Lord Loss by Darren Shan (The Demonata #1)

The first book in the Demonata, the demonic symphony in ten parts by multi-million-copy bestselling horror writer Darren Shan…
When Grubbs Grady first encounters Lord Loss and his evil minions, he learns three things:
• the world is vicious,
• magic is possible,
• demons are real.
He thinks that he will never again witness such a terrible night of death and darkness.
…He is wrong.