This is in essence one of the prophecies of Mandos regarding the Dagor Dagorlad as written in HoMe. It is, however, not finished yet, as the aftermath is yet to be described (Simlarils recoverd, trees revived, Arda rebuild, Túrin becomes a god.)
The Prophecy of the Final Battle
Now hark ye men and elves of old
To words that long ago were told:
In brightest land on brightest day
The Doomsman on the world did lay.
When years uncounted pass away
Across the distant ocean grey
And years lie thicker than the leaves
Beneath the fading forest eaves,
When green has long since passed to brown
And rowan bears no more her crown,
When Earth is old and dotard sun
The fading light of moon doth shun,
When ocean humbled breaks no more
Upon the tame and crumbled shore,
When weary gods no longer feast
And watchfulness has long since ceased,
When all of heaven’s stars are paled
And Time on Vigour has prevailed,
When all the world is one great grave,
Then back shall come the dreadful knave.
The Sun and Moon shall be destroyed
Upon his coming from the Void,
But Evenstar will cast him down
As bright white flame with brighter crown.
The weary gods he’ll overwhelm,
And ravaged be the Blessed Realm
When on the field the battle starts
`Tween light and dark, and many hearts
Be broken in Undying Lands
While red are washed its dying strands,
And in the midst of chaos great
Decided is the world her fate
Where three most great of all the earth
Against most mighty prove their worth,
Against the greatest of all kings:
The deity dark who darkness brings.
The God of Strength shall fight the Foe
And wrestle him without a blow,
While on his right the Herald stands
With shining weapons in his hands,
Whose skill at arms most great of all
Does battle with Constrainer tall.
But all their valour good for naught
Had on their left not bravely fought
The man who once had mastered doom
But doom had mastered to his tomb,
The one whom Dark most dreadf’lly cursed
Will forth from Doomsman’s halls have burst.
And there the Conqueror of Fate
Will slay that what he doth most hate.
And t’will be Túrin’s black sword’s steel
Its death and final end will deal:
Avenged are thus the Second Born
And Húrin’s children rid from scorn.