The subterranean Maglev Tunnels of Sector 12 were a graveyard of silence.
This was the deepest part of the city's transport infrastructure, a network of concrete arteries that ran hundreds of feet beneath the surface. It had been abandoned years ago when the Guut infestations made public transit a death sentence. Now, the tunnels were dark, damp, and smelled of ozone and stagnant water.
Eren walked along the central rail.
He wasn't running. Not yet.
He wore his standard light-recon armor, the yellow accent lines glowing faintly in the dark. His vibro-daggers were sheathed at his hips.
He stopped, looking down at his right leg.
It looked normal. The boot fit perfectly. The knee flexed without a click or a pop. But to Eren, it felt... foreign. It was the leg that the Re-Genesis tank had grown for him from scratch. It was brand new meat, brand new bone, brand new nerves.
He tapped the toe of his boot against the steel rail. Clink. Clink.
"You holding up down there, buddy?" Eren whispered to his own leg. "Don't quit on me."
The phantom sensation of the Mimic's hand gripping his ankle flashed through his mind—the crushing pressure, the wet tearing sound, the agony.
Eren shook his head violently, forcing the memory back into the box. "Nope. Not today. Today is just pest control."
He tapped his earpiece. "Command, this is Agent Eren. I'm in the Sector 12 Tunnels. It's quiet. Too quiet. Just me and the rats."
"Copy, Agent Eren," the dispatcher replied. "Sensors show a high-velocity signature moving toward your position from the North Junction. Class 5. Be advised, it's fast."
"Fast?" Eren smirked, adjusting his goggles. "I like fast."
A sound echoed down the tunnel.
SKREEEEEEEE.
It was the sound of metal being shredded.
From the darkness of the North Junction, two glowing yellow eyes appeared. They were low to the ground, bobbing rhythmically.
The creature burst into the dim light of the overhead emergency bulbs.
It was a Class 5 Guut: Raptor-Type.
It was a sleek, aerodynamic horror designed for one thing: velocity. It stood on two powerful hind legs, its body covered in smooth, obsidian scales that reduced wind drag. It had a long, whip-like tail for balance and aerodynamic fins protruding from its skull. Its arms were short but ended in curved, sickle-claws.
It didn't roar. It hissed, its throat vibrating.
It saw Eren.
It didn't hesitate. It launched itself forward.
The Guut moved like a missile. It covered the fifty yards between them in under two seconds, kicking up a cloud of dust and sparks as its claws scraped the rails.
Eren watched it come. His eyes tracked the movement.
"Okay," Eren breathed. "Let's see what the new leg can do."
The Guut lunged, its sickle-claws aiming for Eren's throat.
ZZZT.
Eren vanished.
He didn't teleport. He simply accelerated.
He reappeared ten feet behind the Guut, leaning casually against a rusted support pillar.
The Guut's claws slashed empty air. It skidded to a halt, turning its head in confusion. It hissed, looking around.
"Over here, ugly!" Eren called out.
The Guut whipped around, screeching. It charged again, faster this time.
Eren waited until the last possible microsecond. He could see the saliva dripping from the beast's mouth. He could see the hunger in its eyes.
Move.
Eren engaged the Gold Fluid.
His body became a blur of yellow light. He sidestepped the Guut's charge with the grace of a matador. As the monster passed him, Eren extended his leg and kicked the beast in the side.
THWACK.
The impact sent the Guut spinning sideways, crashing into the wall of the tunnel. Concrete cracked.
Eren landed on the balls of his feet, bouncing lightly. He looked down at his right leg. No pain. No stiffness. The new muscle fibers were responding perfectly. In fact, they felt... springier.
"Ha!" Eren laughed, the fear in his chest evaporating. "Factory fresh!"
The Guut shook off the dust and stood up. It was angry now. The fins on its head flared open, and it let out a sonic screech that echoed painfully in the confined space.
It began to run along the walls.
Its claws dug into the concrete, allowing it to sprint horizontally along the curved ceiling of the tunnel. It was using the environment, gaining momentum, circling Eren like a shark in a tube.
"Okay, you want to play track and field?" Eren grinned, pulling his goggles down over his eyes. "Let's run."
Eren took off.
He sprinted down the tunnel. The Guut followed, running on the ceiling directly above him.
The chase was on.
The world blurred into streaks of grey and black. The wind roared in Eren's ears. He wasn't even at full speed yet; he was cruising at maybe 300 miles per hour, testing the creature's limits.
The Guut dropped from the ceiling, aiming to tackle Eren.
Eren sensed the change in air pressure.
"Phase Shift," Eren muttered.
He vibrated his molecules. His body became intangible for a split second.
The Guut passed right through him.
It was like a ghost passing through a wall. The Guut crashed into the tracks below, tumbling over itself.
Eren solidified instantly. He skidded to a stop, turned, and waited for the creature to recover.
"Is that all you got?" Eren taunted, crossing his arms. "You're a Class 5? My grandma runs faster than you, and she has a hip replacement."
The Guut shrieked, humiliating rage fueling its movements. It gathered itself, crouching low. Its leg muscles bulged. It was preparing a max-speed blitz.
It launched.
This time, the Guut was barely visible. It was just a black streak of malice.
Eren's smile dropped. His eyes narrowed.
"Gold Fluid: Overdrive."
The yellow lightning around Eren's body exploded. The air around him ionized.
He didn't wait for the Guut to reach him. He charged to meet it.
They rushed toward each other like two locomotives on a collision course.
Ten feet before impact, Eren jumped.
He didn't jump over the Guut. He jumped onto the wall. He ran three steps up the vertical concrete, pushed off, and performed a corkscrew spin in mid-air.
He drew his vibro-daggers.
"Supersonic Spin Cycle!"
Eren became a golden buzzsaw.
He collided with the Guut mid-air.
SLASH-SLASH-SLASH-SLASH.
The sound was like a chainsaw cutting through wet wood.
Eren landed gracefully behind the Guut, sliding to a stop on one knee, his daggers extended to the sides.
Behind him, the Guut froze. It tried to take a step.
Suddenly, a dozen glowing yellow lines appeared on its obsidian scales.
SPLAT.
Black blood sprayed from twelve different wounds simultaneously. The Guut collapsed, its tendons severed, its armor sliced to ribbons. It writhed on the ground, unable to stand, unable to run.
Eren stood up and sheathed his daggers. He walked over to the crippled monster.
The Guut looked up at him, wheezing. Fear—pure, primal fear—was in its eyes. It tried to crawl away, dragging its useless legs.
Eren watched it. He thought about the Scrapyard. He thought about the feeling of helplessness when his leg was torn off. He remembered begging the Mimic to stop.
He looked at his new right leg.
He stepped forward and placed his boot on the Guut's head, pinning it to the ground.
"You know," Eren said softly, leaning down. "I used to be scared of being caught. I used to think that if I stopped moving, I'd die."
He applied pressure. The Guut whimpered.
"But I realized something in the tank," Eren continued, his voice losing its playful edge. "I don't run because I'm scared. I run because I can. And you?"
Eren's eyes flashed gold.
"You just ran out of track."
Eren vibrated his right leg.
It wasn't a kick. It was a jackhammer. He vibrated his foot at a frequency so high it turned the solid matter of his boot into a kinetic drill.
He stomped.
CRUNCH.
The vibration traveled through the Guut's skull, liquefying its brain instantly. The monster went limp, dissolving into black smoke and ash before the echo of the stomp even faded.
Eren stood alone in the tunnel.
He took a deep breath, inhaling the ozone and the dust. He checked his heart rate. It was barely elevated.
He looked down at his right leg again. There was not a single scratch on the boot.
"Works perfectly," Eren whispered.
He reached up and tapped his earpiece.
"Command, this is Agent Eren," he said, his voice back to its usual cocky drawl. "Target neutralized. Sector 12 is clear. Also, tell the maintenance crew there's a mess on Track 4. I might have... overdone it a little."
"Copy, Agent Eren. Extraction team is on the way."
"Take your time," Eren said, stretching his arms. "I might jog back. I need to break in these boots."
He turned and looked down the endless, dark tunnel stretching toward the city center.
With a grin, Eren dropped into a sprinter's stance.
"On your marks... get set..."
ZOOM.
A golden streak of lightning tore through the darkness, leaving nothing but a sonic boom and swirling dust in its wake. Eren was back. And he was faster than ever.