The fourth book in the epic Egyptian series

The fourth book in the epic Egyptian series 'She is omnivorous. No matter age or appearance, physical frailty or imperfection. It is not their flesh that feeds her appetites, but their souls. she devours the young and old, men and women. She leaves only a desiccated husk.' An unspeakable evil. An impossible gift. Renowned magus Taita is now over a hundred years old, and has ascended to a new level of wisdom and understanding about his world. But he must prepare himself for the greatest threat Egypt has ever faced: the great plagues and the fair of the Nile, brought about by the fire witch Eos, an ancient force of sheer evil. Taita must risk his soul to battle against Eos, or his homeland and everything he has ever loved will be lost forever. But there are other reasons for Taita to fight -- since success could also mean rewards he could never have thought possible...