The Ashen Hourglass by Mark E. Cooper

Captain Adrian Rourke died destroying a dungeon on the slopes of Mount Diablo after forty years of war.

Then he opened his eyes in his eighteen-year-old body, decades before his death and roughly three months before the world would begin to change.

His family was alive. Civilization was still intact. The supernatural apocalypse known as the Revival had not yet officially begun.

But Adrian hadn't returned empty-handed.