From the books Amazon page:
The Thirteen tribes of Cain are a cursed people. Descending from Lilith
and Cain’s unholy union, they have lived in the shadows since the
creation of the world. Finally, after a millennia of waiting, Armageddon
is nigh. Soon they will have their chance to end the reign of the
children of God and rule the Earth. Yet, these creatures of myth are
losing their patience. War threatens to destroy them all. Will there be
any of them left when the Master calls them to arms? Will they win the
final battle? Will evil finally prevail over good?