Demon Thief (The Demonata, Book 2) by Darren Shan
After the horrors of Lord Loss, the terrifying "Demonata" series continues with the "Demon Thief". "A huge, jagged patch of light forms at the foot of my bed. Then a shape presses through. I'm too horrified to scream. It's a monster from my very worst nightmare. Pale red skin. Dark red eyes. No nose. Sharp, grey teeth. As it leans further forward I see a hole in the left side of its chest, and inside - dozens of tiny, hissing snakes. The monster frowns and stretches a hand towards me!" When Kernel Fleck's brother is stolen by demons, he must enter their universe in search of him. It is a place of magic, chaos and incredible danger. Kernel has three aims: learn to use magic, find his brother, and stay alive. But a heartless demon awaits him, and death has been foretold!