Zack held his ground in front of the core access gate, and for one stupid, stubborn second he waited for the world to remember what it was supposed to be.
A friend. A mission. A clean line you didn't cross.
Sephiroth stood on the other side of him like a final answer.
The mako below kept roaring through its open channels, blinding and alive, throwing green light up the catwalks until everything looked surgical—bones and shadows and metal ribs. Heat shimmered off it in thick waves that warped the distance, so the far scaffolding wavered like it was trying to decide whether to stay solid or become a mirage. The whole chamber felt like it was breathing through machinery, each exhale grinding.
Zack's palms were wet inside his gloves. Not fear-sweat. Not entirely. Condensation too—metal sweating under pressure, the air so hot it couldn't hold itself together. The catwalk beneath his boots had a slickness to it that made every small shift feel like a warning.
Sephiroth's gaze slid past him to the access gate again—patient, almost reverent.
Zack lifted his chin. "Sephiroth."
The name didn't land the way it used to. It didn't snag him. It didn't pull him back. It just existed, bouncing off the calm in Sephiroth's face and falling uselessly into the roar.
Sephiroth's hand moved to the Masamune.
It wasn't rushed. It wasn't angry. It wasn't even dramatic.
It was ritual.
Gloved fingers settled on the hilt with the same care you'd use to touch something sacred, something you'd been taught to respect long before you understood why. Then the blade slid free—long and clean and impossible—and the sound it made wasn't a scrape so much as a note. A thin, bright line of music that cut through the engine-hymn below and made Zack's teeth ache.
The metal didn't just reflect the mako glow.
It drank it.
Zack's body reacted before his mind finished catching up. The Buster Sword came off his back like it weighed a lifetime—because it did, in a way—because Angeal's hand had been on it first, because promises had a mass, because legacy was heavy even when the steel was balanced.
He drew it with both hands, the blade's broad edge catching the green light in dull flashes, and when it cleared the sheath the air felt tighter—like the chamber itself had leaned in.
For a heartbeat, they just stood there.
Masamune, a surgeon's instrument.
Buster Sword, a door you slammed shut between the world and what it wanted to do to you.
Zack's throat worked around a swallow he didn't remember choosing. "Don't make me do this."
Sephiroth's expression softened, faintly—something almost kind trying to wear a face it didn't belong to.
Then he moved.
He didn't lunge.
He stepped.
One smooth, economical shift of weight, and the Masamune was already coming in, so fast it didn't look like a swing until the air split around it.
Zack met it on instinct, Buster Sword slamming into the arc with a clang that rang up his arms and into his shoulders like a bell struck too hard. Sparks snapped off the meeting point—orange against green—and the impact shoved him back a half-step, boots skidding on slick metal.
Sephiroth didn't give him time to recover.
Another cut. Then another. Different angles, different heights, each one precise enough to feel planned, as if Sephiroth had already mapped Zack's defenses and was now simply testing which part of him would fail first.
Zack blocked hard, the Buster Sword catching each strike with brute force and grit. He could feel the vibrations shudder through the blade into his bones. His wrists burned. His elbows jarred. Every parry felt like stopping a guillotine with your forearms.
"Seph—" Zack tried between impacts, breath coming fast now, ripped into pieces by effort and heat. "This—this is insane—"
Sephiroth didn't answer.
He didn't need to.
He fought like a surgeon. No wasted motion, no flourish meant for an audience. Just clean intent. Just cuts designed to separate things: tendon from bone, rope from rail, friend from friend.
Zack fought like a man on a ledge with someone he loved two inches from stepping off.
He pushed forward anyway, trying to close distance, trying to make it messy enough to break Sephiroth's calm. Trying to force a mistake out of him, because a mistake would mean he was still human.
Sephiroth gave him none.
The Masamune flicked in and out of range like a thought you couldn't catch. Zack caught one strike too late, the blade glancing along the Buster Sword's edge and shaving off a ribbon of metal that spun away into the air and vanished into the heat shimmer.
Zack felt it like a gut punch. Not the damage—just the implication.
He was being dismantled.
He planted his boots, shoved back with both hands, and for the first time Sephiroth's feet shifted—barely, a concession measured in millimeters.
Zack took that inch like it was oxygen.
He swung wide, not elegant, not pretty—heavy steel intended to end the conversation. Sephiroth pivoted, coat snapping in the hot air, and let the blade pass where he'd been, close enough that Zack felt the drag of displaced heat.
Zack's momentum carried him a fraction too far. His boot slid. The slickness bit.
Sephiroth's eyes narrowed, almost gently, like he'd just watched Zack trip on a stair and decided not to warn him next time.
The Masamune came in again—low this time.
Zack dropped his center of gravity, blocked with the Buster Sword's lower third, and the impact drove him backward across the catwalk. His boots squealed on wet metal. His shoulder clipped the railing, cold and slick under his glove, and for a second the roar below seemed to rise like it smelled blood.
Green light surged up through the grating, bright enough to make Zack's vision strobe.
He could feel the mako's heat through the soles of his boots now. Not just warmth—pressure. Like standing over an open furnace that also happened to be the planet's bloodstream.
"Stop," Zack hissed, not commanding, not pleading—just desperate. "Stop. Look at what you're doing."
Sephiroth's gaze flicked past Zack's shoulder to the access gate again.
Zack realized with a sick twist that none of this was the point.
Sephiroth wasn't trying to beat him.
He was trying to move him.
Like clearing debris off a path.
Zack tightened his grip, knuckles aching. He stepped in again, forcing his body through the fatigue, through the heat, through the way the chamber seemed to press down on his thoughts.
He swung. Sephiroth parried with a minimal tilt, steel kissing steel with that sharp, singing note again. The sound didn't echo like normal.
It threaded into the refinery hymn and made the hum feel… aware.
Sephiroth's eyes lifted slightly, as if he'd felt it too.
Then he turned his blade—not toward Zack's chest.
Toward the catwalk.
Zack saw the angle a half-beat late.
"No—"
Sephiroth's Masamune flashed, impossibly clean, and sliced straight through a thick support cable running along the side of the platform.
The cut was so precise it took a second for the cable to understand it had died.
Then it snapped.
The sound was a violent twang that shivered through the whole structure. The catwalk jerked under Zack's feet like a living thing startled awake. Bolts screamed. Metal plates buckled. A section of grating dipped hard, then tore loose, dropping away into the green glare below.
Heat surged up through the sudden gap like a breath from an open mouth.
Zack's stomach dropped with it.
His boot skidded. The world tilted. The railing blurred past his hand as the platform lurched and the slick metal decided it didn't want to be a floor anymore.
Zack threw himself sideways on instinct, fingers clawing for purchase.
His glove caught the railing.
It was wet. It was hot. It felt like grabbing the edge of a pan that had been sitting on a burner for hours, except the pain arrived a fraction late because adrenaline is a liar that loans you time and then collects with interest.
Zack's body swung out over the gap.
For one suspended, ridiculous moment, he saw everything beneath him: the open mako channels, the blinding river of green fire, the turbulence moving through it like muscle. It surged against the containment walls in luminous waves, and the light strobed across Zack's face like a warning lamp.
He could've sworn it surged harder right then—right at the moment his grip slipped a millimeter.
Like it was reacting.
Not to gravity.
To him.
To the panic spike, to the grief, to the frantic no no no that his mind screamed without words. Like the Lifestream wasn't just energy down there. Like it was listening. Like it was hungry for big feelings and didn't care where they came from.
Zack's forearm trembled as he hauled himself back up, muscles screaming. His boots scraped the grating, found purchase, slipped again, then finally bit. He rolled onto the catwalk on his side, coughing hard enough to taste metal.
He didn't have time to breathe.
Sephiroth was already walking toward the access gate again, coat trailing, blade low at his side, as if the near-fall had been nothing more than a minor inconvenience he'd corrected.
Zack shoved himself upright, lungs burning. His hands shook—not from fear, he told himself, not from fear, just from heat and effort and the way the chamber seemed to vibrate through his bones like it wanted him to fall.
"Sephiroth!" Zack shouted, raw now. "This isn't freedom. This is you being pulled."
Sephiroth paused.
Just long enough for Zack to hope.
Then Sephiroth turned his head slightly, and the look he gave Zack wasn't hatred.
It was pity.
The kind you give a person still clinging to a story you've already outgrown.
"You're still trying to save me," Sephiroth said, voice almost soft under the roar. "Even now."
Zack lifted the Buster Sword again, forcing the blade up through trembling arms. The steel felt heavier than it had any right to, like it had absorbed every promise ever made with it and was now demanding Zack pay for them all at once.
"I'm not letting you do this," Zack said, and the words came out more like a vow than a threat.
Sephiroth's mouth curved faintly, not mocking—worse. Appreciative.
Then the Masamune rose again, and the chamber tightened around them, heat shimmering, mako roaring below like a living audience.
Zack took one step forward on slick metal.
Sephiroth took one step forward like the floor belonged to him.
And the green river beneath them surged—bright and violent—like it had decided this fight mattered enough to answer back.