Transmigrated As Satoru's Father (A Jujutsu Kaisen Fanfiction)

Chapter 13

Seijuro stood in the newly reconstructed training ground, the faint smell of freshly polished wood and repaired stone lingering in the air. His body was still wrapped in bandages, the dull ache of his healing wounds a constant reminder of his battle with Toji. He took a deep breath, his crimson eyes narrowing as he focused.

"Okay, how do I do it again?" he muttered, staring at his hands.

During his fight with Toji, the destructive energy had surged from him naturally, as though it had a mind of its own. He hadn't consciously summoned it—his instincts had taken over, driven by desperation and survival. Now, he wanted to understand, to control it. But how?

Seijuro closed his eyes, taking another deep breath. He concentrated, trying to recall the moment when his life had been on the line. He tried to remember the emotions he'd felt: fear, anger, the primal urge to destroy, to survive.

The air around him crackled faintly.

—Sizzle! Crack!

A glowing, light blue glyph materialized beneath him, intricate and pulsating with energy. He felt it again—the same coursing power, surging through his body like an unstoppable current. His breathing slowed as he opened his eyes.

But the world wasn't the same.

Everything around him had dissolved into darkness. A void stretched infinitely, filled with countless stars that twinkled faintly in the nothingness. The space was serene yet overwhelming, an expanse that seemed to whisper both calm and chaos.

Tick-tock.

The sound echoed in the void, faint yet clear. Seijuro froze. It was the same sound he had heard before—the rhythmic ticking of time, relentless and haunting.

Tick-tock.

Again, the sound reverberated, louder this time. He began moving, his body propelled forward, though he wasn't walking. The stars around him streaked past, moving faster than light, until everything stopped abruptly.

Before him was something incomprehensible—a vortex of swirling nothingness and everythingness at once. It lacked color and light yet somehow radiated an immense presence. It was a void that defied logic, embodying concepts that no mortal mind could grasp.

And yet... it called to him.

Seijuro extended a hand toward it, compelled by an instinct he didn't understand. The vortex seemed to pulse in response, as though acknowledging his approach. But just as his fingertips grazed the edge of the void—

"ISNMQOFN!"

A cacophony of voices erupted, alien and incomprehensible. The sound wasn't loud, yet it pierced his mind, resonating with an overwhelming intensity. Though he couldn't understand the words, the meaning was clear: You are not allowed. Go back.

"Ngh!"

Pain wracked his body as if every muscle, bone, and nerve were being twisted and pulled. He clutched his head, collapsing to the ground as the stars and void around him shattered like fragile glass.

When he opened his eyes again, he was back in the training ground, gasping for breath. His hands trembled as he pressed them against the ground, sweat dripping from his forehead.

"Why... does it hurt now?" he muttered, his voice shaky.

During the fight with Toji, the energy had flowed freely, unrestrained, and painless. Now, it felt like his body was rebelling against it, resisting his attempts to control it.

The only explanation he could come up with was his injuries. "It's because I'm still recovering..." he reasoned, though the answer felt incomplete.

His mind returned to the vortex. That vast, unknowable void had felt... different. Was that his Domain Expansion? Could it have been Unlimited Void? It made sense—it was a star-filled space, similar to what Satoru would manifest in the future.