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. His gloves were slick—condensation, sweat, maybe both—and the metal beneath his boots kept pretending it was a floor while quietly auditioning for "trapdoor."
Sephiroth didn't look tired.
That was the part that made Zack want to throw up.
Not because Sephiroth was "strong." Zack could live with strong. Strength was just physics with a better haircut. This was something else: an unnerving efficiency, a calm that didn't fray no matter how the heat distorted the air or how the mako roared below like a living audience.
Zack shifted his stance, forcing his feet to stop skidding, forcing his breathing to stop sprinting. He tried to keep his voice steady, like steady could still be magic.
"Seph," he said, and the name came out as a rawer thing than he meant it to. "We can still—"
Steel met steel again. Not a flourish. Not a "fight." A correction. Sephiroth's Masamune kissed the Buster Sword with that thin singing note that threaded into the refinery's throat-sound, and for a second Zack couldn't tell where metal ended and the planet's forced hymn began.
Zack shoved back, teeth clenched, trying to make it messy. Trying to make it human. He swung wide—heavy, honest, desperate—and Sephiroth slid away from it like the air itself was giving him permission.
Then Sephiroth paused.
Not like a man hesitating.
Like a man listening.
His blade stopped mid-motion, hovering at an angle that made no sense for defense. His head tilted a fraction, as if the roar under the catwalk had formed a syllable worth hearing.
The chamber tightened around that pause. Zack felt it in his ribs. The mako's light sharpened into something almost white at the edges, and the heat shimmer thickened until the far scaffolding looked like it was melting out of existence.
Sephiroth's eyes didn't go distant.
They went clear.
The calm didn't break into rage. It refined into something predatory—something that belonged in deep water, not on land. Zack had seen killers before. He'd even been one, on paper. This wasn't that.
This was possession-adjacent clarity. Like someone had leaned over Sephiroth's shoulder and whispered the exact shape of the next ten seconds.
And in the gaps between the refinery's grind—where your brain normally found silence—something slid in.
End him.
It didn't arrive as sound. It arrived as instruction.
Zack's stomach dropped because he knew, with a cold kind of certainty, that Sephiroth had heard it more cleanly than he had.
He is the chain.
Sephiroth's speed changed.
Not adrenaline. Not anger. A switch flipping into a setting Shinra hadn't installed.
He moved, and Zack barely had time to lift the Buster Sword before the Masamune was already there—too fast, too precise, cutting the air like it was the thing that had done wrong.
Zack blocked on instinct. The impact punched numbness into his wrists. Sparks snapped—orange, brief, furious—against the chamber's green glare.
He stumbled a half-step, boots skidding on wet metal. The roar below surged, brightening for a heartbeat like it liked the taste of the moment.
"Okay," Zack breathed, and the word wasn't a joke, wasn't even really speech. It was his body trying to keep itself from panicking. "Okay. Cool. Love this new vibe. Super normal."
Sephiroth didn't answer.
He came again—high, then low, then a cut that looked like it was meant for Zack's throat but landed on the Buster Sword's edge with a sound that made Zack's teeth sing.
Zack shoved forward anyway.
Because if he let Sephiroth dictate distance, he'd lose. Not "lose the duel." Lose the person. Lose the last thread of maybe.
He feinted left—an ugly, deliberate lie—then drove his shoulder in hard, close enough to feel heat rolling off Sephiroth's coat like it was carrying its own weather.
Sephiroth's guard caught the Buster Sword, but Zack didn't aim for clean. Zack aimed for contact. For impact. For something that would force a crack in that surgical rhythm.
The Buster Sword slammed into Masamune's angle with a brutal, grinding collision. Metal screamed. Sparks burst outward in a bright spray that looked like a tiny fireworks show trying to be brave in hell.
Zack used the opening like it was oxygen.
He stepped through the lock, twisted his hips, and shoved—hard—turning the whole movement into a shove-you-off-the-ledge kind of strike. It wasn't elegant. It was Zack. It was stubbornness in physical form.
Sephiroth's blade shifted—fast, but not fast enough.
For the first time since the core chamber swallowed them, Zack landed something real.
The Buster Sword's edge kissed Sephiroth's cheek in a shallow line. Not a killing blow. Not even close. Just enough to prove skin still existed under the myth.
A thin cut opened—clean, almost polite—and blood welled bright against pale flesh.
Zack froze for half a heartbeat, shocked by the fact that it worked.
Sephiroth froze too.
And in that tiny stillness, with mako roaring beneath their feet and heat trembling in the air like a fever, Zack saw it: the moment Sephiroth registered the sensation not as pain, not as insult, but as… information.
Sephiroth lifted two fingers to his cheek.
Slowly. Curiously.
He touched the blood and pulled his fingers away, watching the red catch the green light like it didn't belong in this room.
Like it didn't belong in him.
His expression didn't twist into anger. It softened into fascination.
A faint curve touched his mouth—not a smile, not really. More like the shape of a new thought being born.
Zack's grip tightened until his knuckles ached.
"Seph," he said again, voice cracking despite his best effort, because grief has a way of slipping past training. "Please. That—that was me. That was your friend. You still—"
Sephiroth's eyes lifted to meet his.
Green-lit. Calm. Owned.
The blood on his fingers gleamed, and the refinery's hum seemed to lean in closer, intimate as breath against skin.
Sephiroth lowered his hand, still staring at Zack like Zack had just proven something important.
Then he moved his blade again—light, deliberate—like the cut on his cheek had been a blessing, not a warning.
Like the chain had just tugged, and the thing holding it had decided to pull back harder.