When the Heavens Fall (The Chronicles of the Exile No. 1)

A power-hungry necromancer has stolen The Book of Lost Souls, and intends to use it to resurrect an ancient race and challenge Shroud for dominion of the underworld. Shroud counters by sending his most formidable servants to seize the artefact at all cost. However, the god is not the only one interested in the Book, and a host of other forces converge, drawn by the powerful magic that has been unleashed.