Chapter 0 : The Unseen Crack
The wind howled above Harken Cliff, where storm clouds loomed like beasts waiting to descend. Lightning tore the sky in jagged flashes, illuminating the figure standing at the edge—his tattered black cloak fluttering violently in the storm.
Asta, the boy born without magic, the wielder of anti-magic, and now a hero of the Clover Kingdom… stood alone.
In his right hand, his massive sword pulsed faintly with dark energy—Demon Slayer. In his heart, something stirred. A pressure. A presence.
"This feeling again…" Asta muttered under his breath, sweat mingling with rain on his brow. "It's like… the world itself is trembling."
Behind him, shattered stones and scorched earth marked the remains of a battle. A strange creature—neither beast nor devil—lay dissolved into nothingness. It had spoken in a tongue no one alive should have known, and before it vanished, it whispered a warning:
"The first seal is broken."
Asta had no idea what it meant. But he felt it—something ancient had shifted. Something that shouldn't exist in this world… was awakening.
Back at the Black Bulls' Hideout
The hideout, usually chaotic and loud, was unusually quiet. Even Luck wasn't running around breaking things, and Magna had paused mid-workout. Everyone was watching Asta, who sat cross-legged in the common room, lost in thought.
Yami leaned against the wall, a cigarette burning low between his fingers.
"You look like you saw a ghost," the captain muttered.
"I saw something worse," Asta replied. "Or maybe... something older."
He recounted what happened at Harken Cliff—the creature, the strange pressure, and the words about a seal. As he spoke, the air seemed to thicken. Grey looked uneasy. Noelle's hands tightened into fists.
Vanessa took a long sip of wine. "That kind of magic… it doesn't sound like anything we've faced before. Not devils. Not curses. Something else."
"That's because it is something else," a new voice interrupted.
They turned to see Nacht, the vice captain, emerging from the shadows with his devil companion hovering silently behind him.
"I've been tracking rumors," Nacht said. "Seven ancient crests, scattered across the lands. They're called the World Seals. Each one binds a different layer of reality—magic, time, even memory itself. If they break…"
He didn't finish.
"Then we stop them from breaking," Asta said firmly.
But Nacht's gaze was unreadable. "It's not that simple. These seals… aren't guarded by monsters. They're guarded by choices. And every time you act… the world itself may shift."
A heavy silence fell.
Then Asta stood. "I don't care how old or powerful these seals are. If they threaten this world—our world —I'll destroy whatever stands in the way."
Noelle looked at him, her heart pounding.
"You always rush forward like that," she whispered.
"That's because someone has to," he smiled.
But far from the Black Bulls, in a forgotten cave where even mana refused to dwell, a second crest—cracked and glowing—began to hum with life.
And something… someone… stirred from slumber.