Three months had passed since they declared themselves "The Strongest."
The morning sun spilled through the windows of the Jujutsu High dorms, bathing the room in a warm, amber glow. Geto sat on the balcony in his high-collared uniform, his dark hair fluttering in the light breeze. In one hand, he held a steaming cup of coffee; on his lap rested a heavy, hardcover volume titled The Three Great Clans.
"Suguru, what the hell is so interesting about that book?" Gojo called out from his bed. He didn't look up, his thumbs flying over the buttons of an old-school handheld console. "It's just a bunch of old fossils stroking their own egos."
"Actually, it's not half bad," Geto replied, taking a slow sip of his coffee. "The founder of the Zenin clan is quite a character. They call him the 'Father of the Modern Jujutsu World,' though it seems his descendants have strayed pretty far down the wrong path."
"Whatever. Who cares? The Zenin clan is gross," Gojo grumbled. A sharp Game Over sound echoed from his console. "Ugh! Piece of crap!"
"True enough," Geto said, closing the book with a soft thud. He turned his gaze back to his friend. "That aside, how's your progress with Reverse Cursed Energy?"
"Oh, that?" Gojo tossed the console onto his pillow and sat up, a cocky grin spreading across his face. "It's going great. Check this out."
Gojo reached into a nearby drawer and pulled out a sharp utility blade. With a casual flick, he sliced a deep gash along his forearm. Before the blood could even bead on the surface of the skin, the wound hissed, sealing shut in a cloud of white steam.
"Hmm. It's fast," Geto admitted, impressed. "But it's not automated like the Infinity you perfected last month."
"Nah, that's probably not happening. I'm already using RCE constantly just to refresh my brain so I can keep Infinity active 24/7," Gojo replied, flexing his arm.
Geto finished his coffee and stood up, walking toward the balcony railing. "So, how do you actually do it? The Reverse Curse Energy, I mean."
"Well, you know..." Gojo stood up and began making wild, animated gestures. "It's like... Boom! Bash! You just flip it!"
"That's not how you ex—"
"OI! YOU TWO!"
Shoko's voice drifted up from the ground floor, sharp and annoyed. "Yaga-sensei is going to murder you! He's been waiting in the classroom for ten minutes!"
""Ah, hell."" the two boys cursed in unison.
Without a second thought, Geto leaped directly from the balcony. He landed gracefully, scooped Shoko up into a princess carry, and took off.
"Huh? Hey!" Shoko let out a confused sound, startled by the sudden lift.
"Satoru! Let's race!" Geto shouted over his shoulder, already reinforcing his legs with cursed energy to hit top speed. "Winner buys lunch!"
Gojo stood on the balcony, fuming. "You cheating bastard! You took a head start!" He smiled, his Six Eyes sparking with excitement. "Fine. Let's try the new move."
He clasped his hands together, focusing on the coordinates of the classroom. "Cursed Technique Lapse: Blue."
Gojo folded the space between his current location and the classroom, intending to teleport instantly. But a millisecond into the transition, his Six Eyes picked up an anomaly in his path.
A Grade 2 curse—specifically one with a physical form Suguru must have placed there—was hovering right in his trajectory. It was a "Stubbed Toe" curse, a minor spirit that specialized in bypassing automated defenses by being a nuisance rather than a "threat."
"DAMN IT, SUGURU!"
Gojo hadn't perfected the long-range stabilization of the technique yet. He couldn't stop. He collided with the obstacle, obliterated it, and went crashing through the classroom wall just as Yaga was sitting down on his chair.
BOOM
Gojo felt a wave of phantom pain ripple through his body—the kind of sharp, blinding agony you feel when you hit your foot against a door frame. Since it wasn't a "hostile" attack, his Infinity hadn't filtered it out.
He gritted his teeth and stood up, dusting off his uniform. Geto was already there, still holding Shoko, a smug, slightly sullen look on his face.
" NOT AGAIN! at least use something different, it's getting pretty boring now"
Geto just smiled and said in indifferent tone "It's not boring if it works"
Before Gojo could reply, Yaga-sensei moved with a speed that defied his bulk.
Thwack! Thwack!
He delivered a double-fisted hammer blow to the tops of both boys' heads.
"No more games," Yaga growled, his voice vibrating with anger. "Get to your desks. Now."
Shoko, still tucked under Geto's arm, tapped his shoulder. "Also... can you let me go now?"
"Oh. Right. Sure," Geto said. He opened his arms, and Shoko dropped straight onto the floor with a dull thump.
"Ouch! You bastard!" Shoko stood up, brushing off her skirt, and swung a punch at Geto. Before the punch could land a small, protective curse manifested in front of him, taking the blow for its master.
"Hmph. Infuriating." So, she just punched the air this time.
The trio finally took their seats. Yaga turned to the blackboard and began writing.
Gojo and Geto following the order of their sensei didn't make any scene and started scrubbing in same notebook.
Gojo: What the hell was that curse you put in my way? That was so fricking painful. I am not letting you go away with that.
Geto: Hehe. Grade 3: "The Coffee Table's Corner." It doesn't do damage; it just simulates the sensation of pain from maximum-velocity stubbed toe. It's a conceptual hit, so your Infinity ignores it.
Gojo: You're a literal demon. Anyway, when did you figure out, I could teleport? That was supposed to be my grand reveal.
Geto: I didn't. I just figured if you were racing me, you'd try something flashy and reckless. It was a 50/50 guess.
Gojo: Tch. Whatever. You and me outside, after the class.
Shoko the third wheel intervened in their conversation. Shoko: LOOK AT THE BOARD.
There, Yaga has written the today's topic in thick bold letters.
THE BLACK BUTTERFLY (黒蝶, Kurochō)
[ Black Butterfly (黒蝶, Kurochō) is an extension of the ten shadows that functions as a Barrier Technique accessible to any sorcerer through specific ritual scripts created by First user of Ten shadows and founder of Zenin clan Naruoko Zenin.
Description: By imbuing a specialized script with cursed energy, the sorcerer programs a barrier that manifests as a liquid-shadow butterfly, sinking into the darkness to navigate a subspace dimension.
This messenger bypasses all physical obstacles, seeking the unique cursed energy signature of its recipient to emerge silently from their personal shadow.
A technique born from the principles of 'ten shadows ' and 'barrier techniques' like curtain. it converts written intent into a secure, untraceable transmission through the interconnected shadows of the world. ]
"The Black Butterfly was a revolutionary technique of the Heian era," Yaga said, looking at his students. "Any questions?"
Gojo's hand shot up at light speed. "Sensei, can we go to lunch now?"
"Denied," Yaga replied deadpan. He looked at Geto.
"Why haven't we heard of this until now?" Geto asked. "A secure, untraceable messenger seems incredibly useful."
Yaga sighed. "It was useful in its time. But with modern technology, a text message is faster. Plus, it requires deep knowledge of barrier rituals. Most modern sorcerer find it too tedious to learn since they are already having their hand full of learning offensive techniques."
"It seems way ahead of its time," Shoko remarked.
"It was," Yaga agreed, a small, genuine smile touching his lips. "It's a masterpiece of 'Jujutsu'—converting written intent into a shadow transmission. Let me show you. And remember: you have to smile during the incantation, or the ritual won't stabilize."
Yaga took out a piece of paper marked with a butterfly script. He wrote the word 'Hi' on it, then clasped his hands in a prayer position. With a wide smile, he recited the incantation:
" Unholy the holy, most humbly I implore you.
Please send the message to the one I desire: Suguru Geto."
On the final word, the paper dissolved into a shimmering black liquid. It took the shape of a butterfly and dived into Yaga's shadow. Instantly, it fluttered out of Geto's shadow and rematerialized into the physical paper on his desk.
Gojo and Shoko huddled around Geto to inspect it. The word 'Hi' was clearly visible. After a minute, the paper withered away into gray dust.
"Can it be used to attack?" Gojo asked, his mind already racing with tactical possibilities.
Yaga's expression turned deadly serious. "No. This technique is strictly for communication. Any attempt to tamper with the script or use it for harm is met with violent backfire. The ritual is fragile."
Yaga turned to leave the classroom, pausing at the doorway. His stern voice echoed back to them: "Do not—under any circumstances—tamper with the Black Butterfly."
As soon as the door clicked shut, Gojo, Geto, and Shoko looked at one another. A slow, mischievous grin spread across all three of their faces.
"Hehehehe..."
.
.
.
.
Ten seconds later, the room went still.
The classroom was a disaster. The floor was scorched, the desks were splinters, and the two "Strongest" sorcerers and best healer were piled in a heap in the corner. Gojo's hair was standing even straighter than usual from the electricity, Geto was covered in soot, and Shoko was flat on her back, staring at the ceiling with a dead-eyed expression.
The door creaked open. Yaga stood there, his sunglasses reflecting the utter calm .
"I told you," Yaga said, his voice terrifyingly calm, "not to tamper with the Black Butterfly."
Gojo and Geto both raised a shaking hand from the bottom of the dogpile. "...Worth it."
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