled of charred wood and ozone and burning pine resin.
Sukuna checked his reserves. The cost had dropped over the years as his efficiency improved and his capacity grew, and the technique that had once consumed a quarter of his total reserves now sat closer to a tenth. He could throw Kamino far more freely than before, multiple times in a single engagement without serious concern.
He moved to the center of the clearing and bit his thumb. The blood came quick and warm, and he formed the modified clone seals and pressed his bloodied palm to the earth and let his chakra pour outward.
Red smoke erupted across the clearing in rolling waves that carried the copper scent of blood and fresh tissue. The smoke cleared in stages, and within thirty seconds the clearing held fifty-three bodies that breathed and blinked and stood on the wet grass with awareness behind their borrowed eyes. Sukuna felt the connection to each one, fifty-three threads of consciousness branching from his own awareness.
The majority were basic constructs. Functional bodies with rudimentary chakra networks, capable of physical combat and surface adhesion and basic enhancement, but lacking the refined pathways necessary for complex techniques. They could bleed and sustain damage and fight and die like real people, and they could follow instructions and adapt to changing circumstances, and their value as expendable combatants hadn't diminished.
Ten of the fifty-three were different. Their chakra networks were denser and more complete, built with additional investment of Sukuna's own cells and energy during the creation process. They could mold chakra with enough sophistication to perform standard ninjutsu, could shape elemental techniques and maintain Body Flicker and create basic genjutsu disruptions. They couldn't perform Dismantle or Cleave or Kamino, because those techniques required the specific architecture of Sukuna's personal network, but they could fight at a level that would challenge most chunin and give a tokubetsu jonin something to think about.
Sukuna dispersed the clones with a thought and felt the chakra return in a rush. The reabsorption efficiency had improved alongside everything else, and the loss during conversion sat at maybe fifteen percent now compared to the thirty percent he'd accepted during the early experiments.
He walked to the clearing's western edge where the ground rose into a low hill, and he began running.
His feet carried him up the slope and into the trees, each step finding purchase through adhesion his body maintained without conscious thought. The Body Flicker variants were automatic now, the same way his lungs breathed and his heart beat, which meant he could think about other things.
He reached the ridgeline above the clearing and kept running. The trees thinned as the elevation climbed, and the ground became rocky and uneven, and Sukuna's feet transitioned from bark to stone without a change in rhythm. At the ridge's peak the land dropped away into a steep ravine, and the far side sat thirty meters distant across open air.
Sukuna's right foot left the stone at the edge.
His chakra compressed the air beneath his sole in a burst that created a momentary platform, and his weight settled onto the compressed gas for the fraction of a second it took to push off and drive his left foot forward. The second step found its own platform, the chakra firing and compressing and holding and releasing in a sequence his body had learned through years of stubborn practice. Each step lasted maybe a quarter of a second before the compression failed and the air became air again, and each step demanded a precise output of chakra at a precise timing that left almost no margin for error.
He crossed the ravine in nine steps, his body rising and falling in a shallow arc that peaked at the midpoint and descended toward the far side. The ninth step brought his foot down on solid stone, and he landed in a stride that carried him forward into the trees on the opposite ridge without breaking pace.
Air walking remained difficult. The chakra cost per step exceeded any other form of locomotion he possessed, and sustaining it for extended distances would drain him at a rate that made it impractical for anything beyond short tactical applications. He could cross gaps and gain elevation and reposition himself in three-dimensional space with a freedom that ground-bound fighters couldn't match, but he couldn't fly. Not yet, anyway.
Sukuna circled back toward the clearing along a path that took him through the dense forest south of the compound. His pace slowed. He'd been thinking about Domain Expansion for years now, and the answer still wouldn't come.
He stopped on a thick branch overlooking a natural basin where rainwater had collected into a shallow pool. The surface caught the gray sky and held it in a flat reflection that trembled with each falling drop. Sukuna crouched there and rested his forearms on his knees and stared at the water.
Cursed energy didn't exist in this world. Chakra operated on different principles. And every attempt to construct a domain through fuinjutsu had stalled at the point where barrier mechanics and targeting functions tried to operate in the same sealed space. The barrier needed static and sustained output to hold together, and the targeting needed dynamic output that could follow the target. The two just didn't work in the same system, and that had resisted every workaround he'd devised.
But Negative Chakra had changed the equation.
Sukuna pulled the physical and spiritual energies apart inside his network and held them there. The two components strained against each other in the familiar tension that produced the cold and colorless energy he'd discovered on a forest floor with his arteries open and his brother dying beside him. The Negative Chakra settled into his palms and the grass beneath his branch went brown.
The separation was the key. Domain Expansion required the manipulation of mental energy in its raw form, the spiritual component stripped free of its physical counterpart and wielded directly. The domain was a mental construct forced into the physical world, and the mechanism that accomplished that had to operate through pure spiritual energy. Because spiritual energy was the substance of will and consciousness and the interior landscape the domain was supposed to represent.
The problem was that pure spiritual energy couldn't be emitted from the body.
Sukuna released the separation and let his chakra recombine, and the cold faded and the dead grass stayed dead. He'd tried dozens of times to isolate the spiritual component and project it outward. Every attempt produced the same result. The energy just dispersed. It was formless in a way that physical energy was not; physical energy had mass and momentum and interacted with the material world through properties the material world understood. Spiritual energy was just information, with nothing physical to hold onto, and the moment it left the network that generated it there was nothing outside the body that could maintain its shape.
So it needed to be combined with something. But combining it with physical energy just produced chakra again, which was the starting point rather than the destination. The circular logic of this particular problem had been chasing itself around in his head for longer than he cared to admit.
He needed a third component, a third kind of energy that could carry spiritual energy without converting it back into standard chakra, something that existed outside the body and could hold the shape long enough to build the domain.
Sukuna stared at the rain falling into the pool below and watched the ripples spread and intersect.
Natural energy was a possibility; the ambient energy that permeated the world itself, distinct from the chakra that living beings produced internally, a life force that ran through everything from the smallest insect to the oldest mountain. He'd sensed it during meditation, a vast and diffuse presence that surrounded his own network the way the ocean surrounded a swimmer. Sages could absorb natural energy and balance it with their own physical and spiritual energies to produce something called Sage Mode, a transformation that dramatically increased their capabilities. But Sage Mode was just another form of combination, and the mathematics of combining natural energy with isolated spiritual energy were entirely unknown.
It might work, or it might not. He wouldn't know until he tried, and trying required access to natural energy in quantities sufficient for experimentation, which meant either finding a sage willing to teach the absorption technique or figuring it out independently.
The theory felt right, though. It had the shape of a solution even if the details were still unclear. And the sensation of being close... that was something, at least.
Sukuna straightened on the branch and rolled his shoulders. His body was warm from the training and the rain was cold against his skin and the clearing below held the evidence of his morning's work in fallen trees and split boulders and scorched earth. He should head back. The compound would be waking up and Wasuke would be looking for him.
A presence appeared at the edge of his perception.
Sukuna turned his head and found Nagato standing on a branch twenty meters to his left, his dark cloak soaked through and his red hair plastered against his face and those ringed eyes catching the gray light. Nagato had arrived without sound, without detectable chakra fluctuation, moving through the forest with the ease of someone who'd spent his entire life in it.
He watched Sukuna for a moment, and he looked both excited and serious.
"Hanzo-sama has sent a summons," Nagato said. "He wants Yahiko, Konan, and me to attend a summit at his compound. Konohagakure, Sunagakure, and Iwagakure have agreed to send delegations, and Hanzo has proposed the Akatsuki as neutral mediators for the peace negotiations."
Sukuna let that sit for a second.
"Neat," he said. "Looks like we’re finally important."
Nagato nodded and shifted his weight on the branch, and the wood creaked beneath him. "Hanzo-sama believes the current ceasefire is fragile enough that formal mediation could prevent the next conflict before it starts. He cited our reconstruction work and our neutrality as qualifications, and our goal of advocating for peace. The delegations have apparently agreed to the terms."
Sukuna looked at Nagato's face. The hope was genuine, and so was the weight of it.
"When?" Sukuna asked.
"Three days. Yahiko and Konan are already preparing." Nagato paused, and those ringed eyes searched Sukuna's face. "Yahiko wants you and Wasuke to remain at the compound while we're away. Security coordination and operational continuity. He trusts you both to hold things together."
Sukuna nodded once, and Nagato accepted the gesture and turned and dropped from the branch and disappeared into the forest, his dark cloak blending with the shadows between the cedars until he was gone.
Sukuna stayed on his branch and listened to the rain.
His gut told him something about this was wrong.