I started this series because I wanted to know how Guilliman, with his superior statesman's mind, handles the complicated and intimidating situation of the galactic imperium of humankind. I read this book because I wanted to know how he handles the matter of faith in his father, the God-Emperor.
The thing with Guilliman is that his analytical mind dissects, assembles and utilizes every scrap of information he comes across. Where he sees potential in the state and its people, he enables it.
From the backwards oriented religion of the machine cult, he took the most brilliant to kindle innovation in all matters technology and medicine. In matters of infrastructure, he is faced with sedition and attrition, but turns those into unity and cohesion. For warpcraft, too, he fights against superstition and ritualism in order to harvest the potential these mutants of mankind have to offer.
But everything related to the faith, he opposes. And I was dumbfounded when he himself admitted that his sole reason for such bearing is ignorance. He has seen the sentient Light emanating from the Golden Throne, he knows the Emperor is not truly dead. He knows the Battle Sisters perform acts of Faith all the way up to miracles and living saints, turning the tides of battle in mankind's favor. Yet still he opposes all things faith. In all other matters, he keeps a cool head, taking in information, bit by bit, and sorts it out eventually. But information educating faith he blocks, sustaining his ignorance in this fashion.
I can not over-emphasize how much I love these philosophical, spiritual debates within the 40k universe. Thanks to the warp, godlike entities are real enough, daemons plow the universe, and witchcraft is scientifically exploitable, if not always explicable. Things happen to be real, but all of them are slippery slopes to damnation - for the individual, and all of mankind.
By means of the Deathguard and Nurgle's daemons who oppose the home system of Guilliman, we get pretty close up and personal with some of the warp's evils. The battles are entertaining, though Haley presents them always with a theme, a lingering exercise of though that won't fully go away, communicated through action rather than dialogue. And I discovered listening to classical music while reading these chapters amplifies the merriment.
I almost rage-quit reading just because Guilliman had so many opportunities to educate himself, which he refused to take. To omit further spoiler: Haley simply outdid himself. He is juggling with all the different perspectives and conceptions of the matter, always setting his narrative fully into the character, nature and identity of the characters at play. And before the final page is turned, all the pieces fall together.
I am not saying that there is a simple answer to everything, a straight forward conclusion, never that. True to 40k paradigm, the reader is free to decide for themselves which perspective convinces them most. It's what is making this another 5/5 stars book of the franchise, recommendable to anyone interested in the indulgence.