"When they get this long, I want to kill someone. So, Principal—do you believe my evidence?"
Kira said calmly.
"I believe you, I believe you... Kira, please put your hand down..."
Perhaps because this particular piece of evidence was extremely compelling and persuasive, Principal Gakuganji nodded with remarkable obedience.
Nanami Kira had always been a perfectly reasonable, ordinary person. He placed his right hand back on his knee.
With his left, he reached into his inner jacket pocket, first producing a clean cloth square, which he spread flat and wrinkle-free on the floor. Then he took out an exquisitely crafted nail clipper.
Click.
Click.
Click.
The crisp sounds echoed off the walls of the small room. That sound always brought Kira a sense of peace—like floating in the center of a vast blue ocean, the gentle murmur of waves washing past his ears.
He clipped his nails and continued the conversation.
"We've caught this early. The curse hasn't spread further yet. Before I… the enemy's next attack, we need to find where the curse was originally cast."
What he actually wanted to say was: Before I clock out.
"Kira, that's incredibly difficult. Kyoto is enormous—finding where the curse was cast is like searching for a needle in the ocean. How about I deploy half the school's sorcerers to assist you?"
Kira gave Gakuganji a meaningful look and shook his head. "That won't be necessary."
He brushed his hands off, tapping the clipped nails onto the cloth spread on the floor, then carefully funneled them into a small glass bottle. Only after he'd finished this ritual with meticulous care did he exhale with relief, wipe nonexistent sweat from his brow, and stand up.
"I have a rough idea where the curse was cast."
"Oh?"
Gakuganji's eyebrows jumped, but he masked his surprise well and asked warmly, "Where?"
Kira pulled a rolled-up map from inside his jacket, spread it flat on the low table, and took a marker pen from his breast pocket. He began marking the map.
"Here's what we know so far: an unknown curse, cast two weeks ago."
"Mm, and then?"
"It spreads through negative emotions and can pass from person to person."
"Then it's simple. We can treat it like a virus—wherever the infection is worst is where the outbreak started. Where are people the most desperate, the most emotionally drained?"
"All you've done is go from searching for a needle in the ocean to searching for a needle in a lake. Are you going to send sorcerers door-to-door with surveys? Walk up to everyone and ask, 'Excuse me, are you happy? Is your marriage going well? Is that kid actually yours?'"
"There's no way to investigate something like that."
Kira nodded in agreement. "With just that, correct—it's impossible."
"But there's another property: the Cursed Energy fluctuation is extremely faint, undetectable. Even sorcerers like you and me were cursed without noticing a thing."
"Kira, I apologize for doubting you earlier. Just stop with the suspense."
"...The symptoms differ between victims. I believe it's correlated with their jujutsu grade." Kira said, satisfied.
Gakuganji straightened up, assuming the posture of an attentive listener.
"Your student Mai Zenin has been fighting with Momo Nishimiya. Their grade is Grade 3. Kasumi Miwa has been in a terrible mood; her grade is Semi-Grade 2. You and I are both Grade 1-level, and we've been occasionally losing control of our emotions..."
"As for ordinary civilians—I've seen someone dismember another person out of sheer hatred. I've seen people sink into depression and lose themselves in nightclubs. I've seen people leave Bad Luck Money at the doors of close friends and family."
"And then there's the steadily climbing suicide rate. Clearly, the curse's impact on ordinary people is far more severe."
"From this, we can deduce another property: the degree of cursed contamination is inversely related to the victim's Cursed Energy. If the curse is a virus, then Cursed Energy is the immune system."
"Go on."
"That gives us two properties of this curse: transmissibility and resistance. Using the virus analogy, there should be a third."
Kira set down the marker pen, paused, and looked Gakuganji in the eyes.
"Locality."
"The closer you are to the curse's source, the stronger the negative emotions, and the more susceptible you become. This is easy to demonstrate: you and I both have considerable Cursed Energy—a strong immune system—yet we've both been affected."
"Meanwhile, civilians in Ukyō Ward seem mostly fine, and the suicide rate there isn't alarmingly high. There's only one explanation: relative to Ukyō Ward, we're closer to the source."
"So we can build a propagation model for this curse."
Kira dropped a spot of marker ink into the tea. The black ink slowly darkened the center, then spread outward. At the core it was pitch black; the further out, the lighter it became, until near the rim it was just a faint grey blending into the pale green tea.
"The darker the ink, the more people are cursed. It radiates outward from the source in all directions, growing weaker with distance. A circular infection zone."
He tapped a point where grey met pale green. "This is Ukyō Ward's position."
"And then?"
Gakuganji's expression grew increasingly grave. His fingers tapped the edge of the table unconsciously, brows locked tight.
"We still can't pinpoint the exact location."
"Our Cursed Energy levels are comparable, and our degree of infection is the same," Kira replied.
The only difference is that your loss of control means flipping tables, and mine means killing people.
In Kira's mind, people weren't much more important than tables. They held the same status.
Therefore their degree of infection was naturally the same.
"A curse isn't entirely analogous to a virus. Viruses carry uncertainty—they're influenced by all sorts of factors. Curses are different. They're singular and rigid, operating strictly according to fixed rules."
This was one of the reasons Kira had chosen to become a jujutsu sorcerer. He liked things that followed rules.
Gakuganji's expression grew more solemn. He could sense the crux approaching.
"Our total Cursed Energy is comparable, our degree of infection is comparable—therefore, by the curse's second property, our distance from the source must also be comparable. Virtually identical, in fact."
Kira marked a point in a brownish-black area of the map. "This is my apartment."
He marked another point on the opposite side, silently counting the distance. "This is your location—the school."
"You learned this in middle school, right?"
As he spoke, he drew a line connecting the two points through the tea-stained map, found the midpoint, and drew a perpendicular line through it.
"The source of the curse lies somewhere on this perpendicular bisector."
"I suppose total Cursed Energy can be estimated, but the degree of infection? That's psychological—extremely hard to quantify..."
"I studied criminal psychology for several years, and I've studied law. Based on my observation of your behavior just now, I'm confident that your anxiety level is comparable to mine."
Kira answered without looking up.
Why would a jujutsu sorcerer study criminal psychology and law... Gakuganji pinched the bridge of his nose.
"Even if there's some margin of error, it's within acceptable tolerance."
Kira glanced at his watch, then put the pen back to the map, circling and marking. "Mapping the model onto the real geography... here's the school... here's my position... connect them, draw the perpendicular."
He set down the pen and pointed at the black line on the map.
"The source is somewhere on this line... or near it."
He erased the majority of the line—those segments were closer to Ukyō Ward, and by his reasoning, Ukyō Ward should be farther from the source than either of them.
"Eliminate the uninhabited areas, and we'll find the exact location soon enough."
Kira reached his conclusion.
"...I'll have people on it immediately." Gakuganji nodded firmly, admiration plain on his face. "Kira, thank goodness for you! They don't call you the most unique sorcerer in history for nothing!"
Tch. Drama queen.
Kira thought it, but wore a humble smile. "You're too kind."
Just as he'd thought from the beginning—this had been a completely pointless conversation. He just wanted to go home.
Summer weather was nothing if not fickle. One moment the sun was shining; the next, clouds piled upon clouds, pressing thick and dark against the dim horizon.
A silver bolt of lightning sliced through the clouds, and the sky's reservoir came crashing down—rain hammering the newly headed wheat.
It was raining. Good thing he'd brought an umbrella.
Beneath his black umbrella, Kira tilted the handle slightly, nudging the rim out of his line of sight. Before him stood row upon row of sorcerers clad in black.
They stood in the downpour, hoods pulled up, the buckles on their black boots glinting cold.
"Let's go."
Kira turned. His boot landed in a puddle, sending out tiny ripples—then the ripples never stopped. Behind him, black boots fell in lockstep, splashing water into the air.
Watching the sun slowly swallowed by storm clouds, and Kyoto bathed in rain, Kira thought to himself:
Let's go. Before I clock out.