It was quiet, down here in the once-beautiful mansion. The sunlight falling through the great stained-glass windows was tired and wan, softening the edges of the man sitting on an old crate. His long silver hair was dusty from having lain immobile for so long, his armor a dead gray. The black leather, once gleaming, was faded now, so like the other man he'd once fought alongside. Translucent skin tore at the slightest breath, veins blackened and died slowly across his face and bared chest, the once bright green eyes now blind. His hand was outstretched, at first willingly, then forcibly...now, he didn't care. The wraith that clung to it, sucking his life's blood from the two small punctures in his wrist, was clad appropriately in black and red. Shaggy, tangled black hair hung low over hell-red eyes, set in a handsome face only a little paler than his...or so he recalled. The numbness that had started at his hand was nearly finished spreading now, reaching his left foot with haste. The spectre he'd found paused in his feeding, and Sephiroth felt two long fangs withdraw from his skin, that presence of power as yet unrivaled moving away from him. As he succumbed to the darkness, he heard the other speak, a quiet, haughty baritone.
"Good bye, my son. Thank you for returning to your father that which is rightfully mine." Vincent straightened the sunglasses that had appeared when his form changed, and glancing back over at the corpse, gave it a soldier's salute.
It's a strange little piece, but for some reason, I can envision it far better than my words can describe.