The Last Apprentice Series - Books 1-8 by Joseph Delaney - Revenge of the Witch, Curse of the Bane, Night of the Soul Stealer, Attack of the Fiend, Wrath of the Bloodeye, Clash of the Demons, Rise of the Huntress & Rage of the Fallen

The Last Apprentice Series or Wardstone Chronicles center on Thomas Ward, the seventh son of a seventh son who is apprenticed to John Gregory to become a Spook - a master fighter of supernatural evil. John Gregory, the Spook for "the County" is gives Tom practical instruction on tackling ghosts, ghasts, witches, boggarts, and all manner of other things that serve "The Dark". Tom soon discovers that most of John Gregory's apprentices have failed for various reasons, including being killed in the process of learning how to be a Spook. As the Chronicles progress the focus expands to other characters such as the assassin Grimalkin and the young witch Alice Deane. Overall, the series revolves around Tom's destiny to either save the world or destroy it. The movie "Seventh Son" was based on this series.