Jaeger - Simon Bestwick

"Roth-Steyr, the story of Valerie Varden (or to use her full name, Countess Valerie Elisabeth Franzsiska von Bradenstein-Vršovci, reluctant immortal and former assassin of the Habsburg Empire) wasn't quite like anything I'd written before. And almost as soon as I'd finished it, I knew Val had more to say. So I picked up her trail again, and found her making her way across a darkening Europe, hunted by a shadowy foe. Someone wants her dead: to find out who Val will need to remember everything she tried to forget. She must become, once more, an assassin. A killer. A Jaeger."