From Lexicanum

The Ishandruir is an ancient Eldar text that exists on a tablet that was written thousands of years ago by the Farseer Lsathranil of Craftworld Ulthwé which spoke of a prophecy relating to the Necrons that were trapped in stasis on the planet Rahe's Paradise.

According to pages 1-2 of 3 of the text:

The banshee's call shall wake the dead when dark portents was nigh,

Heed them as the counsel of a seer, or a father.

The Yngir, who have sleep since the very birth of Chaos,

Shall crawl once more frmo their tombs, thirsting for warmth.

The war of heaven shall be as nothing to their vengeance,

For the sons of Asuryan, few in number, cannot stand against them.

And the Eye of Isha shall dim, closing for all eternity;

Such a gentle goddess cannot witness the atrocities they will wreak.

The soulless ones shall be the harbingers of the dark fate,

And then shall come the living dead, the progeny,

The thirsting ones, the forever damned,

And the galaxy shall run red as the blood of Eldanesh.¹

Source

• ¹:Dawn of War Omnibus Ascension by C. S. Goto (pg 455)