Battle of the Silent Fields

In XI, 170, on the night of Twilight's Tide, Daemons streamed from the upper slopes of the Annulii Mountains. The horde ravaged much of eastern Saphery before an army led by the Everqueen blocked its path. So began the Battle of the Silent Fields -- site of the largest concentration of waystones beyond the Isle of the Dead.

The Daemons were rapacious, eager to bring their madness to the mortal world. Yet the Elves, heartened by the Everqueen's presence and shielded by her sorceries, met their fury with resolve. Flesh Hounds hurled themselves forwards, only to perish on Elven spears. Furies swooped from the skies to tear at the crews of Eagle Claw bolt throwers, but were driven back by valiant Ellyrian Reavers. Daemonettes were felled by the arrows of Shadow Warriors, the volleys loosed quicker than the eye could follow.

As time wore on, and midnight approached, the Everqueen felt her magics ebb -- Twilight's Tide had ever been a night of Chaos ascendant, and as the dark powers rose, hers diminished. Yet as the tainted moon loomed high over the battlefield, mist fell over the plain, and the waystones burned with white flame. For a moment, silence reigned.

In that moment, a change fell over the High Elf army. Wounded warriors felt hands at their side, helping them to their feet. Regiments that had suffered terrible losses found their ranks filled once more. A few Elves fancied they caught glimpses of comrades long lost, or heraldry long passed out of services. But such thoughts were as elusive as dreams in the noonday sun, and were lost as soon as they were formed.

Whatever occurred that night, it brought fresh determination to the High Elves. Down into the mists they went, weapons ready, and hearts set to a final victory -- and a great victory there was. As spear and sword struck home, they blazed with the same white fire that played about the waystones. By the times the cursed moon had passed from the sky, and the white fire had faded from the waystones, the Daemon host had been utterly destroyed. Of their unlooked-for allies, the Elves found no sign. Even as they searched, the memories of that night faded with the mist, leaving only a sadness that none could fully explain.

Source
pg. 29
 * Warhammer Armies: High Elves (8th Edition)