That grand introduction I just did is a bit misleading, because it doesn't capture the spirit of Dark Imperium. Haley's novel, the first to chronicle any of the events unfolding in this brave new 8th-ed galaxy, doesn't have a grandiose, overly-dramatic story arc. Its pages aren't clotted with the viscera of battle scenes, and the chapters don't grind out the same drumbeat of endless war we've heard a thousand times before. Haley has written a much smarter novel than that.
The new status-quo introduced in the 8th edition of Warhammer 40K simply cannot be encompassed by a single novel. What Haley has achieved is a book that gives readers a sense of the broader picture without collapsing beneath its weight. Set mainly in Ultramar, Dark Imperium brings the Indomitus Crusade to a close as Guilliman hurries home to combat the threat of Mortarion, providing varied insights into the changing Imperium along the way. By sticking to this loose narrative Haley is able to explore many rewarding aspects of the new setting, from the dissolution of the Primaris Space Marines into their parent chapters to the clash between Guilliman's 30K mindset and the grim darkness of the far future. He handles the primarch himself with aplomb, crafting a nuanced version of Guilliman whose struggles against the immense difficulties of his new position humanise him in a way I haven't seen before. His dislike of Cato Sicarius is the icing on the cake.
Dark Imperium lacks a singular antagonist; while Mortarion makes an appearance he never confronts Guilliman. Instead, the power of Nurgle itself is made the enemy, literally manifesting through a subplot that plays out in a hospital on Iax. The human soldiers convalescing there provide a counterpoint to Guilliman's rarefied perspective, anchoring part of the story in human experiences. Introducing Nurgle as an insidious threat that builds to breaking point was a masterstroke, and the panoply of horror that results is as glorious to read as it is repulsive. I expected Guilliman to come to Iax's rescue and therefore tie the main strands of the story together, but that isn't the story Guy Haley has written. Dark Imperium is an introduction, and the big picture matters more than narrative structure.
It isn't often that a novel subverts my expectations in a good way, but Dark Imperium did. It is a collection of different elements that together tell a story that was needed rather than one that was expected. It is both a continuation of all that has come before and the stepping off point for a whole new paradigm, and I cannot think of anything that embodies the spirit of 8th edition more than that.
