Coven Ascending, Season One (An Ash Falls Series) - J D Mankowski - Bog

Eva, a formidable young witch, has one job; clean up whatever remains of the Coven's latest victim. Unfortunately for her, that's easier said than done when the victim's roommate returns home from vacation. Magic is supposed to simplify life, but all it seems to do for Eva now is create more chaos. She's not ready to kill an innocent stranger, but she may have to if she wants to continue being a witch.