The maleficent seven by Derek Landy

Skulduggery Pleasant series. HarperCollins Children's, 2013. ISBN 9780007512386. 284 p. paperback
(Ages: 12-14) Themes: Good and evil. Skeletons. Magic. Fantasy. Sorcery.
Irish author Derek Landy's novella departs from the usual protagonists Skulduggery and Valkyrie, focussing on Tanith Low's dark corrupt character who now is permanently possessed by a Remnant spirit. Tanith recruits a team of villainous characters to search for and steal the four God-Killer level weapons to help Darquesse in the destruction of the world. The first weapon the team needs to find is the dagger at the German Sanctuary. Her crew are pitted against a secret group of Sanctuary sorcerers lead by Dexter Vex. Billy Ray Sanguine, one of her team, is particularly blood-thirsty, using his cut-throat razor to protect Tanith.
Tanith's back story is interspersed with the action chapters. She is left by her parents to work with the master Quoneel and other masters, learning the art of sorcery, killing, forgery and wall-walking. At this stage she still has a conscience.
The battles are graphically described; the killings matter of fact and the characters assisting Tanith are truly evil. This is another very dark story that will be welcomed by fans of the Skullduggery Pleasant series. Background understanding of this fantasy world is needed to read this book.
Rhyllis Bignell