Zack's arms were starting to understand fatigue in a way his pride refused to acknowledge. Every block rattled up through the Buster Sword and into his bones like the refinery was trying to play him as an instrument, and the heat below kept rising in ugly waves that made the far scaffolding look soft—like the whole world was melting out of principle.
He'd gotten a hit in. One. A shallow cut, a thin red line on Sephiroth's cheek—proof that flesh still existed under the myth. Proof that this wasn't a dream you woke up from laughing.
Sephiroth touched the blood with two fingers like it was a new concept, like he was tasting a fact. Then he looked at Zack again—not angry, not shaken. Curious.
Zack's stomach turned.
It wasn't the blood that scared him. It was the way Sephiroth didn't care about it. Like pain was just another data point. Like the only thing that mattered was what direction the story was moving.
"Seph," Zack breathed, and his voice came out wrong—too thin for a room this loud. "Please."
The refinery answered for him with that grinding hymn, turbines chewing the planet's voice into something Shinra could invoice. The mako below surged brighter for half a heartbeat, and Zack hated himself for the thought that it looked… responsive. Like a crowd leaning forward.
Sephiroth stepped in again.
Not a lunge. Not a charge. A decision.
The Masamune slid through the air with that clean, singing note, and Zack caught it with brute steel and stubbornness. Sparks snapped—orange against green—brief little stars born out of betrayal. Zack's boots skidded on metal slick with condensation and sweat, and he had this stupid, vivid realization that the floor was doing the same thing Sephiroth was doing: pretending to be stable while quietly trying to throw him into the light.
Zack shoved back. He didn't win ground. He borrowed seconds.
He tried to speak through the impacts—tried to force human words into a fight that was becoming something else.
"You don't—" clang "—have to—" clang "—do this—"
Sephiroth's eyes didn't even flicker. They stayed calm in a way that made Zack want to shake him, because calm belonged to people who hadn't just had their whole identity turned into a lab report. Calm belonged to people who were still choosing.
Zack swung wide, heavy, honest. Sephiroth slipped inside it like he knew Zack's body better than Zack did. The Masamune kissed the Buster Sword's edge and slid, searching for a seam, for a tendon, for a clean end.
Zack jerked back on instinct, shoulders screaming. He caught a glimpse of Sephiroth's cheek again—blood still there, thin and bright—and something in him snapped that had been holding since the first day he'd looked up at Sephiroth and decided that's what I want to be.
Not the power.
The purpose.
The certainty.
Zack's throat tightened until the next words felt like tearing cloth.
"I would've followed you anywhere," he said, and it came out raw—anger and grief packed into one line. "I trusted you like family."
For half a second, something almost warm crossed Sephiroth's face.
Not remorse.
Not doubt.
Recognition, the way you recognized a song you used to like before it got twisted into propaganda.
"That's why you have to die first," Sephiroth said, almost gently.
The words didn't hit Zack like an insult.
They hit him like a verdict stamped in red ink.
Zack's breath caught. His eyes stung—not from smoke, not from heat, but from the stupid, animal part of him that still wanted to believe friendship could outmuscle fate.
"You don't mean that," Zack said automatically, because denial was a reflex and he'd always been good at reflexes.
Sephiroth didn't answer.
He moved.
Zack barely got the Buster Sword up in time. The impact rang through his arms so hard his fingers went numb. He staggered back, heel catching a seam in the catwalk, and for a sick flash he felt gravity tug like a hand at his spine, eager.
He forced his footing. Forced air into his lungs. Forced himself to stop thinking about the mako below as anything except death.
Sephiroth kept advancing, not hurried, not frantic. It was worse than rage. Rage was messy. Rage made mistakes.
This was controlled.
This was clean.
Zack gave ground because he had to. Each step backward was a compromise he hated. The catwalk narrowed, the railings thinning into something more symbolic than functional. Heat rolled up from below in shimmering sheets, distorting Sephiroth's silhouette until he looked half-real, like a statue seen through water.
Somewhere deep in the refinery, alarms started to bleat—distant and useless, the building's way of pretending it had morals.
Zack's boots hit a junction where the path split upward, a laddered access route leading to a higher platform. Above, a narrow gantry stretched out over the core like a bridge designed by someone who'd never once considered mercy.
Zack glanced down and instantly regretted it.
The mako wasn't just "below" anymore. It was there—open channels of exposed Lifestream roaring through the refinery's heart, blinding green-white light surging like molten poison. The air above it rippled with heat distortion so thick it made the world look unreal, like reality was having trouble agreeing with itself.
Mustafar, if Mustafar wore Shinra steel and corporate signage.
Zack's mouth went dry. His skin prickled under his uniform like the planet was trying to crawl out through him.
He backed onto the ladder route without taking his eyes off Sephiroth. Hands tight on the Buster Sword. Breath shallow. Every instinct screaming don't climb higher—but the lower paths were collapsing behind them, buckled catwalks and snapped supports turning the refinery into a maze of half-falling bridges.
Sephiroth followed, perfectly balanced, coat trailing behind him like a flag that had chosen its country.
They climbed into the upper level and the sound changed.
Down below had been roar—mako and turbines and grinding machinery.
Up here it sharpened into something more intimate, like the planet's voice had gotten close enough to speak directly into your skull. The hum threaded through the metal under their feet and up into Zack's teeth, vibrating in a way that made him want to clench his jaw until it broke.
The gantry stretched ahead: narrow, exposed, with the core yawning beneath it like a mouth.
Point-of-no-return geometry.
Zack stepped onto it and felt the immediate, terrible clarity of the place. There was nowhere to run that didn't end in light. No side path. No cover. No civilians to save, no troopers to shout at, no chain of command to blame.
Just him.
Just Sephiroth.
Just the space between them, filled with heat and history and the sick certainty that the world was rearranging itself around this moment.
Zack planted his feet.
Not because he felt brave.
Because he couldn't keep backing up forever.
Because if he took one more step, he'd be admitting—physically, unmistakably—that Sephiroth was right: that Zack was just an obstacle to be removed on the way to something "real."
His chest heaved. Sweat ran cold down his spine despite the heat. His arms shook, just a little, and he hated that too.
Sephiroth stopped a few paces away.
The cut on his cheek had dried into a dark streak. In the mako light it looked like a mark you wore on purpose.
He stood there, calm as scripture, and the refinery's glow painted him in sickly holiness—angel-green and winter-white and something older behind the eyes.
Zack lifted the Buster Sword higher, the blade catching the light in dull flashes.
"You hear me?" Zack said, voice rough. "You're not walking past me."
Sephiroth's gaze slid over him, not dismissive—measuring. Like Zack was a door. Like Sephiroth had already decided how to open it.
Down below, the mako surged again, and the light flared so bright Zack saw afterimages when he blinked.
The gantry trembled under their combined weight, metal groaning like it knew it was about to be asked to hold something it wasn't built for.
Zack held his ground anyway.
Because someone had to.
Because brotherhood wasn't just the warm parts. It was this too: the narrow place, the ugly choice, the moment you stopped the person you loved from becoming something that would eat the world.
And across from him, Sephiroth shifted his grip on the Masamune—ritual calm, surgeon's hands—and Zack felt the air tighten like the refinery itself was holding its breath, waiting to see which of them the planet would recognize when the next strike fell.