The deeper they went, the stranger the air became.
It was a sticky, humid heat, like stepping into the esophagus of a giant beast that had just regurgitated its meal. Mixed with the pungent stench of heavy engine oil was a sickeningly sweet smell that made their scalps tingle—the smell of corpses.
"There's light ahead."
Colonel Ka huddled behind the tank's rear, peeking around like a startled marmot.
The tunnel suddenly opened up at its end, revealing an enormous underground workshop. Thick copper pipes, dense as a spiderweb, pulsed overhead like blood vessels before feeding into the intricate assembly lines below. Steam shrieked and pistons rose and fell. This dead city, dormant for a thousand years, was somehow still operating on its own.
"Stop." Hiruzen suddenly raised a hand, halting the group.
He narrowed his eyes and stared fixedly at the "semi-finished products" hanging from the assembly line.
They were no longer mere bronze frames. The joints of these puppets were wrapped in a grayish-white layer of flesh that was still faintly wriggling. It was skinned muscle tissue, brutally grafted onto metal skeletons with rivets and tubes.
"Biological... living tissue grafting?" Gaara's pupils shrank as his stomach churned.
"Wooo—!!!"
A shrill whistle suddenly exploded through the air, like the morning bell announcing the start of work in hell.
The entire workshop instantly came "alive." Conveyor belts accelerated into a mad rush, and gears meshed frantically with ear-piercing grinding noises.
"Click, click."
The clasps on the hanging racks sprang open in unison. Hundreds, perhaps thousands, of "semi-biological puppets" dropped to the ground like dumplings into a pot. They landed on all fours, purple exhaust spraying from the tubes on their backs, then raised featureless faces—except for metal jaws split all the way to their ears, packed with spinning meat-grinding gears.
"Open