The Emiya household had too many rooms for just two people.
Dust still clung to the corners. The silence hung heavy in the walls — not lifeless, but waiting. Like the house itself was holding its breath.
Kiritsugu didn't bother cleaning much. Not yet. Not when his body still screamed every time he stood too long. Not when every step reminded him of what he had given up to save a boy from the fire.
Shirou, though…
Shirou never stopped moving.
They were strangers at first.
A man with a broken body and too many regrets.
A boy who had walked through fire and left half his soul behind.
Kiritsugu had given him a name: Shirou Emiya.
The boy accepted it without hesitation. He didn't remember his old one anyway.
The silence between them wasn't cold — just cautious.
But it didn't last.
They cooked together. Cleaned. Trained. Spoke little, but existed in a rhythm only two survivors could understand.
Shirou's quirk emerged three days after the fire.
Not with rage.Not with fear.
But with resolve.
He'd been dreaming of the same place each night:
A vast, lifeless plain under a smoky sky. The ground scattered with swords — cracked, glowing, alien. Some ancient. Some familiar.
And in the center of it all burned a flame.
Not on his skin, but inside his chest. A white-hot fire that pulsed with memory, pain, and clarity.
It wasn't just a source of power.It was a forge.
Kiritsugu recognized it immediately.
A rare quirk — one with no proper classification.
The doctors had been confused.
His quirk didn't fit into a neat category.
Not a simple emitter.Not transformation.Not even an evolution-type.
It was something deeper — more primal. A spiritual quirk, extremely rare. Born not just of genetics, but will.
Projection? Yes.
Enhancement? Possibly.
But deeper than that, it was spiritual.Internal. Willbound.
A dual-aspect quirk Kiritsugu named:
Soul Forge
Its function?
To create weapons from memory, emotion, and discipline — forged through the user's inner flame.
Not simple replication.Not copying.
Understanding. Internalizing. Becoming.
In other words:
A furnace that burned the soul to forge weapons of the mind.
Kiritsugu called it madness.But he also called it beautiful.
The fire inside Shirou wasn't physical.It was who he was.
Training began on the fourth morning.
Kiritsugu wheeled himself out to the yard, wincing with every bump of the stone.
Shirou stood barefoot in the grass, eyes
closed.
"Don't force it," Kiritsugu said. "Focus on the flame. On what's real."
Shirou took a slow breath.
He pictured a short blade — one from a book Kiritsugu had given him. A basic combat knife used in the Second Quirk War. Balanced. Simple. Meant to protect.
He reached inward.
The flame answered.
A ring of sigils formed in the air — geometric, rotating, ancient.
A pulse.
And then — the weapon appeared.
Rough. Flickering. Not fully stable.
But real.
Shirou gasped as his knees buckled. The blade evaporated.
Kiritsugu was beside him in a flash, catching him.
"You forced it," he said. "The forge doesn't accept lies."
Shirou panted. "But I remember it. I studied it."
Kiritsugu looked him dead in the eye.
"You can memorize blueprints all day. That doesn't mean you understand what a weapon is."
That became the core of Shirou's training.
Not summoning weapons.
Becoming worthy of them.
Every day, Kiritsugu taught him balance, control, and the cost of pushing too far.
Every night, Shirou studied — weapon schematics, combat history, metallurgy, martial forms.
His flame responded not to strength, but clarity of purpose.
If he doubted? It flickered.
If he lied to it? It burned him.
But if he believed—
If he truly understood what he was trying to create?
It answered.
One month in, a storm named Taiga Fujimura crashed into their lives.
She arrived with no warning, a grocery bag in one hand and a foot already halfway through the door.
"Kiri-chan!" she shouted. "What the hell is this? I leave town for one month and you adopt a fire child?"
Kiritsugu blinked. "…Good to see you too, Taiga."
She marched into the kitchen, dropped the bag, and turned to Shirou.
"You. Redhead. Name?"
"Shirou Emiya," he said.
She stared.
"…You named him already?"
"Yes."
"…I was gone for one month!"
Kiritsugu shrugged.
Taiga sighed, hands on her hips.
"Well. Guess that makes me your aunt, squirt."
Shirou raised an eyebrow. "Aunt?"
"You'll get used to it," Kiritsugu muttered.
That night, after Shirou went to bed, Kiritsugu sat on the porch.
The cool air stung his joints. His hands trembled faintly.
He closed his eyes—
And opened them when a familiar presence stepped out of the darkness.
Lady Nagant.
Still quiet. Still dangerous. Coat draped over her like a shadow.
"No rifle?" Kiritsugu said.
"Didn't think I'd need one."
They sat in silence for a moment.
"He's got a rare type," she said eventually. "Soul-forged. We haven't seen one like that since… ever."
"I know."
"The Commission's going to come sniffing."
"They won't find him."
"They always do."
Kiritsugu turned his head, eyes sharp.
"If they come for him, I'll burn it all down."
Nagant exhaled, then nodded once.
"Spoken like a man with nothing left to lose."
"I've got him now."
That shut her up.
She left without another word.
Upstairs, Shirou sat alone with a flickering blade in his hand.
The weapon was imperfect — edge not quite formed. But it pulsed gently in sync with the flame inside him.
He stared at it, thinking of the fire, the man who pulled him from it, and the smile that had become his wish.
'One day… I'll be strong enough to smile like he did.
And I'll save someone the way he saved me.'
He closed his eyes.
The forge burned silently.