Valorous Heart. Our Martyred Lady. Bloody Rose. These names of Adepta Sororitas orders are famed across the galaxy, as are the Battle Sisters who serve the emperor's will. To die in the name of the God-Emperor of Mankind is to live eternal, and none are more willing to bleed in his name than the Adepta Sororitas - the Sisters of Battle. The Book of Martyrs charts the deaths of these exemplars.

The Sisters of Battle are the Emperor's most devout worshippers, fierce warriors preaching the purity of the Imperium and scourging their enemies with bolter and flamer. On a distant world, the Ecclesiarchy outpost of Sanctuary 101 was wiped out by an implacable foe - the fearless, soulless necrons. Now, a mission of the Sisterhood has returned to reconsecrate the site - but the metallic nightmares still lurk in the darkness, guarding a secret that has lain dormant for millennia.

Opal is a gleaming shrine world of saints and soldiers, beloved of the Emperor Himself. Sent to retrieve the skull of the revered Saint Veres, Sister Superior Augusta of the Order of the Bloody Rose and her squad find themselves in the midst of the capital’s holiest festival, a time of reverence and celebration. But all is not well – despite what its planetary leaders would have Augusta believe, political danger bubbles under the surface, and rebel attacks gnaw away at the city’s outskirts. The greatest threat, however, is yet to come.

With her mighty wings spread wide and Ardent Blade aflame, Saint Celestine is the living embodiment of the God-Emperor’s wrath. Her halo blazes like a star upon the smog-wreathed, blood-soaked battlefields of the 41st Millennium; its holy light leading the faithful to victory time and time again. As heretics and daemons tear at her flesh, she calls down fires of retribution from on high to smite the wicked and unrighteous. If she is to fall in battle, none should mourn as she is Celestine, the Living Saint, and death is her duty.

In the grim nightmare future of the 41st millennium, the witch-hunting zealots of the the Sisters of Battle stand between humanity and damnation. From the elite Seraphim warriors to the berserk Sisters Repentia, they are the strong arm of the Ecclesiarchy and the brutal hammer of witches. When dangerous psychic heretic Torris Vaun escapes from her custody, Seraphim Miriya is disgraced in the eyes of her fellow sisters and superiors. Following Vaun's trail to the planet Neva, Miriya takes her sisters in pursuit and, along with Hospitalier Sister Verity, starts her investigations.

During the turbulent Reign of Blood, a great schism in the Imperial Ecclesiarchy threatened all of Terra and promised a darkness to rival the terrors of Old Night. Fell times have come again to the Imperium, and a War of Faith appears inevitable. Standing in the way of catastrophe is Celestine, the Living Saint and one of the greatest heroes of the age. Only she can reunite the warring factions of the Ecclesiarchy and prevent a second Reign of Blood.

Throughout the tortured galaxy, Ephrael Stern is known by many names. The Thrice-born. The Daemonifuge. The Heretic Saint. Trapped deep within Imperium Nihilus following the coming of the Great Rift, the maligned Sister of Battle fears the Imperium is no more. The God-Emperor’s light, which has guided her through centuries of strife, has too extinguished. Seemingly forsaken, Stern is bereft until a mysterious stranger arrives, offering her a new destiny. One that might yet see the Imperium saved. Stern must prove herself worthy of the God-Emperor’s grace once more.

In the city of Queen Mab, nothing is quite as it seems. Pariah, spy and Inquisitorial agent Alizebeth Bequin is all of these things and yet none of them. An enigma, even to herself, she is caught between Inquisitors Gregor Eisenhorn and Gideon Ravenor, former allies now enemies who are playing a shadow game against a mysterious and deadly foe. Coveted by the archenemy, pursued by the Inquisition, Bequin becomes embroiled in a dark plot of which she knows not her role or purpose.

Uncompromising and fierce, Commissar Severina Raine has always served the Imperium with the utmost distinction. Attached to the 11th Antari Rifles, she instills order and courage in the face of utter horror. The Chaos cult, the Sighted, have swept throughout the Bale Stars and a shadow has fallen across its benighted worlds. A great campaign led by the vaunted hero Lord-General Militant Alar Serek is underway to free the system from tyranny and enslavement, but the price of victory must be paid in blood.

The Custodian Guard have stood watch over the Emperor's Palace on Terra since the foundation of the Imperium. Charged with protecting the Master of Mankind from all threats, within and without, their fearsome resolve is renowned throughout the galaxy, and their golden armour is the last thing that a would-be assassin or saboteur will ever see.

When Horus fell, his Sons fell with him. A broken Legion, beset by rivalries and hunted by their erstwhile allies, the former Luna Wolves have scattered across the tortured realm of the Eye of Terror. And of Abaddon, greatest of the Warmaster's followers, nothing has been heard for many years. Until now....

Under almost constant besiegement by the hosts pouring from the Eye of Terror, Cadia acts as a bulwark against tyranny and death. Its fortresses and armies have held back the hordes of Chaos for centuries, but that grim defiance is about to reach its end. As Abaddon's Thirteenth Black Crusade batters Cadia's defences, and armies of the Imperium flock to reinforce this crucial world, a terrible ritual long in the making comes to fruition and the delicate balance of this brutal war shifts.

After seven long years of conflict, the Horus Heresy nears its end. But now, as the Warmaster Horus marches on Terra to rip his father from the Throne, the seat of the arch-traitor’s power lies empty. Cthonia, a world once dominated by brutal murder-gangs, is occupied by the Emperor’s praetorians—the indomitable Imperial Fists. For the Sons of Horus, this outrage demands a reckoning.

The feral warrior-kings of Fenris, the Space Wolves are the sons of Leman Russ. Savage heroes, few can match their ferocity in battle. After half a century apart, Space Wolves Ingvar and Gunnlaugr are reunited. Sent to defend an important shrine world from the plague-ridden Death Guard, the Grey Hunters clash with the pious Sisters of Battle—who see the Space Wolves as little better than the enemy they fight. As enemies close in around them and treachery is revealed, Gunnlaugr and his warriors must hold the defenders together.

On the forge world of Morod, the machines never stop and the work never ends. The population toils in the mines and factoria to protect humanity from the monsters in the void, while the Adeptus Mechanicus enjoy lives of palatial comfort. Genetor Gammat Triskellian seeks to end this stagnant corruption. When he learns of a twisted congregation operating within the shadows, one which believes that the tech-priests are keeping people from their true salvation, he sees in them an opportunity to bring down Morod's masters and reclaim the world in the name of progress.