As every other Space Marines Battles novel it starts with a transmission.
The liberation of Shardenus has begun. The faithful shall be martyrs. Death to the traitor and heretic.
Be vigilant. Do your duty. We will be watching.
This transmission is broadcast to the human forces about to lay siege to Shardenus, a world who has fallen to the heretics, but most of the population don't even know it, the soldiers of Shardenus crying out to the Emperor as they fall. Shardenus is a well fortified hive world so the fighting I'd fierce, and the Iron Hands deploy their human forces without regard to safety, causing heavy casualties. Every human soldier that falls spares a Space Marine from a bullet, and Space Marines are by far a more valuable resource than a human.
Lord General Raji Nethata watches in frustration as his men fall to enemy guns, like wheat before a scythe. As a experienced commander, a master tactician, and loyal servant to the throne he does not understand the tactics used by the Iron Hands. They seem to be disregarding sound strategy by neglecting to securing flanks and supply line, rushing forward instead of laying siege and waiting for the resources of Shardenus to run dry. Any communication sent to the Iron Hands is either ignored or answered with more demands for speed and reckless advancement. In a desperation he reaches out to Magos Ys, in charge of the Adeptus Mechanicus contingent deploying the Legio Astorum, who advices him the Iron Hands only understand strength. The Lord General knows he can be strong to save the men and women under his command for being turned into to mince by the guns of Shardenus.
A core theme in Warhammer 40k is how everyone plays a role in the Empire of Man, it might be a small role, but the toil of an endless number of humans, their blood and sweat greasing the wheels, is what drives the engine of this vast machine. However, it is their duty to bleed for the Empire, not their right, and disobedience is punished. There is room for mercy and weakness when we are surrounded by enemies. This is tested to its limit in Wrath of Iron, the enigmatic approach by the Iron Hands, they have lost too much humanity to understand the suffering they inflict, but their sacrifice was necessary to fight the enemy.
What I really like about the Space Marine Battles novels is the large scale conflict, and how you get to follow a wide variety of forces. We are told the story from the view of a Warlord Titan, Space Marines, soldiers and also a lone assassin, who has infiltrated the hive world.
Valien, a Death Cult assassin, is the most fun to read about, as he worms his way deeper and deeper into enemy territory. A twisted man, once a terrible man who killed for pleasure, now seeking redemption by killing for the Emperor. His deadly needle gun and taste for blood makes for a gristly, but highly entertaining read. The suspense is heightened as he penetrates further behind enemy lines, normal people being replaced by mutants, the walls by living flesh. He suspects he is closer to his goal, sharp fellow :)
Morvox, one of the Iron Hands younger members, is conflicted about their methods. Flesh is weak, this humans are, weak, but is it not their purpose to protect the weaker. He even questions his orders, wanting to stand between the human soldiers and the spawns of Chaos, but he is reprimanded and forced to move on.
This young Space Marine's plight adds more context to how different they are from mere mortals. It also tells us more about how even more alien the Iron Hands are, with their distaste for their flesh bodies.
Chris Wraight's Wrath of Iron is a good read, and another fine addition to the Space Marines Battles novels. As always, it's about spilling blood for the Emperor of Mankind, your own, or your enemies'.
Although I enjoyed reading it, I can't help feeling Chris Wraight let in a flaw in his plot. The friction between the Space Marines and their allies could have been avoided had they simply been more open and honest with their goals. For super soldiers, they really are super stupid sometimes.
Wrath of Iron weighs in at 416 pages, and is published by Black Library.