Time flew by, and before long it was May. Cherry blossoms still fluttered along the roads, though the weather was already turning hot.
Everyone seemed busier than ever.
The higher-ups remained lukewarm in their approach. Confident they had Sōjun Minamoto in their pocket, they kept sending new people every few days to try and win him over—yet never offered anything of substance.
Eventually, it was Utahime Iori and Mei Mei who came to visit, followed still by the trio who hadn't given up—people with at least some connection to Sōjun.
Even Riko Amanai, newly enrolled, wasn't spared.
She showed strong potential, and Shoko Ieiri believed she might be able to master the Reverse Cursed Technique. Lately, Shoko had kept her close, teaching her healing hand-in-hand.
She was also one of the only two people who genuinely and urgently hoped Sōjun would join the medical team.
So she started pestering him daily—pleading, coaxing, persuading, baiting—she tried everything. None of it worked. Riko would glare at him in frustration, standing by his side.
You really are immune to pressure.
Sōjun glanced at her. He actually cared a bit about these few people.
Immune to pressure?
If that were true, why would he keep teaching her Jujutsu? Even now, Riko Amanai would regularly seek him out for lessons on curses—and not once had he turned her away.
She could tell he wouldn't give in, so she stopped pushing and just visited more often under the pretense of training.
The last to show up was Shiko Mishima. She wandered the living room a few times, then left. From what Sōjun knew of her...
She was just going through the motions.
The higher-ups had started playing the emotional card—and that annoyed him. There were always people who thought a few well-placed words could make others abandon their morals, friendships, even family, just to work blindly for them.
That kind of arrogance was infuriating.
Sōjun was running out of patience. His condition had always been clear:
He was willing to join the medical team—but only if he had full autonomy. Who he treated, how he treated them, when he treated them—that would be up to him. He didn't want anyone constantly trying to dictate how he worked.
His request was simple. It involved no benefits or hidden demands. But to the higher-ups, it was seen as defiance—something they simply couldn't tolerate.
So Sōjun dropped everything else and entered seclusion. His time was far too valuable to waste on this.
A Fly Head materialized in front of him.
After the Tengen incident, a thought had taken root in Sōjun's mind.
What would happen if he combined his Innate Technique, Barrier Techniques, and Cloning Technique?
He hadn't even started testing it yet, and already he was feeling a rush of excitement.
Up until now, anything he assimilated had to maintain physical contact to remain stable—otherwise it would fall apart.
He'd gotten used to using strands of hair as anchors, but over time, that method felt increasingly inconvenient.
Why was it that the clones produced by his Cloning Technique could act independently after assimilation, while the cursed spirits or physical clones he created still required constant contact?
He wanted to break that limitation.
His first thought was Puppet Manipulation.
Then he thought of Cursed Corpses.
Masamichi Yaga, the leading expert in Puppet Cursed Techniques, controlled his Cursed Corpses without any physical links—using a special method.
Sōjun had asked him about it. Yaga said the key was the core.
Artificial Cursed Corpses had a heart-like core. That core was what enabled remote control.
But Sōjun couldn't create those himself, and he didn't quite understand why.
If he had to find someone else with Puppet Techniques just to assimilate them, it would be no different from using his Cloning Technique.
Borrow wood to fix a window. Borrow a saw to cut the wood. Then owe a favor just to borrow the saw...
It all just spiraled. Wasn't that overcomplicating everything?
Sōjun Minamoto's principles wouldn't waver over something like this.
Can't use your own technique? Of course he could—he just hadn't found the right approach yet. He had absolute confidence in his technique.
After assisting Tengen's evolution, Sōjun Minamoto had a fresh spark of inspiration. A connection didn't have to be something physical. Cursed Energy worked. So did the soul. Even a barrier could suffice.
With the addition of the flesh armor, and the Barrier Anchor Dart boosting perception further, the sensation of instantly perceiving every passing thought was incredible.
A Barrier Anchor Dart sprouted from his forearm, and in that moment, the world snapped into sharp focus.
He plucked out an eyeball, tore off a fragment of his soul, and poured Cursed Energy into his hand. The three fused—crimson, blue, and black blending in equal parts, aligned by a specific structure. From that, a dense, dark purple gas-liquid mass formed.
Sōjun Minamoto studied the substance carefully. It felt too light, too unstable—like it would drift away the moment he let go.
It needed weight.
He headed to the forge and began sorting through metals. The material needed to be right—not too dominant, but with the proper properties and weight.
An eyeball weighed about 7 grams. One portion each of flesh, soul, and seven portions of Cursed Energy added up to around 21 grams. The metal couldn't overpower this mixture and still had to bring certain qualities.
Lead was highly absorbent. Copper and iron were often used in the Jujutsu world to ward off evil or neutralize toxins. Mercury sulfide—cinnabar—was excellent for conducting Cursed Energy and commonly used in talisman inscriptions.
Sōjun Minamoto mixed the metals into the correct ratio, ground them into powder, and added it to the dark purple gas-liquid blend.
After a brief wait, the mixture began to solidify, forming a sphere with the size and look of an egg. Its color shifted—faint gold first, then deepened gradually.
Using cinnabar, Sōjun Minamoto etched a soul-bound barrier onto the sphere's surface—the same technique used to sustain Tengen's soul.
Crimson lines flickered faintly, then vanished beneath the golden hue.
The sphere began to pulse gently, like a heartbeat. Its surface smoothed into a seamless, perfect orb.
He released it. The sphere floated in midair, still under his perfect control.
Retracting the Barrier Anchor Dart, the sphere dipped, faltered, then stabilized and floated back up again.
It worked.
Sōjun Minamoto stepped out of the forge and summoned the Fly Head, feeding the sphere into its mirrored core.
Through his perception, he tracked the sphere as it descended, settling behind Fly Heads' navel. Like a seed taking root, it sprouted thick red veins that spread rapidly, anchoring into place.
Soon, blood-red lines emerged on Fly Heads' surface, both pairs of wings streaked with crimson. A faint red glow shimmered with each breath, waxing and waning.
Sōjun Minamoto tentatively retracted the hair attached to the Fly Heads' head.
Its body showed no signs of collapse. It floated steadily, wings quivering slightly.
It mimed grasping the air, then began circling Sōjun Minamoto with smooth, fluid motions...
All under Sōjun Minamoto's direct control.
Finally free of the hair tether, they were now linked purely through thought.
As he executed the perfected technique, the Fly Head transformed slightly again. Its wing structure adjusted, color shifting from pale gray to a pure white. With a flawless body and mirror-like dignity, it now carried an almost divine aura.
Within Sōjun Minamoto's mental domain, the Fly Heads' image appeared as well.
Now, they were truly one and the same.
Sōjun Minamoto released control, and the Fly Head instantly reverted to its usual dumb, cocky self.
He burst out laughing.
Swallow this golden elixir, and your fate belongs to me—not the heavens.
Let's call it "Golden Core."
It fit perfectly with his long-held beliefs. As expected, his technique was the strongest.
Master one path, and all others follow. As long as you find the right approach, nothing is impossible.
Just like with the original Puppet Manipulation Technique—he once needed hair as strings, but now, that limitation was gone.
If people are made of cells, then Sōjun Minamoto now consisted of himself and the Fly Head. The Fly Head was like a detached limb—a hand, a leg—existing outside the body, yet still part of him.
Looking at the Fly Head, Sōjun Minamoto was pleased.
Phase One of the Golden Core construction theory—complete.