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. 

Fell times have come to the galaxy. Cadia has fallen, destroyed by the onslaught of Chaos. A Great Rift in the warp has opened, and from its depths spew daemons and the horrors of Old Night. But all hope is not lost… A hero, long absent, has returned, and with him comes the wrath of the Ultramarines reborn. Roboute Guilliman has arisen to lead the Imperium out of darkness on a crusade the likes of which has not been seen since the fabled days of the Emperor. But never before have the forces of Ruin amassed in such numbers, and nowhere is safe from despoliation. 

Exile to the miserable world of Sedh, the disgraced Necron Lord Oltyx is consumed with bitterness. Once heir to the throne of a dynasty, he now commands nothing but a dwindling garrison of warriors, in a never-ending struggle against Ork invaders. Oltyx can think of nothing but the prospect of vengeance against his betrayers, and the reclamation of his birthright. But the Orks are merely the harbingers of a truly unstoppable force. Unless Oltyx acts to save his dynasty, revenge will win him only ashes. 

After a series of victories, the Imperial forces are on the back foot once more. The power of Chaos is rising, the Traitors gain ground, and all hope seems lost. Can Terra endure? 

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. 

The Inner Walls are breached. Traitor vanguards tear towards the heart of the Palace, sensing victory. Desperate gambits are attempted: an unwilling saint is released into the ruins, as well as an enthusiastic sinner. A black sword rises, forged from spite, ready to create a legend. But amid the slaughter, Jaghatai Khan, Warhawk of Chogoris, prepares to launch the most audacious strike of the conflict. His goal is nothing less than the liberation of the Lion's Gate space port. 

In the mysterious city of Queen Mab, the forces of light and darkness are locked in a murderous struggle for truth. The dedicated agents of the Holy Inquisition battle with their shadowy counterparts, the infamous Cognitae, to discover the encrypted identity of the enigmatic, all-powerful King in Yellow. Caught at the heart of this struggle is the pariah Alizebeth Bequin. Bequin must withstand an onslaught of angels, daemons, and even the monstrous warriors of the Traitor Legions, to unpick the greatest riddle of her life. 

Belisarius Cawl, Archmagos Dominus of the Adeptus Mechanicus, is the most brilliant mind alive. For 10,000 years he has furthered the cause of mankind, working under the aegis of the Emperor and Lord Commander Roboute Guilliman to prevent the inexorable march of the alien and the traitor. Many call him heretic, but all must recognise the magnitude of his achievements, for who else but he was entrusted to create a new generation of Space Marines?  

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.  

On the battlefields of Aexe Cardinal, the stalwart forces of the Imperial Guard are locked in a deadly stalemate with the dark armies of Chaos. Colonel-Commissar Ibram Gaunt and his regiment, the Tanith First and Only, are thrown headlong into the living hell of trench warfare, where death by an unseen enemy is always just a moment away. The only chance for Gaunt and his lightly armed scouts to survive is to volunteer for a mission so dangerous that no one else dares accept it.

After a long and distinguished career defending the Imperium from its many enemies, Commissar Cain is enjoying a well-deserved retirement on Perlia, teaching in a schola progenium. But when a Black Crusade threatens the sector, all able-bodied citizens must rise to the defence, including Cain and his cadets. As the forces of Chaos overwhelm Perlia, can the wily commissar prove himself to be a real hero of the Imperium one last time?

Driven on by their hatred of the False Emperor, the Night Lords stalk the shadows of the galaxy, eternally seeking revenge for the death of their primarch. Their dark quest leads them to a fractious alliance with the Red Corsairs, united only by a common enemy. Together with this piratical band of renegades, they bring their ways of destruction to the fortress-monastery of the Marines Errant.

The Warmaster’s horde advances through the fire and ash of Terra's dying breaths, forcing the loyalists back to the Delphic Battlement—the very walls of the Sanctum Imperialis. Angron, Primarch of the World Eaters and Herald of Horus, has achieved immortality through annihilation—now he leads the armies of the damned in a wrathful tide, destroying all before them as the warp begins its poisonous corruption of Terra's very soil.

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.

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.