The Spook's Blood by Joseph Delaney

Time is running out for Thomas Ward. His final battle against the Fiend is drawing near, and the Spook's apprentice has never felt more alone in his task.

Isolated and afraid, the Fiend is set to send the greatest of his servants against him - Siscoi, a Vampire God more ferocious than anything he has yet faced. Tom must risk his life to prevent the evil beast from entering this world, even as he learns that the final destruction of the Fiend may involve a sacrifice more terrible than he can imagine...

I borrowed the summary from Joseph Delaney's website. Tom and the Spook have been sent to a library by one of the Spook's former apprentices. The Spook wants to buy new books so he can fill his rebuilt library with them. Something isn't right with the house and its inhabitants though. This time the Spook can't help Tom. He has to find a way to battle the vampires alone. With the help of Alice and Grimalkin Tom has to fight for his life again.

This book has such a beautiful cover, I can't stop looking at it. The vampires were another evil Tom had to fight. I liked that angle in this series. Tom has to beat many monsters and great evil, so it fits. Of course there had to be something very gruesome and mean for Tom to go up against again. Tom's growing up, that's so good to witness. In every book he becomes a little bit wiser and he learns from his mistakes. Sometimes he needs a little bit of luck and that makes him more likable. I'm still loving this series!