The maintenance aisle after the duct was cooler, but the cool was a lie.
Cool could feel like relief.
Relief was poison.
Mark kept moving like the air was still trying to kill him—because it was. The Underworks didn't need blades to kill. It needed ceilings and humidity and narrow lungs.
Inhale—two shallow steps.
Exhale—two.
The "two" was thin. Posture stole volume. The cracked rib punished expansion where the stiff board pressed under belt wrap. The courier tube jammed into the same wrap pressed too, a hard cylinder that made every hip turn cost.
The left shoulder bled and failed. The joint slipped under any tug and refused clean alignment. The arm was weight now, not tool. The burn under bandage pulsed whenever the shoulder shifted, as if skin could remember fire and decide to report it again in wet air.
The right hand cramped on the falchion handle. The thick grip and leather wrap helped friction, but his dominant fingers still tried to open by fractions. He didn't fight the spasm with strength. Strength was not reliable.
He fought it with structure.
He pressed the handle into the bracer and forearm and used wrist angle like a clamp.
Ugly.
Necessary.
Latch was behind him, dragged more than walking. The injured knee wrap was dark and wet. The ankle chain scraped stone. The wet breathing was close and loud in the low aisle, a sound that could be both a lifeline and a countdown.
Mark kept the collar chain wrapped once around his left wrist and used the hook tool as a towing handle through a chain link, pulling Latch with the right side so the bleeding left shoulder didn't have to do it.
The chain bit raw skin anyway.
Wet sting spread.
He didn't stop.
Stopping was how the engine finished you.
The aisle ran into a junction where heat licked the stone.
Not open furnace heat.
A vent warmth, dry and sharp, leaking from a grated slit in the wall. The smell was ash and metal, cleaner than rot, and it made the lungs want to inhale deeper by reflex.
Deep inhales were expensive.
Deep inhales made the rib scream.
Deep inhales also tempted the engine into misreading: air feels better, maybe danger is gone.
Danger was never gone.
Mark made the corridor hostile with sound.
He dragged the falchion flat along the wall rib for half a breath—rasp—then lifted it.
The rasp wasn't intimidation.
It was a reminder to his own body: don't believe in quiet.
Behind them, a muffled sound traveled through the duct system—metal on metal, a grate shifting. The pursuer in the duct had found the hinge. He was coming.
Mark didn't look back.
Looking back was time.
Time became stillness if the body hesitated.
Stillness killed.
He chose the next corridor by airflow.
The vent warmth meant a service artery ran parallel—one that fed the furnace ducts and drained them. Those corridors had two advantages: noise from machinery and heat that discouraged people from lingering.
Lingering was stillness.
Stillness killed.
He moved into the warmth.
Inhale—two shallow steps.
Exhale—two.
The corridor narrowed and the ceiling dropped again, forcing the helmet-less hunch. The duct had stolen his helmet for the moment; he had dragged it behind through the grate drop, but it had become a liability in tight spaces. Now his skull was bare again, a soft target.
He didn't fix that yet.
Fixing gear was time.
Time was death.
The corridor's floor changed texture—metal grating in sections, then stone, then grating again. Under the grates, hot air moved, a steady dry current. The current carried sound too. Every clink traveled.
Mark used that.
He let the chain on his forearm clink once against the wall seam.
Clink.
A small honest sound that demanded verification.
The pursuer behind, hearing it through duct and corridor, would commit.
Commitment meant movement.
Movement meant threat.
Threat kept the drain from steepening when the corridor's warmth tried to feel like shelter.
Latch coughed behind him, wet and sharp.
The cough shook the injured knee and threatened to fold him into a kneel. Kneeling on a grating corridor was stillness disguised as posture.
Mark tightened the collar chain on his wrist and towed with the hook tool, forcing Latch into micro steps even if those steps were half drags. He didn't allow a full stop.
Inhale—one.
Exhale—one.
The breath count shrank, not panic—air and posture. The engine tightened anyway, because the corridor's rhythm had become too consistent.
Consistency was another lie of safety.
Mark broke consistency by changing the corridor.
He didn't run forward.
He turned into a side recess.
Not a hide.
A machine pocket.
The recess held maintenance tools: a hanging coil of chain, a wooden brace bar, and an iron ring bolt mounted in the wall for pulling grates.
The air in the pocket was hotter, closer to a vent outlet. Heat made sweat immediate. Sweat made grip worse. Heat also made the pursuer hesitate at the threshold because heat was uncomfortable even for professionals.
Mark didn't intend to live in the pocket.
He intended to make it a trap.
He already had a short chain wrapped on his left forearm from earlier fights. He had a hook tool. He had learned vertical doctrine from the disposal pit: hooks and edges. Now he needed a horizontal version.
Chain and hook trap.
Not to win.
To refill.
Refills were not comfort. They were borrowed function. His body was failing. The left shoulder was failing. The right hand cramped. Breath was becoming the limiter.
He needed a refill on command.
He needed it without a clean duel.
He built it with environment.
He hooked Latch to the wall seam first.
Not to abandon.
To keep him from being knocked into the corridor center.
Mark pressed Latch into the narrowest line beside the recess entrance and wrapped the collar chain around the wall ring bolt once, loose enough not to choke, tight enough to keep Latch upright and anchored if a body slammed him. Latch trembled, wet breathing loud. The injured knee shook.
Mark didn't comfort him.
Comfort was time.
Time was death.
He worked.
He grabbed the hanging coil of chain with his bracer and forearm—no fingers—and let a length drop to the floor with a controlled clatter.
Clatter was dangerous because it signaled position.
Clatter was also bait.
Bait was how you forced a pursuer to step where you wanted.
He didn't need a whole coil. He needed a line.
He threaded the chain across the corridor mouth at ankle height, hooking one end to the ring bolt in the pocket and the other end to a low floor grate bracket opposite.
A low trip line.
Not to trip randomly.
To trip at the worst moment: when a man entered, committed, and couldn't recover because the floor was grating and the air was hot and the corridor was narrow.
Trip lines didn't kill by themselves.
They created falls.
Falls created stillness.
Stillness killed Mark.
But for enemies, falls created opportunities: heads hit edges, bodies fall into vents, breath gets stolen by heat and pressure, and Mark could claim indirect kills if he forced them.
He needed the fall to become death.
So he added the second layer.
The hook.
He jammed the hook tool into the floor grating seam beside the vent outlet, not as a tool he held, as a fixed tooth. The hook tip caught a grating rib. He wedged it in place with the wooden brace bar—wood against metal—to keep it from being pulled free easily.
Now there was a tooth at shin height near the vent outlet.
If a man tripped and fell forward, his shin or knee would strike the fixed hook tooth and be pinned or torn. The fall would become a collapse, not a stumble recovery.
Collapse near a vent outlet meant hot air in face, breath stolen by heat and posture.
Breath stolen meant panic.
Panic meant poor recovery.
Poor recovery meant the next impact could kill.
Mark didn't have time for elaborate.
He made it simple: trip + tooth + heat.
Trap reliance increased heat.
He knew the cost already. Standing near vent outlets heated his body and made palms sweat, worsening grip.
He accepted it because he needed refills.
He made one more modification.
He used chalk.
Not for magic.
For traction.
He crushed a chalk stick in his right palm against the falchion handle, turning it to dust that coated damp leather. The dust increased friction slightly. It also made a powder when he slapped it onto the grating just beyond the trip line.
Chalk on metal grating made it slick in a controlled patch.
A man stepping in would either trip on the chain or, if he avoided the chain by lifting, slip on chalk.
Lifting exposed weak knee angles. Slipping made recovery harder.
Either outcome pushed the pursuer toward the vent tooth.
Mark stepped back into the recess and waited without being still.
Waiting was the most dangerous action he could take.
The engine hated waiting.
Waiting felt like calm.
Calm killed.
So he waited in micro steps.
Feet shifting inches.
Breath count kept at two by force.
Inhale—two shallow steps.
Exhale—two.
He kept the world hostile with small sounds: chain clink against ring bolt, falchion rasp once against wood brace, Latch's wet breathing and ankle chain scrape.
He listened.
The pursuer's presence arrived as sound first.
A metal scrape at the duct grate.
Then boots on grating.
One set.
Not a squad.
A cutter.
The one who had followed them through the furnace duct.
He stepped toward the pocket mouth cautiously, but caution in a narrow heated corridor was still commitment. His breath was controlled through cloth. His tools clinked—something metal, likely a hook or short spear.
He spoke, clipped, to someone farther back.
"Found them."
A reply echoed faintly through ducts.
"Hold. Don't die."
Professional.
Mark's sternum tightened anyway. The drain tested the moment because the pursuer's calm made the corridor feel managed.
Managed danger tasted like safety to the curse in the wrong way.
Safe was poison.
Mark refused by making danger immediate.
He kicked the loose end of the chain line once so it rattled.
Rattle.
The sound acted like a mistake.
Professionals verify mistakes.
The cutter stepped in.
His boot crossed the trip line.
The chain caught his ankle.
Not hard enough to yank him backward.
Hard enough to make his next step wrong.
His weight shifted forward.
He tried to recover by lifting the other foot.
Lift on grating was slow.
Lift also changed balance.
He caught the chalk slick patch with the lifted foot on the way down.
The foot slipped.
His center dropped.
His shin slammed forward toward the vent tooth.
The hook tooth caught flesh and cloth at shin line and pinned.
The cutter grunted sharply and went down on one knee.
Not dead.
Collapsed.
Close to the vent outlet.
The vent's hot breath blasted into his face as he tried to rise.
Hot air stole the next inhale.
He coughed.
Coughing in hot air stole more breath.
His recovery failed.
Mark moved.
Not to duel.
To finish by consequence.
He stepped out of the recess and slammed the falchion's flat into the cutter's head line—compact, downward, using weight rather than finesse. The grating under the cutter's hands made his arms slip. He couldn't brace.
The impact crushed.
The cutter went limp.
Blood hit grating and ran into the vent gaps.
Heat slammed through Mark.
Refill.
Breath opened full.
Tremor vanished.
The left shoulder still bled and failed. The rib was still cracked. The dominant hand still cramped. The breath limiter of the Underworks still existed.
But alignment returned for a window.
Mark used the window immediately.
He didn't stand over the corpse.
Standing would become stillness.
He stripped the trap fast.
Trap reliance increased heat, and heat was already soaking his cloth. He could feel sweat making grip worse. He couldn't linger.
He unhooked the chain trip line from the far grate bracket with the hook tool and yanked it back into the recess, letting it clatter.
Clatter was bait again.
Bait meant more bodies would commit to the corridor mouth.
He needed that.
He needed moving threat to keep the drain from steepening after the refill window ended.
He dragged the cutter's body partially into the corridor center—not out of respect, out of geometry. A body in a narrow corridor was an obstacle. Obstacles forced pursuers to slow. Slowing near a vent tooth and chalk slick patch was dangerous.
Danger was his ally now.
He towed Latch off the ring bolt anchor, wrapping the collar chain back around his left wrist, using the hook tool to tow with the right side to spare the failing shoulder.
They moved out of the recess and down the corridor, leaving behind the vent tooth and chalk patch and chain line, but not leaving it passive.
He kept the trap alive.
He left the hook tooth wedged.
He left chalk slick patch on the grating.
He left the corpse as obstacle.
He left a loose chain coil half-visible in the recess, like a promise.
Promises drew verification.
Verification drew boots.
Threat stayed present.
The corridor ahead bent and narrowed into another duct throat.
Not as hot as the furnace duct, but close enough that the air dried and stung. The heat didn't roar. It pressed. It made sweat immediate. Sweat made hands worse.
Trap reliance increased heat.
He could feel it now: the skin under bracers damp, palms slick, the leather wrap on the falchion handle softening again.
His dominant hand cramped harder after the refill window ended, as if the body resented being asked to function in heat without a refill.
He pressed the handle into forearm again, using bone clamp.
Latch dragged, wet breathing loud.
Behind them, the corridor answered.
Boots.
More than one set.
Two voices, clipped, in the vent corridor behind.
"Trip."
Another answered.
"Hook tooth."
They had found the trap.
Their voices weren't panicked.
They were solving.
"Cut it," one said.
"Don't step," the other replied.
They were adapting.
A trap that worked once could fail the second time.
Mark didn't wait for them to cut it clean.
He used the time it bought and moved deeper, but he also kept one ear on their problem-solving because the trap's value wasn't only in kills.
It was in forcing them to stop being calm.
Calm was how they killed him without touching.
If they were forced to deal with a vent tooth and a slick patch and a corpse in a narrow heated corridor, their calm would crack into urgency.
Urgency meant noise.
Noise meant threat.
Threat meant the drain stayed at bay even in low ceilings.
A shout came, suppressed.
"Watch the chalk—!"
A boot slipped anyway.
A metal clink.
A brief curse swallowed.
Then a heavier thud as someone collided into the wall rib.
Not a fall into a pit.
Not a kill yet.
But chaos.
Mark kept moving, dragging Latch.
Inhale—two shallow steps.
Exhale—two.
The corridor began to climb slightly—ramp upward—toward a higher service spine. Climbing in Underworks meant more breath cost. The oxygen pinch returned by degrees.
Latch coughed again, wet and deep.
Mark forced him to keep moving through the cough by towing with the hook tool and collar chain, never allowing Latch to kneel fully.
Micro steps.
Always micro steps.
The left shoulder bled. The joint slipped. Blood warmed cloth. The cracked rib stabbed with the hunch. The courier tube jammed in belt wrap pressed.
He kept moving.
Behind, the trap delivered its second consequence.
A louder thud.
A body hitting grating near the vent outlet.
A short strangled sound.
Then silence.
Not safe silence—dead silence.
Mark hadn't swung.
Mark hadn't touched.
But the trap had been built to make the corridor kill.
Trip line.
Slick chalk.
Vent tooth.
Corpse obstacle.
Heat.
If a man fell wrong, the vent outlet could steal breath long enough for the body to stop recovering.
If the body stopped recovering, a head could hit grating.
If the head hit grating and the body went still, death was plausible.
Mark had set that chain of consequences on purpose.
The engine acknowledged it.
Heat slammed through Mark again.
Refill.
Breath opened.
Tremor vanished.
Indirect kill credit.
Trap kills refill reliably.
That was the board-state change: he had found a method to obtain refills without engaging in clean duels—by building lethal geometry and letting pursuers die inside it.
He used the refill immediately to move faster up the ramp without sprinting, short flat steps, towing Latch with more control. He also used it to re-seat the helmet on his head as he passed a wider pocket—helmet dragged earlier now re-collected from his belt or trailing? He had been dragging it; during trap setup he might have secured it. In refill window he could press it back on, but in narrow passages it may snag. He chose not to now; leave for later.
The corridor ahead narrowed again, and the heat increased.
The vent spine they were following led toward a hotter sector—furnace-adjacent ducts—because Underworks and furnace infrastructure intersected.
Heat was dangerous now.
Heat didn't just make sweat.
It stole oxygen by making breaths shallow and fast.
It made the cough reflex more likely.
It made Latch's wet breathing worse.
It also made the trap method riskier, because heat damaged his materials.
Chain heated.
Chalk caked.
Wood brace charred.
Oil evaporated.
Traps could fail.
The pursuers behind knew it too.
A voice echoed through the vent corridor, clipped and calm again now that they had adapted.
"Don't follow into vents."
Another answered.
"Flush him out."
Flush him out meant they would stop committing to the exact corridor where his trap lived. They would reroute, cut ahead, meet him in a place where heat and low ceiling would do the killing without giving him an easy trap lane.
They were learning.
Mark was learning too.
He didn't need traps to be clever.
He needed traps to buy breath and alignment.
But each trap burned resources.
Each trap increased heat exposure.
Each trap moved him closer to the limit where his dominant hand would fail from sweat and spasm.
And he could feel that limit already: the falchion handle rotating by fractions more often, fingers cramping harder, pain blooming under the leather wrap.
He kept moving anyway.
Because the alternative was being held in a low wet corridor without a refill and without a trap and without breath.
The ramp ended in another junction, and above, through a grate, he could hear a different sound: water moving faster—sluice flow—suggesting a control corridor ahead.
Good.
Water meant noise and physics changes.
Bad.
Water meant slip and breath risk.
Everything down here had two edges.
Mark tightened the hook tool's hold on the collar chain link and towed Latch into the junction without stopping.
Behind them, the vent corridor fell quieter for a beat as the pursuers chose alternate routes.
That quiet beat was deadly.
The drain tightened instantly, steep curve threatening to return.
Mark refused by making his own threat.
He kicked a loose metal ring into the duct seam so it clattered and rolled.
Clatter.
A moving sound line that would demand verification.
Verification would pull boots.
Boots would keep threat present.
Threat would keep the drain from finishing him in the moment the world felt empty.
And as the ring rolled and the sound traveled down the hot vent spine, Mark felt the trap method's next cost forming—not in pursuers' voices, but in the heat itself: the air ahead was hotter, the ceiling lower, and the next mistake wouldn't be a hook catching his belt ring.
It would be his own hand finally opening.