Time passed in a flash.
Five days later.
"Castle Space. Forging Room"
Mercer took off his gas mask and looked at the reddish-gold alloy in the three molds inside the forge. It had a semi-solid texture.
"The alloy has finally been smelted successfully. Now, let's get started."
He poured the semi-solid alloy into a cooling pool.
Hiss—
Billowing white mist rose.
A moment later,
three dark iron ingots appeared. Mercer picked up the largest with iron tongs and put it back in the furnace to heat. Before long, he placed the glowing-red ingot on the anvil.
Clang—
He raised his forging hammer and began to strike. By repeatedly hammering the alloy, Mercer worked its internal grain into order and changed the metal's internal structure.
He entered a state of Unity of Heaven and Man.
With Observation Haki sensing the internal grain, he struck with the hammer in his hand with unerring precision, arranging the alloy's patterns and gathering its spirit as he played a flawless melody.
Everything flowed as smoothly as water.
The alloy was hammered into a long bar, folded, then hammered again. As time passed, its internal patterns were integrated, and the material's spirit began to gather. A weapon shaped like a long sword took form.
He struck it again and again, shaping it while sensing how the patterns inside connected. When its spirit had gathered to its peak,
he picked up the sword and plunged it into the springwater pool.
"Quenching."
Hiss—
A violent cloud of steam rose.
Its spirit finished gathering at that moment, then stabilized.
Mercer lifted the blade and examined it, satisfaction gleaming in his eyes.
Then he put it back in the furnace to heat it.
"Tempering."
Once that step was complete,
Mercer set the long sword aside to cool.
Then he continued