The Devourer's Sonata - Rebecca St. Claire

Danika Sarkovski was born an outcast and an heiress, a Gloamblood monster hunter who walked away from her aristocratic bloodline. When her estranged father, Professor Cassian Struchmeyer, vanishes chasing a legendary musical tome, the Lamentata Nihilith, Danika is tasked with finding both the man who abandoned her family and the artifact whose song may unmake kingdoms.

She journeys with Elira Dimitriou, a sharp-tongued librarian and devoted student of Professor Struchmeyer whose magic eats her memories one spell at a time. In drowned ports and unhallowed markets, amid brain-sucking cephalopodian pirates and revenants guarding ancient tombs and temples, Danika must decide what she is willing to feed-her hunger, her grief, or the fragile trust growing between Elira and herself.

Because somewhere beyond the floating cities, snow-covered wastes, and crystal deserts, a man with a harp made of humanoid bones tunes the Devourer's Sonata-and if he finishes the song, all creation will be fed to the Eternal Maw.