The night after Kuraiden's defeat was strangely calm. No more cursed clouds, no spiritual pressure twisting the air, no death howling in the distance.
Just the hush of recovery.
But Riku wasn't sleeping.
He sat cross-legged at the shrine, alone under the pink-and-gold hue of approaching dawn. His shirt lay folded beside him, torso crisscrossed with scars from cursed feedback. A single candle burned before him, flickering in the windless air.
The pages of a hand-bound scroll fluttered open in front of him. Not an exorcist manual, not a curse-user journal—but something far older.
A binding vow ritual.
> "To surpass oneself, something must be given. What are you willing to lose, to gain something greater?"
He stared at the ink, remembering how Gojo once joked that Binding Vows were either for maniacs or madmen. Sukuna, in his past life, had used them to enforce the kind of monstrous power balance only a demon king could wield.
But Riku wasn't Sukuna.
Not exactly.
He breathed in deeply. His cursed energy flared, but not wildly—it flowed in a smooth spiral around his body, forming runes in the air, circling like fireflies.
His goal: limit his use of Cleave to enhance its lethality.
His vow: If he misjudges his opponent's cursed energy level during Cleave, the attack will rebound on him at double intensity.
The price? Immediate, brutal backlash for sloppy control.
He wasn't looking for safety. He was chasing perfection.
He bit his thumb, letting blood spill onto the scroll.
> "I, Riku, forge this binding vow: Cleave shall judge only the unworthy. If my strike fails in judgment, let it judge me instead."
The blood sizzled. The runes snapped into place. The cursed energy tightened like chains around his arms—painful, raw, but precise.
Then it sank into him.
The vow was complete.
A sharp gasp left his mouth. His vision went white for a moment.
When it cleared—he felt different.
His body didn't feel heavier. But his mind was sharper. The feedback from his cursed techniques clearer. The connection to Cleave was like hearing the technique breathe.
> Good, he thought. This is a step forward.
> Even Mahoraga will have to acknowledge this one day.
But as the first rays of dawn crept over the horizon, he felt another energy—unfamiliar, stalking nearby.
"Your ritual was pretty," said a voice behind him. "But dangerous."
He turned slowly.
A man in a long white coat stood on the shrine's top step, leaning on a twisted staff carved from human bones. His hair was black, slicked back, and his eyes glowed faintly red. He had the scent of decay and vanity.
A rogue sorcerer. But not the modern type. This one was old—from before exorcism was organized.
"Who are you?" Riku asked, standing.
"The dead don't need names," the sorcerer smiled. "But call me Seido. I'm here for your eyes. They don't belong in this world."
Riku's golden irises narrowed. "You know I'm not normal."
"Please," Seido scoffed, "that much cursed energy in a boy's body? You might as well wear a sign."
Riku raised a hand, cursed energy flaring.
Seido responded with a flick of his staff, launching hundreds of bone shards like needles.
Riku moved instantly—dodging with grace, arms glowing with cursed sigils.
> "You want my eyes?" he said coolly. "Then let's see if you deserve to look at them."
He snapped his fingers.
> "Cleave."
A red slash whipped through the air—fast, calculated.
But Seido vanished, reappearing behind him.
Riku barely blocked in time, shadows flickering around him.
"Fast," Seido said, "but reckless."
A bone lance grazed Riku's shoulder—he grunted as blood splattered. The vow activated.
A second slash exploded into his arm—his own Cleave rebounding.
He gritted his teeth. So that's the cost.
Still, he smiled.
"Pain's part of the lesson," Riku muttered.
Then, his hands moved in rapid signs.
> "Ten Shadows Technique: Rabbit Escape."
Hundreds of shadow rabbits burst from beneath him, blinding Seido's vision.
Riku ducked low and launched upward with an uppercut, followed by—
> "Cleave. No Mercy."
The cut struck Seido's ribs with bone-splintering force. The sorcerer staggered, coughing blood.
Seido's staff spun, readying another strike—but Riku had already vanished.
From above:
> "Nue."
Lightning surged down, crashing into the rogue sorcerer and sending him flying into a shrine wall. Dust exploded. Statues cracked.
When it settled, Seido lay there, groaning.
"You're not human," he spat.
"No," Riku agreed. "But I'm real enough to break you."
He raised his hand to finish it, but Momo and Aira arrived just then, weapons drawn.
"Are we interrupting a cursed bromance?" Momo asked dryly.
Aira sighed. "Riku, seriously?"
Riku lowered his arm.
"Keep him alive," he said. "I want to know who sent him."
The sun crested the sky. The vow held tight inside him, thrumming like a heartbeat.
And in that first light, Riku smiled.
Another step forward. Another piece in place.