The first-year students' first mission came just a few days after they'd met for the first time.
A cursed womb had been confirmed at the site. Ijichi had escorted them there with that quiet efficiency he brought to everything that didn't require a personal opinion, and now they stood in front of the building as the morning light fell over a place that had clearly gone a long time without seeing anything close to normal.
Rei already knew before anyone told him.
Gojo was out of the city — a business trip, they said — and while it could have looked like bad timing, Rei knew enough about how the higher-ups operated to know it wasn't a coincidence. Didn't matter whether it was the jujutsu world or the real one: people in power always found a way to get rid of whoever they considered an inconvenience. Sending first-year students on a mission of this scale, unsupervised, with Itadori in the group — that wasn't carelessness. That was a calculation.
Rei said nothing. There was nothing to say that would change anything.
That was when the voice came.
"Is Tadashi...? Is my son okay?"
A woman had crossed the security perimeter before anyone could stop her. Her voice had that particular texture of fear that's been held in for hours — quiet, almost reasonable, like she still believed that if she asked calmly enough she'd get an answer she could live with.
Rei glanced at her for a second. Then he looked at Itadori.
That was enough to see what was happening. Itadori hadn't said anything yet, but something in his posture had shifted — that specific tension of someone who's made a decision before they've finished processing it.
"Fushiguro. Kugisaki. Kagami."
He called all three of them. Then he turned toward the building with that straightforward, no-frills determination he brought to everything that actually mattered.
"We're saving them."
It wasn't a question or a suggestion. It was simply what was going to happen, because Itadori Yuji didn't know how to frame things any other way.
Rei exhaled through his nose. He went in with the others.
The domain had taken over everything.
It wasn't an active expansion — it was something older and more passive, the territory of a cursed womb that had been given enough time to seep into every wall, every hallway, every staircase of the building and warp it from the inside out. The corridors stretched further than the architecture allowed. The staircases led to floors that didn't exist from the outside. The air had that specific density of places where cursed energy has been accumulating so long it's forgotten it's energy — it's just the atmosphere now, and the atmosphere is hostile.
They moved together until they couldn't anymore.
They found bodies. The first one stopped all of them for a moment — not out of surprise exactly, because none of the four were completely unfamiliar with what the jujutsu world involved, but with that particular weight of confirming something you were hoping you wouldn't have to confirm.
Among the bodies was the woman's son.
Yuji stared at him longer than the others did. Rei noticed and said nothing.
The argument started slow and escalated fast, the way arguments escalate between people who fundamentally want the same thing but can't agree on how to get there. Yuji wanted to take the body — without it, the woman would have nothing concrete to hold onto, nothing that would let her even begin to process what she'd lost. Megumi wanted to leave it. There were other possible survivors, and the time it took to carry a dead person was time someone alive might not have.
They were both right. That was the problem.
"If you save someone today," Megumi said, with that coldness he used when he didn't want it to show how much something cost him to say, "and that person kills someone else tomorrow — what do you do?"
"Then why did you save me?"
Yuji's question landed in the silence like a stone dropped into still water.
Neither of them spoke for a moment. Rei watched from the side without stepping in. It wasn't his argument — and besides, he didn't have a better answer than either of them.
It was Nobara who tried to stop them.
The floor swallowed her before she could finish the sentence.
The silence that followed lasted exactly as long as it took the three of them to process what they'd just seen. Then Megumi was already moving, reaching for his shikigami on instinct — and finding it. Embedded in a wall. Still.
"Itadori! Kagami!" There was an urgency in Megumi's voice that Rei had never heard from him before. "Run! We'll find Kugisaki after."
Neither of them moved.
Not by choice — it was just that bodies sometimes have their own opinion about what's possible. The pressure filling the hallway was a completely different density from anything Rei had faced before. It wasn't exactly pain. It was more like being at the bottom of something very deep, with the full weight of the water above you.
A Special Grade.
Rei recognized it the same instant the silhouette emerged from the far end of the hallway. It had a humanoid shape — like his father when he transformed — but on a scale his father never reached. The curse didn't walk toward them. It was simply far away, and then it was close, and the space between those two states meant nothing to it.
Rei moved.
He appeared between the curse and the other two before either of them could react — one hand on Itadori's shoulder, one on Megumi's, and all three of them were already three meters back when the space they'd been standing in filled with concentrated cursed energy that left the floor marked with something that wasn't exactly a burn but wasn't anything else either.
"Don't stand still," Rei said, with a calm that took more effort than it looked. "You'll die."
It was his first time facing a Special Grade. He knew that. The weight of that curse in the air was qualitatively different from anything before it — not harder in the sense of faster or stronger, but different in a dimension Rei was still learning to measure.
That was when the mouth appeared on Itadori's face.
"I refuse to help you."
The voice was Sukuna's — or more precisely, it was Sukuna using the mouth he'd carved into Itadori's face as a communication terminal, with the indifference of someone having a mildly dull conversation while the world falls apart around them.
"It's so frustrating not being the one in control of this body." A pause. The tone shifted slightly — not warmer, but more interested, and in Sukuna those two things were almost the same. "Though if you want me to take over, I wouldn't mind..."
Itadori clenched his teeth.
"But if that happens," Sukuna continued, with the ease of someone who's already calculated the ending, "I'll kill your friends before I go after that spirit. Then I'll go after the woman."
The curse concentrated energy into what it used as a mouth and fired toward Rei. The impact never landed — Rei was already gone. He reappeared directly in front of the curse, fist already moving, and the crash when it connected echoed through the entire hallway as the curse was sent through the wall and into the darkness on the other side.
"Focus," Rei said, pulling his teammates' attention back.
He turned to Megumi and Itadori. The cursed energy he was releasing without effort filled the corridor — dense, that dark violet that set it apart from the standard black of most sorcerers, pulsing with an intensity neither of them had seen from him until now.
"Fushiguro." He looked at him directly. "Go find Kugisaki. Once you're outside with her, give us a signal. Anything. We just need to know you're both alive."
He didn't try to get Itadori to leave too. He knew that would be a lost cause.
Megumi opened his mouth.
"Fushiguro." Itadori stepped forward, with that calm that came over him precisely when things were serious enough to need something more than just instinct. "Trust us."
Megumi looked at them both for a second. He wasn't convinced — that was obvious — but he didn't have a better argument, and Nobara was alone somewhere in that building.
He left without another word. His footsteps faded down the hallway.
The curse pulled itself back together.
The Special Grade didn't fight like the curses Rei had faced until now. There was nothing resembling a pattern — but it wasn't mindless either. The first wave of cursed energy burst outward from its body in every direction. Itadori, who was closest, took the full impact and was thrown into the wall hard enough to crack the cement.
The curse was already on top of him before he hit the ground.
Rei appeared between them — Nisoku lets him skip the movement entirely, existing directly at the endpoint — and the blow meant for Itadori met his reinforced forearm instead. The impact traveled up his arm to his shoulder with a force that would have shattered the bone of anyone who wasn't saturating every fiber of their body with cursed energy.
Rei held. Then pushed back with the same forearm that had absorbed the hit.
The curse stepped back half a meter. Not much, but enough.
"Itadori." He kept his eyes on the curse. "Feel your cursed energy. Guide it — cover every part of your body with it. Use it to reinforce yourself."
Itadori got to his feet. He had blood at the corner of his mouth and the look of someone who had just drastically revised their read on the situation.
"I'll try," he said, and he meant it.
The curse attacked again — faster this time, as if it had recalibrated after taking that hit. Rei shifted right before the attack arrived, reappeared to its left, and landed two consecutive strikes on the same point with Kaimetsu active.
The first hit did the damage it should have done.
The second carried the first hit's damage on top of its own — triple the original impact.
The third, thrown a fraction of a second later, stacked everything before it: nine times the damage of a normal strike, concentrated on the exact same point.
That was the essence of Kaimetsu — a paradox of cause and effect where each consecutive hit didn't just add but multiplied over what had accumulated, like compound interest applied to destruction. The damage existed before the blow landed, during the impact, and after it ended, all collapsing into the same instant from three separate moments in time.
The curse roared. It was the first time it had done anything that looked like an involuntary reaction.
But it didn't fall. The curse pulled itself upright again.