The skitarii are the soldiers of the Machine God, the tireless legions of the Adeptus Mechanicus. Holy warriors, they carry the word of the Omnissiah across the galaxy, destroying impure machines and spearheading the Quest for Knowledge. A discovery of ancient technology sends a skitarii legion into battle on a forge world overrun by Chaos. When a cataclysm cuts him off from his tech-priest overseers, Stroika must rally his forces and battle both corrupt machines and Chaos Space Marines.

As Guilliman, Regent of Terra, heads off to lead the Indomitus Crusade, he leaves behind a world still in turmoil, beset by cult activity. Stripped of its huge armies for the galactic offensive, recovery is precarious. The Custodians do what they can while keeping the Palace secure, and the Sisters of Silence rebuild their citadel on Luna. When the warship Phalanx returns, it seems that stability will at last be assured. However, as reconquest forces push out further into the slums, they come across signs that another mysterious foe is active.

Before the being called the Emperor revealed himself, before the rise of the aeldari, before the necrontyr traded their flesh for immortal metal, the world was born in violence. Even when they inhabited bodies of flesh, Trazyn the Infinite and Orikan the Diviner were polar opposites. Trazyn, a collector of historical oddities, presides over a gallery full of the most dangerous artefacts - and people - of the galactic past. Orikan, a chronomancer without peer, draws zodiacs that predict and manipulate the future. 

Pursued by vengeful eldar, Magos Kotov’s Explorator armada heads into a newly revealed area of space in pursuit of ancient secrets. As the Adeptus Mechanicus forces and Black Templars Space Marines tackle the twin threats of the wrathful aliens and insurrection aboard the fleet, a greater danger reveals itself.

Of the billions of greenskins who swarm the galaxy, the name of one strikes fear into the hearts of human and xenos alike—Ghazghkull Mag Uruk Thraka. The Warlord of Warlords. The Beast of Armageddon. The Prophet of the Waaagh! With his tusks, fists and power claw, he does the holy work of Gork and Mork—and soon all worlds will burn in his bootprints. Mystery shrouds the origins of such a beast. Rumours abound that the mighty warlord was once just like any other ork—but if that is the case, how did he rise from a lowly lad to the biggest of bosses? 

A great darkness has befallen the galaxy, and the armies of Chaos are rampant. To survive, humanity must retaliate and take back what they have lost. By the will of the reborn primarch, Roboute Guilliman, is the Indomitus Crusade launched - a military undertaking that eclipses all others in known history. From the Throneworld of Terra does the Avenging Son hurl his fleets, their mission the very salvation of mankind.

The paths of Roboute Guilliman and his fallen brother Mortarion bring them inexorably together on Iax. Once a jewel of the Imperium, the garden world is dying as the plans of the Lord of Death to use it as a fulcrum to drag the stellar realm of Ultramar into the warp come to deadly fruition. While Guilliman attempts to prevent the destruction of his kingdom, Mortarion schemes to bring his brother low with the Godblight, a disease created in the Cauldron of Nurgle itself, made with the power to destroy a son of the Emperor. 

The Night Lords were once among the most potent forces of the Imperium, Space Marines who used fear itself as their weapon. Now, cast adrift from the Emperor's light and hunted as heretics after their monstrous betrayal, the Night Lords clad themselves in symbols of death and fight the Long War, bringing pain and terror to all who worship the corpse-god of Terra. A summons from Warmaster Abaddon sends these rebels on a dangerous journey that leads inexorably to a conflict with the Emperor's chosen warriors, the Blood Angels.  

In the void and upon the worlds of Greater Ultramar, the battle for the Imperium continues. Intent on rebuilding his home realm and using it as a base to reconstruct the ravaged stellar empire of mankind, the returned primarch, Roboute Guilliman, proceeds with his war to drive Mortarion and his Death Guard Traitor Legion from the domain of the Ultramarines. But when Guilliman brings his brother to battle upon the diseased plains of Parmenio, the intervention of a greater power in their fraternal struggle threatens to upend the Imperial Regent’s understanding of the galaxy. 

On the ice world of Simia Orichalcae a spate of mysterious disappearances is causing unrest amongst the mine workers, and, as senior officer of the Astra Militarum, Commissar Ciaphas Cain is nominated to investigate. Unbeknownst to him, the planet is right in the path of a major ork incursion, and, as the savage greenskins attack, a malevolent evil begins to stir deep in the ice caves. 

Ufthak Blackhawk and the green tide descend upon Hephaesto - an Adeptus Mechanicus forge world bristling with loot - only to find it already under siege by the notorious Freebooter Kaptin Badrukk. When his warboss, Da Biggest Big Mek, orders temporary co-operation, Ufthak seeks to make a name for himself by crushing some of the Imperium’s most advanced defenders and claiming the greatest prize. 

Once a loyal son of the Emperor's Children, Fabius Bile now loathes those he once called brother. But when a former comrade requests his aid on a mission he cannot refuse, Bile is drawn once more into the sinister machinations of his former Legion. Now, accompanied by new allies and old enemies alike, Fabius Bile must travel deep into the wilds of the Eastern Fringe, in search of a world unlike any other. A world which might hold the key to his very survival. A world called Solemnace....

Imperial commissar Ciaphas Cain returns to Nusquam Fundumentibus to crush the ork attacks which have been plaguing the frozen planet. But when his ship crashes into the wastelands outside the capital it disturbs a far greater enemy, one which has lain dormant under the permafrost since long before the Imperium came to this world and could now threaten the whole sector.

Legend tells of a foolhardy expedition, led by the radical Magos Telok, that ventured out into the unknown space beyond the Halo Worlds in search of the 'Breath of the Gods' - an arcane device with the power to unmake and reshape the very stars themselves. Thousands of years later, the ambitious Lexell Kotov musters his Adeptus Mechanicus Explorator fleet and sets out to follow in mad old Telok's footsteps. 

Follow the exploits of Oltyx, who, having finally been granted the throne of the Ithakas Dynasty, now faces far greater threats, from within and without. He soon learns that the lessons of kingship are not quite what he had hoped.