Disclaimer: This fanwork is written with respect to the original FF7 canon and in accordance with the permissions of Fair Use as a transformative work. No profit is being made.
A/N: The Ao3 posting of this fic has links to the relevant background headcanons I've written on my Tumblr. It's not necessary to read them in order to understand this.
Zack wasn't sure where on the human-to-monster scale he fit these days - did it count when you were dead? he was pretty sure it shouldn't count - but he was positive he wasn't an Ancient. The only reason he was still able to keep a presence in the Lifestream was because Aerith was. Then again, she'd said more than once that his willpower was pretty impressive too. Apparently that was what let him leave her side at all.
Which was exactly what he was doing while she was helping Cloud deal with Geostigma and the three boys Sephiroth had crafted in his image. Cloud was his friend, but he had more than Zack. Right now, someone else needed him.
The former SOLDIER didn't acknowledge him, a much more solid presence in the Lifestream just by sheer power, washed out gray-green eyes watching the living with obsessive attention. Cloud was easy to see, and Zack winced at the flashes of the silver haired boys that Sephiroth had thrown out into the world.
Zack stopped close by, on almost stable footing in the bubble of power the older man held around him. "Sephiroth, listen to me. You can't keep doing this. Let it go, man, we're dead."
"You're dead," Sephiroth corrected absently. "Fragile human that you are."
"Oh god, can you not do this now?" Zack grit his teeth, trying to find any sign of the man he'd once called friend. "Sephiroth, you have to stop this."
"It will end soon enough." A small smile curved his lips, watching the littlest one baiting Cloud. "Good puppets, aren't they? A pity your friend didn't want to play along… no matter."
"Don't do this." Zack wasn't afraid to beg, he was afraid it wasn't working. "Let it go. Please, just let it go, Sephiroth. Our time's up, there's nothing out there for us now."
"I don't expect you to understand." Sephiroth's tone was suddenly softer, more familiar, and he turned his head to offer that same little smile. "You never really understood, but that's alright. You're only human, after all."
"So are you," Zack insisted.
Sephiroth chuckled softly, looking back at Kadaj and Cloud's battle. "I am beyond humanity. And my time is only beginning."
"Sephiroth -" Too late, Zack saw Kadaj falling, curling in on himself and taking in the remaining concentration of Jenova cells. He spent a breathless moment cursing ShinRa as Sephiroth vanished from his side, taking over the body of his little remnant. The smile he gave Cloud as their swords clashed was chilling.
"Zack?" Aerith came to his side, bringing the illusion of flowers in her wake and filling the cold space Sephiroth had left behind. She touched his arm lightly, green eyes full of concern. "It's up to Cloud now."
"It should never have been his fight." Zack crossed his arms, tracking the fight with his eyes and feeling a terrible certainty settle like ice in his gut. "He's not going to make it."
"His Geostigma is gone, and he has the strength," Aerith said. "Cloud has what it takes, and his friends are there just in case."
"Sephiroth was fighting in a war when Cloud was still a kid, Aerith, the man could have beat him on muscle memory, that's not even talking about sheer power." Zack ran a hand back through his hair. "He's toying with him, and Cloud doesn't have enough faith in himself to take advantage of it and end the fight."
Aerith sighed quietly. "What are you going to do about it?"
That was the question, wasn't it?
"Tell me what you cherish most."
Zack arched a brow slowly, a grim smile on his lips. "I have an idea."
"Be careful!" Aerith watched him go, clasping her hands loosely. Be safe, Zack. I don't want to lose you again.
Zack hefted the Buster Sword, grimacing at the rust and wear on the blade. It would do its job, though; the Buster was far too well made to be ruined so easily. And maybe it was a little fitting, bringing it with him in that state to have Cloud's back. It was taking a lot of energy to pull it off, but if he could just end this, if he could just make sure it never happened again, that this nightmare that had been going on since he was a teenager would finally end… maybe things would finally be alright.
He could see the look on Cloud's face coming in, all the pain and loss and that same self doubt that had haunted him for as long as Zack had known him. It wasn't an expression he could look at long, standing at Cloud's back to get his composure together. "Hey. You need a hand?"
The blond shook his head, using his sword as a crutch to get upright. "Zack…"
God, that voice. He sounded so lost, like Zack was somebody who could make a difference. Who had made a difference, instead of a load of very painful and costly mistakes. Blinking back tears, he tried to keep up a positive tone; if that lie helped Cloud, right now wasn't the time to argue it. "You already beat him once, right? Should be a cinch. Just… remember what I told you."
"That is ironic."
Zack froze, breath catching at a voice he honestly hadn't expected to ever hear again. "Angeal?"
His mentor shimmered into view a few paces away, eyeing the Buster Sword ruefully. "I think it's time I take that burden back."
"But…" Zack could hear Cloud murmur his name in confusion, but he could only stare as Angeal held a hand out, the Buster appearing there like it had been called. "Angeal, wait!"
"This shouldn't have been your fight." Angeal offered a small, sad smile. "I'm sorry. This time, we'll set things right."
The Lifestream construct broke around them, Zack left behind in limbo as Angeal took a fighting stance in front of Cloud. "That's enough, Sephiroth."
For a moment, Sephiroth stared blankly at him, eyes trailing along the two white wings as Angeal took to the air. "I knew you, once."
Angeal nodded slowly. "There's a lot you've forgotten, my friend."
"I have no friends, nor do I need them." His expression closed off once more as he flicked his blade in challenge. "Stand aside, or your fate will go with the rest of the traitors."
"I can't do that." Angeal readied himself, broad shoulders set. "This has to end, Sephiroth."
"And so I shall end it." Sephiroth launched himself down, gravity lending him speed and force behind his blow, driving Angeal back. "Is this the best you can do? You should have let Cloud try before he bled out. At least he stood a chance. You are nothing-"
A streak of fire roared across the building, cutting off Sephiroth's advance. "I don't remember you being this chatty."
Boots clicked quietly along the ruined metal, a long crimson blade deflecting a streak of blue energy thrown by the force of Sephiroth's blade as the redhead joined Angeal's side. "And so the three friends are reunited once again."
Sephiroth looked between the pair a moment, frowning. "… you should not be here…"
"He doesn't remember," Angeal explained.
"Well." Genesis chuckled softly, a gloved hand running down his blade until its runes gleamed. "I guess I'll have to beat it into his head, then."