The forge dimmed, leaving only the pulsing glow of Yggdrasil's veins and the suspended hologram of Karl's incomplete body.
His armor was nearly finished — but it still lacked one thing: a bridge. Something that could connect the human soul to the divine machine.
Itsuki Kurogane and Ayaka stood before a pedestal of floating runes — their son's half-formed body suspended behind them, glowing faintly as divine sap threaded through his veins of nanite steel.
But his heart was still missing.
Hephaestus folded his arms.
Hephaestus: "The frame will not respond without a regulator — something to balance the human and the machine."The framework is sound, but without a regulator, he'll never control the transformation. The nanites would rip his soul apart before his heart even starts beating."
Thanamira: "And to keep the soul stable, he must have a medium — a point of translation between mortal instinct and divine mechanism. "Then we must give him a core worthy of both your craft and his lineage."
Itsuki and Ayaka exchanged a glance — and for the first time since their deaths, they genuinely smiled.
Ayaka: "He always loved machines that transformed. Even when he was little, he'd pretend he had a belt that could turn him into something greater."
Itsuki: "Then let's make him that belt… but one that answers to his heart, not just his hand."
Itsuki (smiling faintly): "A transformation device. Just like the ones he loved as a kid."
Hephaestus blinked, curious.
Hephaestus: "Transformation… device?"
Ayaka (grinning sadly): "You'll see."
With a flick of Itsuki's wrist, a dozen screens materialized around them — schematics written in glowing sigils and quantum circuits. Each new line etched into the air made the forge rumble as if the world itself acknowledged what was being born.
At the center floated the design:
a hybrid spinal harness, elegant yet brutal, like a mechanical spine wrapping around the waist — its core gleaming with crystalline gears.
Itsuki: "We'll call it the Drive Regulator. It won't just control his transformations — it'll stabilize his soul, balance the Engine and Gear within him."
Hephaestus: "Show me your intent, mortal. The forge obeys will, not blueprints."
Itsuki: "The base — a spinal harness, flexible but strong. We'll use carbon-titanium nanite mesh for mobility, reinforced with your divine micro-gears."
Hephaestus: "A hybrid of flesh and forge… fitting."
Ayaka stepped forward, her hands hovering over the chest cavity hologram. A translucent sphere formed — crystalline, humming faintly. Inside it, hundreds of micro-gears spun in perfect harmony.
Ayaka: "This will be the Gearheart Core. The source of his life force. I'll bind a fragment of my Engine Soul into it — a mother's will to protect."
Itsuki extended a finger, summoning sparks of dark-blue light that swirled into a disk.
Itsuki: "And at the core — the Gearheart. The center of everything. It'll contain your Soul, Ayaka. Your energy will flow into the nanites, giving him life."
Ayaka smiled through tears, pressing her glowing palm to the Gearheart's forming shell.
Within the transparent nano-crystal casing, micro-gears began to spin — delicate, eternal, powered by her essence. The hum was soft, almost maternal.
Ayaka: "Then every time he transforms, it'll be my heartbeat he feels."
The sphere pulsed, as if alive. The light from within turned from gold to soft azure. Its vibrations synchronized with Yggdrasil's heartbeat.
Thanamira's eyes widened.
Thanamira: "She's imprinting emotion directly into the lattice…"
Hephaestus (grinning): "Beautiful. Pure, efficient, irrational — just like mortal love."
Hephaestus nodded with a hint of reverence.
Hephaestus: "The Gearheart Core — living energy in mechanical form. A creation even I could not have imagined."
Then Itsuki stepped back, summoning a long, dark alloy cylinder into being — etched with runes that glowed along its length.Then Itsuki traced a glowing sigil along the projection of Karl's spine.
Itsuki: "And this will be the Torque Regulator — the Gear Drive Core. It'll run along his spine, distributing torque and stabilizing his nanite flow. My soul will anchor it."
The spine-like cylinder formed — a dark metallic alloy breathing with faint light. Each rotation emitted a low mechanical hum, steady and reassuring, like a heartbeat made of gears.
He pressed his hand against the cylinder, and a admiral flame passed from his chest into the device.
It whirred to life, humming with a rhythm that matched his heartbeat.
Ayaka: "Your soul for the Drive, mine for the Engine. Together, they'll form the Drive Regulator."
Thanamira (smiling faintly): "Husband and wife — turned into dual hearts of balance. Beautiful irony."
Ayaka reached for another component
A crank appeared on the waist segment — gear-shaped, elegant yet rugged.
Ayaka: "And this… this will be the Ignition Dial. His way of commanding his own destiny."
She rotated it gently; sparks of nanite light scattered like fireflies.
Ayaka: "A slow turn will activate his car form — a symbol of mobility, speed, progress. A rapid rotation, the mech — for defense and rescue. And a full turn…"
Itsuki: "…Overdrive Mode. When he needs to go beyond the limits of flesh."
Hephaestus raised an eyebrow.
Hephaestus: "You would let him wield power that could burn even divine steel?"
Itsuki: "He's our son. He's always been the type to break limits."
Ayaka: "Then we'll make sure it humbles him, too. If he goes too far, I'll be there in the feedback — to warn him."
Ayaka's soul fragment linked to the Dial, embedding within it a faint maternal signature. Whenever Karl would push too far, the system would tremble — a silent echo of her voice reminding him to stop.
At the core of the chestplate, the final piece emerged — a rotating semi-sphere of intertwining gears, spinning faster with each pulse of Yggdrasil's roots.
Itsuki: "Overclock Module. It'll activate when he uses everything — body, mind, soul. A final safeguard that turns desperation into strength."
Thanamira: "That's dangerous."
Hephaestus: "So was humanity."
Itsuki smirked faintly.
Itsuki: "He's our son. He was born chasing danger."
When all the components were laid out — the Gearheart Core, Torque Regulator, Ignition Dial, and Overclock Module — Hephaestus raised his hands.
The components drifted into alignment — waist chassis, spinal regulator, chest module — connecting with faint threads of divine energy. As they locked together, the glow intensified, casting radiant lines along the forge walls.
Melting the pieces into a cohesive form — a luminous belt-harness, sleek yet intricate, its gears shifting like breathing lungs.
Itsuki and Ayaka watched in awe.
Ayaka (whispering): "It's… perfect."
Itsuki: "No. It's him."
The device floated toward Karl's half-formed body, aligning itself around his waist and spine.
Energy conduits connected to his chest cavity, merging seamlessly with the Gearheart Core.
The forge rumbled as the Drive Regulator locked into place — and for the first time, Karl's body moved.
His fingers twitched, nanites sparking with faint cerulean light.
Ayaka gasped.
Ayaka: "He… responded."
The Drive Regulator pulsed once — a deep, resonant whirr that echoed through the entire Cradle.
Then it went silent. Waiting.
Hephaestus nodded slowly, impressed.
Hephaestus: "A mortal's dream, forged by gods and parents alike. Even among the Chosen, this creation will be one of legend."
Ayaka (whispering): "His bridge between man and machine… our parting gift."
Itsuki: "No. Our promise that he'll never be alone again."