Demon Apocalypse

A boy watches his world collapse in front of him. A vengeful demon lord is determined to make someone pay, and he commands a horde of monstrous Demonata that spills across the land. Civilization is unravelling, and the familiar world is on the brink of ending.

This is the sixth book in Darren Shan's Demonata series. Shan is also known for the Cirque Du Freak books, which have sold widely in the United States. Demon Apocalypse is a horror story for younger readers that leans into gore and dread, and it is meant to unsettle readers well after they finish it.