The flat, heavy blade of the Demon-Slayer Sword met skin.
Or, it should have.
Asta felt no impact. There was no clang of metal, no resistance of flesh. Instead, the sword's tip fizzled as it touched Saitama's cheap yellow jumpsuit. A flicker of crimson-black energy sputtered and died.
To everyone else, it looked like nothing happened.
But Asta saw it. Through his connection to Anti-Magic, for a fraction of a second, the world fell away.
He didn't see a person. He saw a shimmering, golden cage, forged from an impossible light. It was vast, metaphysical, containing a universe of roaring, silent power.
And his sword had just scraped against one of the bars.
He saw a hairline fracture run along its surface. A tiny crack in a cage holding back infinity. A single, agonizingly bright thread of energy pulsed from within.
Then it was gone. The man was just a man again. A bored, bald man looking down at his chest where the sword was still resting.
"Your sword is broken or something?" Saitama asked, poking the dull edge. "It's making a weird buzzing sound."
The sensation was so overwhelming Asta fell back, landing hard. He stared at his hands, then at the man. His heart hammered against his ribs. It was a pressure a thousand times greater than the devil he'd just faced.
He saw an attack coming, but not for the man. For him.
"You dare raise a weapon against Sensei?!"
Genos moved. A blur of chrome and black plating. His left arm unfolded, plates shifting to reveal the glowing maw of an incinerator cannon, aimed directly at Asta's face. The air warped with heat.
"Threat identified. Neutralizing."
"Stand down, Genos," Saitama said, not even turning around.
Genos froze instantly, cannon still primed, every fiber of his synthetic being screaming to defend his master. But an order was an order.
"But Sensei, he attacked you—"
"He didn't even scratch the suit. It's fine."
A gravelly voice cut through the tension. "He's right, Tin Can. Stand down."
Yami Sukehiro limped forward, katana resting on his shoulder. Blood dripped from his chin, but his eyes were sharp, his Ki sense fully active. He wasn't looking at Asta. He was looking at Saitama.
And what he felt made the hairs on his arm stand up.
Nothing. An absolute and total void. No mana, of course. But no Ki either. Where a person's life force should be, there was just… an empty space. A human-shaped hole in the world. It was profoundly unnatural. Terrifying.
Yami glanced at Asta. "Kid. What did you see?"
Asta swallowed, scrambling to his feet. "I-It wasn't magic. It wasn't anything I've ever seen. A seal… or a… limit. His power, it's—"
"Contained," Yami finished, his gaze locked on Saitama. The puzzle pieces were clicking into place. An impossible punch from an impossible man.
Saitama just looked back and forth between them, completely lost. "Are you guys gonna fight? If not, can someone point me to the nearest supermarket? I was supposed to get stuff for hot pot."
Yami let out a rough laugh, a cloud of smoke escaping his lips. This was perfect. The sheer absurdity of it was exactly his style. A weapon that didn't know it was a weapon. An ace that didn't even know the game.
He needed this man.
"You. Baldy."
Saitama pointed to himself. "Me?"
"Yeah, you," Yami said, sheathing his sword. "You got a place to stay?"
"Don't think so."
"Anywhere to be?"
"Was chasing a mosquito. Kinda lost track of it."
Yami grinned. It was a feral, calculating thing. "Good enough for me. From this moment on, you're a member of my squad."
The battlefield, which had just started to stir with medics and recovery teams, went dead silent again.
Finral, who had been struggling to open a portal with his depleted mana, tripped over his own feet. "Captain, you can't just—!"
Noelle stared, aghast. "He has no magic! He can't even be a Magic Knight!"
"Don't care," Yami grunted, jabbing a thumb at Saitama. "This guy's got good vibes. Weird, empty, punch-a-hole-in-reality vibes." He turned back to Saitama. "I'm making you a Black Bull."
Saitama blinked. "A what? Is that a brand of beef?"
"Best damn Magic Knight squad in the kingdom," Yami declared. "Means you work for me now. We got a place to crash and the food's not always poison."
Saitama considered this for a moment. A long, thoughtful moment.
"...Is there food today?"
"Probably."
"Okay, I'm in."
The collective whiplash almost knocked the recovering knights over. Genos tilted his head, processing.
"Sensei," he said formally, "Registering with a local armed faction may provide us with valuable intel and resources. I approve of this tactical decision."
Saitama just shrugged. "He said there's food."
As if summoned by the sheer chaos of the moment, something drifted into view.
It was a book. An old, thick grimoire bound in cracking, unmarked leather. It had no insignia. No five-leaf clover, not even a three-leaf. Its pages were yellowed but completely blank.
It floated silently in the air and came to a stop about three feet away from Saitama's shoulder.
Saitama stared at it. "Did one of you guys drop this?"
He waved his hand at it. The book wobbled, then drifted right back to its spot.
Asta's jaw was on the floor. "A grimoire… it's choosing you."
"Why?" Saitama asked, looking genuinely annoyed. "I don't need a book."
"It doesn't work that way!" Asta shouted, his earnestness overriding his shock. "Grimoires choose mages whose mana resonates with them! It's a sign of being chosen by magic itself!"
"But he has no mana," Noelle added, her voice a whisper of pure confusion. "How is that possible?"
The blank book bobbed in the air, a silent, impossible statement.
Saitama poked it. It felt like old leather. He sighed, the deepest sigh of a man who just wanted to go home and was now being saddled with cosmic responsibility and haunted literature.
"Fine. Can it carry groceries?"
Miles away, in his office atop the Magic Knight headquarters, Julius Novachrono felt a tremor in time itself.
His own grimoire, a massive, coverless tome whose pages were infinite, was fluttering wildly. Time magic, the very force he commanded, had hiccupped. A moment had been erased. Not fast-forwarded or reversed. Simply… deleted.
He walked to his window, looking out over the capital city now blessed by a sun it shouldn't have been able to see. The threat was gone. An impossibility had occurred.
A small, delighted smile touched his lips. His eyes, for a brief second, glowed with the raw power of his magic, ticking forward through endless possible futures.
But one path, the one that had just opened up, was completely dark. A total blind spot.
He had never been so excited.
"Incredible," Julius breathed, his voice filled with a terrifying, childlike wonder.
"A future I couldn't see has just begun."