The sky over Hinomori was tinged with red that afternoon.
It wasn't sunset.
It was fear.
Sirens echoed through the narrow streets as people ran aimlessly, stumbling over their own feet. The shop windows reflected a shapeless shadow that crept between the buildings—something that shouldn't exist. Something born when human emotions crossed the line.
"A Mugen… here?" a man murmured, falling to his knees before disappearing in a choked scream.
Atop a residential building, 15-year-old Raizen Akatsuki watched everything with clenched fists. His school uniform was crumpled, his backpack thrown to the side. He breathed heavily, not from physical exertion, but from the pressure crushing his chest.
He felt it.
He felt the people's panic.
He felt the despair.
He felt the pain.
"Damn it…" he whispered. From a young age, Raizen had always been like this. Too sensitive. He would cry when someone got hurt, even if it was a stranger. Adults told him he needed to "harden his heart." His classmates called him weak.
And in that world… the weak didn't survive.
The Mugen advanced down the main street, its body composed of pulsating shadows and distorted faces, all frozen in expressions of anguish. Each step made the ground tremble, fueled by the surrounding emotions.
"Level three evacuation!" shouted a distant loudspeaker. "Await the Kiba Holders!"
Raizen gritted his teeth.
Waiting… always waiting…
He remembered his mother's face that day, years ago, when a Mugen appeared too late to be contained. He remembered the feeling of helplessness, the warm hand dripping blood between her fingers.
"I hate this…" his voice faltered. "I hate not being able to do anything."
A scream echoed below.
Raizen looked and saw a girl trapped under rubble, crying, unable to move as the Mugen slowly approached.
His heart raced.
"No… no…" he took a step forward without thinking.
A part of him screamed to run. Another, stronger part, pushed him forward.
If I do nothing… someone will die again.
Raizen jumped from the building.
The impact was brutal. Pain shot up his legs, but he didn't stop. He ran to the girl, ignoring the screams around him.
"Hey! Stay with me!" he said, trying to lift the debris.
The Mugen noticed.
Its "eyes" turned to Raizen, and a roar ripped through the air. A wave of pressure threw him to the ground.
"Gah…!" he spat blood.
The shadow advanced.
Raizen felt something different. It wasn't fear.
It was a deep warmth in his chest. A pain that didn't destroy him—it pulled him forward. The voices, the feelings, everything connected within him.
"I… I won't…" he forced himself to his knees. "I won't let this happen!"
The ground beneath his hand cracked.
A soft, almost transparent light enveloped his arm. It wasn't violent like the Kiba he'd seen on television. It was calm. Trembling.
A blade began to form.
Not of hatred.
Not of anger.
But of empathy.
"This is… a Kiba…?" Raizen's eyes widened.
The spirit blade was simple, slightly curved, pulsing like a living heart. Each beat echoed with the surrounding emotions.
The Mugen hesitated.
Raizen stood, his body trembling.
"I feel everything you feel…" he said, staring at the monster. "And that's exactly why I'm going to end this!"
He lunged forward.
The instant the blade touched the shadow, a flash exploded across the street. Mugen let out a different kind of cry—not of fury, but of liberation—before dissolving into particles of light.
Silence.
Raizen fell to his knees, Kiba dissipating like smoke.
"Did I succeed…?" he murmured, before everything went dark.
When he opened his eyes, he saw silhouettes around him. Warriors dressed in black cloaks, Kiba gleaming in their hands.
One of them spoke, in a serious voice:
"A Kiba awakened without training…"
"And on top of that… with empathy?"
Raizen tried to move, but his body wouldn't respond.
Before fainting again, she heard the words that would change her life forever:
"This boy is going to turn the world upside down."