Gideon the ninth
(Book)

Series information from Goodreads.com.

Gideon has a sword, some dirty magazines, and no more time for undead bullshit. Brought up by unfriendly, ossifying nuns, ancient retainers, and countless skeletons, she is ready to abandon a life of servitude and an afterlife as a reanimated corpse. Harrowhark Nonagesimus, Reverend Daughter of the Ninth House and bone witch extraordinaire, has been summoned to a deadly trial of wits and skill. If Harrowhark succeeds she will become an immortal, all-powerful servant of the Resurrection. Without Gideon's sword, Harrow will fail, and the Ninth House will die. Of course, some things are better left dead. -- adapted from jacket