Courting Darkness by Robin Lafevers

I need to read the previous books from this author because based on the reaction I got when I posted about reading this ARC this author is a MUST READ.
I obviously haven't ever read this author before, but this novel wasn't hard to follow and it dragged me in from the very start.
This read follows Sybella and Beast and I don't want to give anything away since I guess this was a book people are dying for. I plan to go back and read the previous series that this finds off for because if it impacted me this much with not having the backstory, I can't image the punch the it is going to pack when I have that story.
Synopsis:
Death wasn’t the end, it was only the beginning…
Sybella has always been the darkest of Death’s daughters, trained at the convent of Saint Mortain to serve as his justice. But she has a new mission now. In a desperate bid to keep her two youngest sisters safe from the family that nearly destroyed them all, she agrees to accompany the duchess to France, where they quickly find themselves surrounded by enemies. Their one ray of hope is Sybella’s fellow novitiates, disguised and hidden deep in the French court years ago by the convent—provided Sybella can find them.
Genevieve has been undercover for so many years, she struggles to remember who she is or what she’s supposed to be fighting for. Her only solace is a hidden prisoner who appears all but forgotten by his guards. When tragedy strikes, she has no choice but to take matters into her own hands—even if it means ignoring the long awaited orders from the convent.
As Sybella and Gen’s paths draw ever closer, the fate of everything they hold sacred rests on a knife’s edge. Will they find each other in time, or will their worlds collide, destroying everything they care about?