This is a 3.5 for me but stopped just short of a 4. 
 I did this as a buddy read with my friend Poonam . 
 I loved the first book Wolf by Wolf and I was lucky I did not have to wait long for Blood for Blood. But a lot of things that made Wolf by Wolf great was missing in this book. 
 Spoilers ahead for the first book in the series.... 
 The book continues from where Yael just killed Hitler and is on the run. Luka in an attempt to clear his name, since he invited her to the ball, runs after Yael/Adele. Felix joins the duo in attempt to clear his sister Adele's name. Their journey back to Germania is captured well though it gets too long in the middle. 
 (view spoiler)[ Yael and Luka's capture, Felix being introduced as a double agent, Miraim making a return, their journey back into the death camp and the final reveal are the key highlights of the story (hide spoiler)] 
 But the book was predictable in most parts, with less intrigue and not as much politics (view spoiler)[ not much is shown towards the end after the truth of Hitler's death is revealed. Although I am not averse to tragic endings killing Luka in the end did not do much for the book and I feel the story would have worked out just as well if he had lived. I also did not like the tattoo she got in Luka's memory, a lion just did not do it for me. (hide spoiler)]. 
 Character review: 
 Yael: The first book shows her as a strong driven character but this one watered down her strengths in an attempt to show her vulnerability. I wish she had remained kick-ass. 
 Luka: Was a treat to read. Loved his dry sense of humour and is definitely the character with the most growth throughout the series. 
 Felix: How I hated him!!! But I get why the author wrote his character as such and (view spoiler)[ choosing between your family or unknown people even if they are part of a much greater cause is tough (hide spoiler)] 
 Adele: Such a pain!!! 
 (view spoiler)[ Miriam: She was strong and driven and was the force that was missing in Yael. (hide spoiler)] 
 Overall, the writing was not as tight and some parts were stretched. With better editing this would have been a 4 and without all the loopholes it could have easily been a 5 for me.