The Embers of Penthesil

When missionary David treats a mysterious woman who walked out of the jungle, he witnesses the impossible: she absorbs fire into her very being. He is soon dragged into a terrifying chase, hunted by inhuman "Valkyries" serving a cosmic Empress. Trapped on a boat with the fugitive Cassara, whose body is a vessel for a terrifying, world-ending power, David's faith is shattered. He must unravel the secrets of her past before her pursuers—or the monster she holds within—consumes them both.