Disclaimer: I own nothing referring to Final Fantasy or other corporation's works.

"Ascension"

(What truly happens when Sephiroth dies)

'Amiss this cloudy plain,
I realize how my plan was vain.
To relive my mistake, Strife; our paths shall ever cross,
No matter the stake, it shall always have been my loss.'

'Now as I stand, judgment and accusations before me,
My atonement shall cure their blindness, and all shall see.
The power from deep within, no longer desecrated,
My ascension and I exalted high, my new being created.'

'Bountiful land of dead souls, the limitless magic,
The powerful Judgment Gate, its symbols angelic.
For the last and final time, Strife, shall our paths entangle,
I'm the One Eternal, long live the One Winged Angel.'

'Upon thy throne on which I sit, I rule creation,
No longer my body a cursed damnation.
Sane again, those Cells now gone,
I rise again, to greet thy dawn.'

'To heal the Planet, to end its cries,
To cleanse its spirit, n'er more the blood red skies.
It'll go away at my command,
For the universe sits upon my hand.'

'My grand ascension, you shall fear,
My return before you, intentions clear.
Amongst this lonely plain, none hear the cries.
I'll rule uncontested, the Zero World skies.'

"Ascension"