At first glance, this is a well researched series about an order of medieval assassin nuns sired by Death Himself, so I was pretty much already sold. But THEN I started reading it, and could not stop. For weeks. I burned through all 3 books (and the related upcoming February 2019 release Courting Darkness) in like a week and a half.
The series takes place in 15th century Brittany, a time when everyone is at war, the duchy has been inherited by a 12 year old girl, and the Catholic Church chose to actively subsume pagan beliefs in order to gain acceptance among a reluctant populace. It is one of these old pagan gods, Mortain, now considered the patron saint of death, that our heroines worship and struggle and fight for. But they are also fighting for themselves.
The history is fascinating, the trauma is brutal but very well handled, the romance is the healthy and supportive (but fuuun) kind that you want your teens reading about, and the weapons are historically accurate. Don't you want to read about young women finding self actualization and liberation through violence and subterfuge and epic battles? DON'T YOU?