So, this is Henry Zou's sort of prequel/follow up to Emperor's Mercy which followed an Inquisitor fighting (and mostly passing out) a Chaos warband lead by a guy Khorsabad Maw.
This is the "birth story" of Maw, who starts out as a loyal Guard officer and ends as something else. The author obviously took lots of inspiration from the brown water campaigns in Vietnam with bits of the LRPG's and Aussie troops in the same war. Thankfully absent is his tendency in the previous novel to "modernize" it by slapping an acronym or meaningless jargon onto things, that didn't really fit into the universe.
Refreshing is his take on Chaos in the novel, rather then being a force moustache twirling villains, the characters are largely folks fighting for their homes against a complete asshole of a Cardinal. Also refreshing is the appearance of Traitor Marines is confined to five individuals who aren't frothing at the mouth screaming for blood and skulls.
I'd call this a good read and hopefully as the series progresses he'll drop the weird political/moral ramblings that are obviously a consequence of his service in Afghanistan.