Necropolis

"After blasting open the gates of the underworld, the Cerberus warriors face a fresh evil. Deep beneath the African continent, a hidden city teems with bloodthirsty creatures ruled by a vicious queen. As her shape-shifting minions swarm to outmaneuver Kane and his allies, the rebels race to contain the unfurling horror. With the undead descending upon Africa, the warriors must escape a destiny far worse than they could ever imagine—as tortured ambassadors for the vampire kingdom." — from this book's back cover