Silver Threads, book one: The Last Ending.

Since time immemorial, angels have ruled the world. Humans, animari and even demons . . . all but shiver at the sight of those winged creatures ancient and without conscience - ancients and without conscience.
Now, violent and eerie events around the world threaten to wipe out entire civilizations: the sky roar, seas boil, the earth shake. Among the surge of devastation stands Yavannah.
A demon, a traitor . . . nothing the world would miss - and yet, something is chasing him and won't stop until his nightmares come to life again.