Shien was still flush from his seventh birthday celebration two weeks ago. Shien had gone to Tokyo Disneyland with his mother, Mai and Maki. Chujuro had accompanied them to keep Shien safe but he knew to stay out of sight and not ruin Shien's good time. Shien was walking through the yard as the Kukuru unit was training.
Shien had spent the last year refining his curse technique. A sorcerer's output was as important as his cursed energy reserves, and Shien despite his massive cursed energy reserves had an output equally as large. He could empty his reserves if he was inefficient or wasteful with his curse technique, which meant raw destructive power alone was meaningless unless he could shape it into something precise.
Detonation had started as a simple trigger, a snap followed by purple fire, but Shien had forced it into categories the same way barrier techniques were divided into rules and conditions. His right hand was precision, targeted detonations of his curse energy placed at specific points. His left hand was punishment, the same phenomenon pushed through higher output, the kind that produced overwhelming heat and pressure, but more indiscriminate attacks reserved for situations that did not call from much restraint or when he did not have to worry about collateral damage.
Then came the refinement that mattered most: turning Detonation into a guaranteed-hit technique without building a domain. Shien learned that cursed energy traveled with intent, and that contact reduced loss of efficiency, because there was no air to bleed power into and no distance to distort the shape. If Shien placed his palm on a target, he could detonate his cursed energy directly through contact, producing destroying the object or person with precisely the amount of curse energy required. The technique adjusted according to resistance, automatically increasing output against tougher cursed reinforcement and reducing output against weaker targets, so it never wasted cursed energy and never failed due to underestimating durability. Shien didn't have to guess how much power to use; the cursed energy did the calculation for him as it met the target, the detonation becoming exactly as strong as needed and no stronger. He named that refinement Cremation.
Even his feet had become triggers. A stomp sent detonation outward in every direction at ground level, a controlled wave of force and heat meant to destroy and punish anyone who tried to surround him. It was less efficient than the precision of his right hand and less absolute than the destruction of his left, but it controlled space, and controlling space was essential when fighting multiple opponents.
Shien continued walking, eyes already looking ahead. He was on his way to learn domain techniques from Naobito and Ogi. The Zenin elders were scrambling to keep him occupied and failing miserably. Shien was learning far faster than anyone expected, and Shien was eager to get stronger. The faster he learned, the more freedom he could win for both himself and his mother. Even now, Shien heard how they called him a future Special Grade.
Special Grade was the highest possible rank a sorcerer could achieve. It was reserved for those beyond jujutsu society's comprehension of what a sorcerer should be capable of. A Special Grade sorcerer was someone who could take over a country. Shien was not someone who overestimated himself. The memories of his past life, although poor at conveying emotion, were very effective at transmitting wisdom. Afterall memory without emotion was like sucking on a lolipop with the wrapper on . Shien could simply not understand the context of what was happening as despite his serum enhance intelligence he was still a child .
It is far better to be a guy with an IQ of 130 who thinks it's 100 than a guy who has an IQ of 130 but thinks it's 150.
Shien needed his clan as much as it pained him to admit it. The Kukuru unit paused their training to bow as he passed through. A normal person would not have heard the head of the Kukuru unit mumble "whore's son" beneath his breath, but Shien's enhanced senses picked it up.
Shien stopped in his tracks, and his cursed energy slipped loose. Nobuaki Zenin was one of Naoya's supporters.
Since Shien's rapid ascent in power and favor in the eyes of the clan head, the clan had started to pick sides on who they would support as successor. Shien cared about the safety of his mother rather than these groveling lickspittles. When Shien reached his full potential, these insignificant squabbles would mean absolutely nothing. But this disgusting subhuman mongrel with no cursed technique had called his mother a whore—the sweetest, kindest woman in his life, the only woman who loved him unconditionally. Insulting his mother was a popular way for his detractors to discredit him, as he was the son of a concubine, and despite his immense cursed energy reserves and powerful technique, that still mattered to some idiots. Shien could not let that slide. Young he may be, but he was not foolish.
He turned around and directed his ire at the person who was foolish enough to insult his mother. Shien snapped the fingers on his right hand; a snap echoed across the training field as Nobuaki Zeinin screamed, clutching his mouth as purple flames spurted through his nose. Nobuaki rolled on the floor with a dry, rasping sound. Shien had burned his tongue and most of his throat and lungs. There were more than thirty people in the Kukuru unit, yet none of them moved to help their leader. Rooted to their spots in pure terror, hoping not to draw attention from Shien.
Nobuaki was writhing on the hard-packed dirt, trying to breathe through his ruined lungs as Shien walked towards him, stomping on his knee. The crack of bone could be heard around the courtyard. There were no shouts of protest, just stunned silence. Shien was enjoying the terror in Nobuaki's eyes as he gasped for breath, trying desperately but unable to. Shien could have incinerated him into nothing, but he wanted to make an example out of this idiot who dared to have opinions. Shien looked into Nobuaki's pleading eyes and snapped again, just strong enough to melt his eyeballs but not enough to burn his brain to a crisp. After all, Shien's cursed energy control was nigh perfect after all the grueling training, and he wanted this idiot to regret ever saying those stupid words before dying.
The commotion had drawn the few members of the Hei who were there within the dojo to come out. Chujuro, Jinichi and Ogi stepped out, their eyes searching the yard before locking onto Nobuaki's writhing body and Shien looking at him with mild curiosity. Naobito staggered out, wiping his sake-stained mouth with his sleeve, realizing the dire situation. "Oi!! Stop! No more fighting," he said, trying not to slur the words and maintain his authority.
"Papa! Good morning! I was simply burning some trash! I hope you don't mind." Shien said with a bright, cheery attitude. Before another snap engulfed Nobuaki in purple flames, reducing him to ashes. The members of the Hei looked aghast at the captain of the Kukuru unit being burnt to cinders in front of them by a seven-year-old. Naobito looked too shocked to respond as Shien scowled at the nearest Kukuru member, "Oi, you clean this up!" gesturing to the ash pile.
"Yes! Shi...Shien-sama," he managed to stutter out. Shien walked up the stairs to the Dojo reserved for the Hei to learn barrier techniques. The members of the Hei looked to Naobito for instruction, who simply sighed, "We will deal with this after," he growled, following his child into the dojo.
The dojo seals pulsed once when Naobito slid the doors shut, the paper walls briefly shimmering as the barrier settled into place and swallowed the outside noise. The air turned still, heavy in that particular way barrier spaces always felt, as if the room itself had decided to listen.
Ogi stood near the center mat, arms folded, bokken resting against his shoulder looking sour as usual . Naobito lounged to the side with a cup in hand, being the degenerate he always was.
Shien stepped onto the mat without hesitation and sat properly, back straight, hands resting on his thighs, ready for the lesson.
Shien didn't blink. "Teach me Domain Expansion."
Ogi's eyes narrowed slightly at the directness.
Naobito paused, then chuckled like he'd heard a joke. "No."
Shien tilted his head. "No?"
Naobito's smile stayed light. "A domain is not a child's plaything . It is the highest expression of jujutsu. You don't 'learn' it because you're bored."
Shien's gaze didn't move. "So you can't do it either."
The old man almost dropped his sake bottle .
Ogi's expression stiffened like he'd taken the insult personally.
Naobito's scowled "Watch your mouth, brat."
Shien's voice stayed even. "I am watching it."
Naobito set his cup down, slow and deliberate. "You will not learn Domain Expansion today."
Shien nodded once as if accepting a technical limitation rather than authority. "Then teach me how to counter one . you did promise me "
Ogi's mouth tightened as if he disliked how reasonable that sounded.
Naobito leaned back. "That, I can do."
Ogi stepped forward. "Anti-domain techniques."
Shien's eyes flicked to him. "Simple Domain and Falling Blossom Emotion."
Naobito nodded. "Good. You're not completely illiterate."
Naobito ignored it and raised a finger. "First, understand what you're countering."
He didn't release much cursed energy, but the pressure behind his words was enough.
"A Domain Expansion," Naobito said, "is a barrier technique combined with an innate technique. You construct a boundary that separates inside from outside, then you imprint your cursed technique onto that space. Within that space, the technique becomes unavoidable."
Shien nodded . "The sure-hit."
Ogi nodded once. "Within a complete domain, you don't dodge. You counter, or you die."
Naobito continued. "Domains are decided by refinement. Output and cursed energy reserves matter, but refinement matters more. If your barrier construction is crude, your domain collapses. If the opponent's domain is more refined, your domain gets overwritten."
Shien absorbed it without comment.
Naobito's grin returned faintly. "And that's why it's funny when amateurs get excited about domains. Most of them will never build one."
Shien stared at him. "You're speaking from experience."
Ogi's jaw tightened hard.
Naobito growled and grit his teeth. "You'll get slapped for that one day."
Shien didn't deny it. "Not today."
Naobito waved a hand. "Enough. Ogi, Simple Domain."
Ogi stepped onto the mat and placed one foot down with precision, then traced a circle on the floor with cursed energy. Shien felt the change immediately: the air inside the ring became disciplined, like the space had been told to behave.
"This," Ogi said, "is Simple Domain."
Shien watched carefully, expression blank.
Ogi continued, voice clipped like a lecture. "It is a barrier technique without an innate cursed technique. It creates a neutral zone. In a domain, the sure-hit is enforced by the domain's rules. Simple Domain introduces a competing boundary that disrupts that enforcement within its range."
Naobito added lazily, "In simpler terms, it turns 'guaranteed' into 'not guaranteed' as long as you stand inside it."
Shien's eyes flicked to Naobito. "So you're teaching me to hide in circles."
Naobito smiled. "I'm teaching you to not die like an idiot."
Ogi lifted his bokken. "Demonstration."
He didn't swing the wooden blade. He flicked cursed energy, and the air inside the dojo tightened for a split second as if a technique was about to manifest.
A thin, cutting pressure aimed toward Shien's neck.
Shien didn't flinch.
Ogi directed it instead into the circle.
The moment the cursed energy tried to take shape inside the Simple Domain, it faltered, dispersing like smoke in wind. The attack did not "land," because the sure-hit condition could not lock onto the target within that boundary.
Ogi looked at Shien. "Do you understand."
Shien nodded. "It disrupts the rule."
Naobito's grin sharpened. "Good. Now, Falling Blossom Emotion."
Ogi's expression hardened as if he disliked what came next.
"This one is not a barrier zone," Ogi said. "It is a defensive response."
Naobito spoke, voice amused. "A technique passed down among the Three Great Families. If you have it, you can survive things you shouldn't."
Shien's eyes narrowed slightly. "Survive. Not win."
Naobito smiled as if that pleased him. "Exactly."
Ogi released his cursed energy.
Shien felt it unfold around him like invisible petals, light yet sharp, not a wall but a poised reaction waiting to trigger. The sensation was unmistakable, like a field of blades suspended in air.
Ogi flicked cursed energy again, this time shaped like a strike aimed directly at Shien's chest.
Before it could reach him, the "petals" moved.
The incoming cursed energy was cut down the instant it entered range, shredded into harmless fragments. No resistance, no contest, no brute force. It was automatic interception.
Shien's gaze sharpened. "So it doesn't neutralize the domain's rules."
Ogi nodded. "It counters the sure-hit by destroying the manifested attack before it completes."
Naobito leaned forward slightly. "Domains guarantee the attack will be produced. Falling Blossom doesn't stop production. It stops the result."
Shien watched Ogi for a long moment. "Show the difference."
Ogi scowled. "You order me now?"
Shien's tone stayed polite. "I'm learning."
Naobito chuckled. "Do it, Ogi."
Ogi's eye twitched, but he complied.
He recreated Simple Domain: the ring appeared on the mat again, the neutral zone settling into place.
Then he activated Falling Blossom Emotion around himself, petals unfolding.
Ogi looked at Shien. "Attack."
Shien stood and snapped his right hand.
A precise detonation blossomed mid-air, compact and lethal.
The moment it touched Falling Blossom's range, it was cut apart and dispersed. Clean. Instant.
Shien snapped again, twice, chaining detonations at different angles to test timing.
Each one was intercepted the moment it entered range.
Ogi didn't move. He didn't need to.
"That," Ogi said, voice flat, "is Falling Blossom Emotion."
Shien nodded. "Now Simple Domain."
Ogi stepped into the ring.
Shien snapped again, sending a detonation into the space.
This time there were no petals. Instead the detonation faltered as it tried to manifest inside the neutral zone, weakening as if the space refused to let it become "guaranteed."
It still existed.
But it lost certainty.
It became an attack Shien could miss, waste, or misplace.
Shien's eyes narrowed with understanding. "Simple Domain weakens the rule. Falling Blossom intercepts the manifestation."
Naobito's grin widened. "You're learning faster than I'd like."
Shien glanced at him, expression calm. "Then teach faster."
Naobito snorted. "Brat."
Shien met his gaze evenly. "When do I learn Domain Expansion."
Naobito's smile thinned. "Not for a long time."
Shien waited.
Naobito's eyes sharpened. "Don't look at me like that."
Shien's tone was mild, almost innocent. "I thought the clan head could do everything."
Ogi's mouth twitched like he wanted to laugh but hated himself for it.
Naobito clicked his tongue. "I can do everything that matters."
Shien nodded. "So not that."
Naobito stood up smoothly, cursed energy flaring just enough to make the dojo creak. "dont make me beat you brat."
Shien's expression didn't change, but there was a faint satisfaction in his eyes. "I only wish to learn papa." Shien bowed long and deep.
Naobito stared at him, then laughed again, sharp and dangerous. "Fine. You want to know why you can't learn it yet?"
Shien finally spoke like a child again, but only barely. "Tell me."
Naobito held up a finger. "Because your technique isn't fully expressed."
Another finger. "Because your barrier fundamentals need perfection."
A third. "Because domains require refinement that can't be brute-forced with cursed energy reserves."
Shien nodded, committing everything to memory. Old geysers they might be they still knew things he did not .
Naobito's grin returned. "Until then, you learn the things that keep you alive against people who actually have domains."
Shien's eyes stayed sharp. "So you're teaching me how to kill them before they finish casting."
Naobito's smile widened. "Now you're thinking properly. Speed kills my boy !"
Ogi's gaze remained hard, but he stepped forward again, ready for the next drill, because whether he liked it or not Shien had already understood what mattered.
Domain's were the ultimate move. The checkmate of jujutsu and the ultimate expression of mastery barrier techniques.
Shien wanted certainty of victory more than anything else. The ability to win any fight with one move.
Naobito let the silence stretch after the last demonstration, the kind of silence that carried weight in a dojo like this, then he lifted his cup again as if the lesson had ended.
"You've seen enough," Naobito said, tone casual. "Understanding the theory and executing it are two different worlds. Simple Domain is not a technique you can learn in an afternoon, it's a barrier art that demands stability, output control, and a boundary that needs to be perfect in the heat of battle."
Ogi nodded once, expression stern. "Months," he said bluntly. "If you want it functional. Years if you want it reliable against real domains. One mistake and your boundary collapses, and then you're inside a sure-hit with nothing between you and death."
Naobito added, "A Domain Expansion forces rules onto reality. Simple Domain doesn't override those rules, it introduces a competing boundary that disrupts the sure-hit within its range. If your barrier is sloppy, the opponent's domain will swallow it like nothing."
Shien listened without reacting, eyes tracking the faint residue of cursed energy still lingering in the air where Ogi had traced the circle.
Naobito stood. "That's all. Practice the fundamentals, refine your output, and stop trying to sprint to the peak."
Ogi turned slightly, already dismissing the session in his mind.
Shien moved.
He didn't ask permission, He stepped onto the mat and let his cursed energy sink outward, not as pressure, but as structure, recalling the exact flow he had observed, the exact boundary tension, the subtle rhythm that kept the circle stable. His foot scraped the floor once as he traced a rough ring.
The air inside the circle changed.
It wasn't clean. The boundary flickered at the edges, uneven and jagged like a hastily drawn line, and the stability was nowhere near Ogi's, but it existed. A crude Simple Domain, formed merely through observation and theoretical understanding.
Naobito froze mid-step.
Ogi's head snapped toward Shien so fast his sleeves stirred.
For a moment neither of them spoke, because even they understood what they were looking at.
Shien held the boundary for three breaths, then let it fade like smoke, cursed energy returning inward without a ripple.
He looked up at them calmly.
"So it's possible," Shien said, voice even. "The barrier just needs refinement."
Naobito stared. Ogi's jaw was tight.
Shien tilted his head. "Inside a Simple Domain, can I set additional rules," he asked, tone practical, "or is it always neutral. Can I restrict movement, define entry conditions, set the radius, or add an automatic response like Falling Blossom within the boundary."
Naobito opened his mouth.
No sound came out.
Ogi simply stared at Shien still processing what he had witnessed , The boy had just turned water into wine and now was talking about how to improve the vintage.