Series: Obsidian and Blood #2
The Revered Speaker has died and the council must agree on his successor before the Fifth World succumbs to the star demons (this is a fantasy set in the Aztec Empire in the late 15th century). Acatl (the high priest for the dead) investigates when a star demon appears to have been summoned within the palace to murder someone. They believe the stars are demons that can fall from the sky and rip a man apart (sun worshippers, remember). Basically, Acatl becomes afraid that if the council takes too long to choose a new Revered Speaker, they won't have sufficient protection and the stars will fall from the sky and bring about the end of the world. The end of their world, anyhow.
Unfortunately, the middle part of the book with the investigation seemed to go on too long and it feels like I took forever to read it. It was a lot slower (reading time wise) than the first book, anyway. I'll still go on to read the third one but I really hope it picks up.
I read this for the "Monsters" square for the Halloween Bingo. It qualifies due to the star demons and the ahuizotls (water creatures). There may have been other creatures mentioned but I don't remember them specifically. This book would also work for the "Murder Most Foul", "Supernatural", "Demons", and "Terrifying Women" squares.