I have to admit that I truly enjoy this series of books. Story is set in the period after Guillimans return to Terra. Cypher, mysterious Fallen Dark Angel, is part of his entourage. While he assisted Primarch, Guilliman is aware that there is something with Cypher that warrants worry so he sends him in prison under control of Custodes. But since Throne World is under daemonic attack, lots of eyes are looking at Terra and this news will trigger an unexpected action.

While Cypher is narrator this book is not so much about him but about the very nature of the Famous First. Fallen and loyalists clash and old fights the modern. But both so much wrapped in secrecy and mystery that one has to wonder how can Dark Angels function at all. Cypher here is a linchpin, figure that seems to act outside the space and time, master manipulator aiming for something, some ultimate goal and being able to put under his control everyone, from his hunters to chaos infused legionnaires. He is truly a force of nature, and nobody is smarter at the end about him. I think that future books on reawakened Lion will shed more light, especially since the position of Cypher is something that started with the Knights of Caliban, exclusively in Lion's own order if I am not wrong.

Besides Cypher remaining an enigma, novel is beautiful world building experience, showing multiple layers of the Imperium, safety mechanisms, double, triple locks put in place to control the order in Palace and Imperium at large (Custodes Shadowkeepers are excellent, and Doomscryers, oh man these are so Bene Gesseritt :) ).

At the end readers will be left wondering what did I just read. Book is more about mysterious forces vying for control of Palace, heart of the Imperium, and it leaves more open questions than it provides answers. I think this is just prelude to more stories set in shadow war, but even if it remains to stand on its own I think this is great action mystery story.

Highly recommended to all fans of action SF and W40K in general. But dont expect explicit revelations, goal of the book is to highlight the mysterious forces at large, and leave everything to judgement and interpretation of the reader. ( )