Chapter Summaries

Guilliman inspected Cawl’s primaris Space Marines and reviewed modifications found in the Luna Wolves, concluding that their creator aimed to end Astartes supremacy by making them more empathetic. He left the chapter considering how difficult it would be to introduce such reforms in the suspicious Imperium.

• After speaking with Dorn, Guilliman visited Cawl’s underground facility and saw two primaris Space Marines fighting.
• Cawl reported that the primaris Space Marines exceeded their projected performance and were ready for deployment, but Guilliman said their introduction would take time.
• Guilliman examined Cawl’s autopsy report on Astartes whose gene-modifications included removed procedures and additions suspected of involving Warp contamination.
• Guilliman learned that the modifications increased Astartes emotional responses and explained that their creator wanted to challenge Astartes supremacy.
• Guilliman considered the creator’s rules against sacrificing civilians and reflected that the Imperium’s leaders and Chapters would resist changes.

Bona authorized limited frontline use of the Dark Mechanicum’s Frenzied Automata after learning about the Imperium’s Primaris Space Marines, then traveled to Hexen Fortress World to investigate a Thousand Sons force’s surrender. His journey ended in a Necron ambush led by Amarkun the Punishment King, who demanded a conversation and threatened to destroy Bona’s escort fleet.

• Fabricator-General Antonia showed Bona the Frenzied Automata, daemonhost-powered combat robots, and argued they were needed to counter the Primaris Space Marines.
• Bona authorized a small batch of Frenzied Automata for frontline use only with approval from both the frontline commander and the Commissar.
• Horus told Bona that a Thousand Sons force had surrendered after splitting from Ahriman’s group, which remained loyal to the Lord of Change.
• Bona boarded a cruiser for Hexen Fortress World and tried to rest while considering why the Thousand Sons had divided.
• A Necron fleet ambushed Bona’s escort, and Overlord Amarkun the Punishment King invited him to talk while warning that the fleet would be destroyed within ten minutes.

Bona surrendered himself to the Necrons to protect a transport fleet carrying forty million colonists, then escaped his containment and attacked their warship. He unleashed the Iron Plague and planned to destroy the ship’s power core as Necron forces closed in.

• Bona offered to go with the Necrons, and they stopped their assault and took him through a portal while the surviving fleet remained behind.
• Aboard an Eternal Dread-class battleship, Amarkun ordered Zaa to examine Bona before handing him over to Trazyn.
• Bona appeared outside his containment, struck Amarkun and Zaa, and killed more than a dozen Lychguard.
• Bona used his Bolter to sever his left ring finger, then drew a ritual circle and summoned seven strains of the Iron Plague.
• The Iron Plague spread through the living metal as Necron Warriors advanced, and Bona prepared to destroy the ship’s power core.

Bona reached the Necrons’ Engine Room and was trapped in another space with a strange being named Magladroth, who revealed that he was a C’tan. The two agreed that the Necrons had imprisoned them and decided to look for a way out.

• Amarkun ordered his crew to send Bona into the Transdimensional Cube Prison.
• Bona entered the Engine Room and found that its tower had opened into another space.
• Magladroth attacked Bona, but the two recognized each other as unusual beings and stopped fighting.
• Bona gave Magladroth his Dataslate, allowing Magladroth to learn human language and introduce himself as a C’tan.
• Bona and Magladroth agreed to search for a way out of the Necrons’ prison.

Bona and Magdaleros built a device to escape the warp, but Magdaleros merged with Bona and shared his power before they could use it. After Bona’s emergence destroyed Amarkun’s flagship, he confronted the Necrons and learned that Trazyn the Infinite had commissioned the attack.

• Under Magdaleros’s guidance, Bona built a device that could connect to the warp and overload their prison.
• Magdaleros shattered himself and merged into Bona, allowing Bona to sense his other instances, including one on Mars and one near Holy Terra.
• The device’s eruption tore apart Amarkun’s flagship and swept nearby Necron ships and Canoptek Scarabs into a warp rift.
• Amarkun’s fleet used its Blackstone Systems to destabilize and close the rift after daemons spilled into the void and attacked the Necrons.
• Bona disabled Zaa’s command and rewrote Amarkun’s logic, then learned that Trazyn the Infinite had hired the Necrons to attack him.

Bona and Amarkun tricked Trazyn, taking the Dark Throne activation key and leaving Trazyn defeated. Bona returned to Hexen in a captured Necron warship, where Archmagos Antonia began inspecting it and revealed that Horus was on his way.

• Trazyn delivered the Dark Throne activation key to Amarkun and tried to claim his specimen, but Bona and Amarkun revealed they had made a deal behind his back.
• Bona knocked Trazyn unconscious and took his head, while Amarkun let Bona escape in a Necron cruiser after they agreed their cooperation was temporary.
• Bona used the cruiser's Inertialess Drive to reach Hexen in less than a day and identified himself to Imperial forces, who escorted the warship to Mooring Zone Six.
• Archmagos Antonia demanded the warship's control commands and auxiliary units, then boarded it to inspect the technology.
• Archmagos Antonia told Bona that Horus had already set out and would soon arrive on Hexen.

After returning to Hexen, Bona reviewed the empire’s affairs and chose to expand toward the T'au Empire while considering a risky plan involving Trazyn’s data core. Meanwhile, Magnus led the Thousand Sons into the Emperor’s flames, where most of his sorcerers perished, and emerged with a handful of wounded survivors to begin their atonement.

• Horus and the senior officials arrived on Hexen, and Bona spent two days catching up on the war and reviewing important documents.
• Bona decided to summon the T'au envoy and expand toward the T'au Empire, while agreeing to send troops to aid Ultramar against Nurgle.
• Bona discovered what Magnus was doing with the Book of Omniscience and prepared to attempt something important using Trazyn’s data core.
• Magnus told the Thousand Sons Sorcerers that they could leave him, but they chose to follow him through a Warp rift.
• Magnus and the sorcerers entered the Emperor’s inferno, where nearly all of them were burned to ashes.
• Magnus returned to the Materium with barely a dozen surviving sorcerers and told them their road to atonement remained long.

Bona used a willing soul to restore Trazyn as a living human, then asked him to bring the Necrons over to his side. Trazyn agreed to seek an audience with the Silent King, though he could not promise what the Triarch would decide.

• Bona summoned a nameless soul, erased its memories, and guided it into a clone after completing his work on Necron protocols.
• The clone awakened as Trazyn, discovered he had become human, and began experimenting with sensations and risky activities.
• Bona retrieved Trazyn after his antics drew an Inquisitor's attention, and Trazyn seized his mechanical head when Bona threatened to activate the real Trazyn.
• Bona asked Trazyn to bring the Necrons to his side and argued that they could not recover their souls without reaching the Warp.
• Trazyn agreed to seek an audience with the Silent King, while warning that the decision would not be his to make.

Bona met with the T'au envoy Vre Vem and demanded that the T'au Empire surrender its military and become his vassal. The negotiations failed, and as the T'au fleet prepared for war, Bona resolved to destroy their vision of the Greater Good rather than let humanity be ruled by aliens.

• Bona identified Vre Vem as an inexperienced Water Caste diplomat and opened negotiations by demanding the T'au surrender their sovereignty and armed forces.
• Vre Vem argued that the T'au and Bona's empire could cooperate, but Bona condemned the T'au use of artificial intelligence and rejected their proposal.
• Bona repeated his demand, and Vre Vem warned that the T'au would fight and had authorized colleagues to mobilize a nearby Homeworld's armed forces.
• Bona dismissed Vre Vem and contacted Admiral Spire, Colonel Sakot, and Horus as the T'au fleet powered up at the Spaceport.
• Bona watched the fleet and decided he would destroy the T'au dream rather than allow humanity to be ruled by aliens.

Commander Farsight and Commander Shadowsun were ordered to repel a human faction that had rejected the Greater Good. Meanwhile, Bona weighed the cost of fighting the T'au Empire and named his strategy the War of the Men of Iron.

• Commander Farsight returned from hibernation and learned that humanity had again gone to war against the T'au Empire.
• Farsight and Commander Shadowsun met the Supreme Ethereals, who described Guilliman's crusade and ordered them to defeat the newly risen human faction.
• Bona reviewed intelligence with Admiral Spire, Horus, and Magnus and considered how a costly T'au campaign could disrupt his plans against the Tyranids.
• Bona decided they would have to fight smart and wrote “War of the Men of Iron.”

Bona awoke after enduring a Warp trial in which he repeatedly killed doubles urging humanity to embrace Chaos, and discovered his growing psychic power let him see souls and Warp creatures. He rallied his empire’s forces for an expedition against the T'au, while veteran Commissars warned that the recruits were underestimating their enemy.

• Bona fought and killed countless doubles who argued that humanity should unleash its Warp nature, then saw a black sun appear.
• Captain Dakan and a Biologis found Bona unresponsive, but he woke and dismissed their concerns despite his exhaustion.
• Bona noticed that he could see souls and faint outlines of Warp creatures as his psychic power grew.
• Bona addressed the assembled forces and sent them into the Great Crusade with a speech about humanity’s manifest destiny.
• The empire’s fanatical recruits dismissed the T'au, while veteran Commissars who had fought them urged the soldiers to take them seriously.

Perturabo recalled the neglect and isolation that had defined his ten thousand years on Medrengard, where his grand fortress-world went unnoticed. When Anax reported that Rogal Dorn had returned and insulted him and the Iron Warriors, Perturabo ordered the Legion to muster for a visit.

• Perturabo crushed a mechanical imitation of Calliphone after realizing she was not his sister.
• Perturabo reflected on how the Imperium and Chaos had treated him as a tool and how no one had noticed his utopia on Medrengard.
• Anax told Perturabo that Rogal Dorn had returned, garrisoned a Death World, and called Perturabo a coward and the Iron Warriors idiots.
• Perturabo praised Anax and ordered him to assemble the Legion so they could visit Dorn.

A human infiltration team defended a psychic beacon long enough to guide the Imperial Expeditionary Force through the Damocles Gulf to the T'au Empire. Farsight watched the Imperials establish a foothold near Anreva and grew wary of their unfamiliar tactics.

• Human scouts set up a psychic beacon in Anreva's toxic Underhive, but T'au forces attacked and overwhelmed them.
• The last human soldier detonated a grenade after the beacon transmitted its signal, and Farsight learned the message had reached the Imperium.
• Imperial warships emerged at the Mandeville Point and began building star forts and Astronomican towers instead of launching an immediate assault.
• Farsight ordered the Thunder fleet to probe the Imperial forces, and T'au ships ambushed and damaged several Imperial cruisers.
• A much larger Imperial fleet arrived after roughly half a month of bombardment, forcing the battered Thunder fleet to withdraw as both sides left wreckage near Anreva VI.
• Farsight watched the Imperial fleet reorganize and suspected its commander would be a formidable opponent.

Horus launched an invasion of Anreva, using controlled daemon engines to overwhelm the T'au Empire’s defenses and establish a landing zone. As the Imperium advanced toward its objective, Horus worried that the missing reinforcement fleet commanded by Bona and Magnus had encountered trouble.

• Horus ordered the Adeptus Mechanicus to deploy experimental models as Drop Pods descended on Anreva.
• La'Ruk and Anzes watched daemon engines emerge from the pods and attack the T'au Empire’s troops, vehicles, and defensive lines.
• A railgun destroyed one daemon engine’s power source, and Gue'vesa soldiers dragged the injured La'Ruk back into a trench.
• Horus used psyker power beacons to direct the daemon engines while the Seventh Company secured a landing zone and advanced toward its objective.
• The Imperium’s forces routed the first T'au defensive line in two days, and Horus planned to use captured planets as staging points for an attack on the T'au Homeworld.
• Horus grew concerned when the third reinforcement fleet, jointly commanded by Bona and Magnus, failed to arrive.

Bona encountered T'au'va in the Warp, where she argued for cooperation with humanity before the Third Fleet returned to realspace. On Anreva, the Imperials executed surrendered human soldiers who had fought for the T'au, including Anzes.

• Bona spoke with T'au'va, who said she had trapped the fleet to buy time and hoped the Greater Good would unite species.
• Bona told T'au'va that humanity could not entrust its fate to the T'au Empire, and the Warp veil ruptured, allowing the Third Fleet to arrive.
• Magnus reported the encounter to Horus, who ordered him to move his legion.
• Anreva fell after its defenders ran out of supplies, and Commander V'Lahn surrendered to Aladuc's forces.
• Dawn Army soldiers beat Anzes and shot La'Ruk when he tried to intervene.
• A Commissar presented Anzes and other human T'au troops as traitors, and a firing squad executed them.

At a Necron council, Trazyn appeared in a human body and explained how the Void Dragon, Amarkun, and Bona’s technology were involved. Silent King Szarekh realized that turning the Necrons into humans could leave them vulnerable to the dark gods, and suspected someone was using the offer to gain the Necrons’ strength.

• Szarekh noticed Trazyn sleeping at the council in a Hazardous Environment Suit and ordered him to explain himself.
• Trazyn cut his palm to prove his identity, and Szarekh accepted the evidence that he was truly Trazyn.
• Trazyn recounted how the Void Dragon had returned in another body, Amarkun had helped set him up, and Bona’s technology had played a part.
• Necron Overlords hacked into Trazyn’s systems to question him, then fought one another with viruses for access.
• Szarekh weighed whether the Necrons should remain as they were or become humans, and concluded that someone meant to obtain the strength of the Necron race.

The Dawn Army and the T'au Empire fought a bloody three-month stalemate on Phelio, where a dying human soldier entrusted a Gretchin with his final confession. Horus worried that the war resembled the catastrophic Rangdan conflict, while Bona remained strangely unconcerned by the army’s losses.

• Little Limp scavenged the battlefield with Big Crooked Head, who was killed by a sudden shot.
• Little Limp tried to attack a wounded Fire Caste soldier with a grenade, but it disarmed before an injured Dawn Army soldier killed the T'au.
• The dying soldier, Eric, gave Little Limp his badge and told him to find a Commissar and confess that he had secretly sold the booze.
• The narration described the three-month war on Phelio and the massive forces Thunderhawk and the T'au Empire had committed.
• Horus recalled the devastation of the Rangdan war and wondered how the current conflict would unfold, while Bona allowed the army’s casualties to mount.

Commander Farsight offered to join Shadowsun in a counterattack against the invading human force, and they agreed to attack rather than continue losing warriors in a war of attrition. Meanwhile, Rogal Dorn prepared a trap on Larsk as Perturabo arrived with the Iron Warriors and ordered an assault.

• Shadowsun and Commander Farsight reviewed the T'au Empire's mounting losses and concluded that its defensive strategy was failing.
• Farsight contacted Shadowsun and offered to launch a counterattack from CK-3, warning that new powers were emerging across the universe.
• Shadowsun and Farsight agreed to attack alongside Farsight's forces.
• Rogal Dorn gathered his sons and prepared the Imperial Fists' fortress on Larsk for the Iron Warriors' arrival.
• Perturabo arrived aboard the Iron Blood, exchanged threats with Rogal Dorn, and ordered his forces to attack.

Perturabo attacked Larsk and goaded Dorn before teleporting into the Imperial command hall to fight him. As the Primarchs clashed, an Aeldari Phantom appeared near Perturabo's flagship.

• Perturabo led the Iron Warriors’ assault on Larsk, using Slave Troops and artillery to break through the Imperial Fists’ fortresses.
• Perturabo forced a communications link to Dorn, taunted him, and learned that Dorn had shut down the Planetary Shield.
• Perturabo refused orbital bombardment and ordered Kroeger and the Trident to join him only in the second wave.
• Perturabo teleported into the command hall, where Dorn and the Black Templars were waiting, and the two Primarchs began fighting.
• After Perturabo left his flagship, an Aeldari Phantom appeared in space.

The Aeldari and Imperial fleets defeated the Iron Warriors, and the Phalanx destroyed the Iron Blood, leaving Perturabo’s fate uncertain. After the battle, Guilliman defended cooperation with the Aeldari, while Dorn questioned why Yvraine and Yriel were still present.

• Aeldari forces ambushed Iron Warriors ships and artillery positions, while Primaris Space Marines helped the fortress forces push back the assault.
• Yvraine and Guilliman discussed their cooperation as the Imperial Fleet arrived and joined the battle against the Iron Warriors.
• Perturabo received a distress call, discovered Dorn had teleported away, and ordered the Iron Warriors to retreat.
• The Phalanx fired on the Iron Blood, detonating its Warp Engine and engulfing nearby ships in a warp storm.
• The Imperial Fleet routed the demoralized Iron Warriors, and Guilliman told Dorn they had killed Perturabo.
• Dorn questioned Yvraine and Yriel’s presence, while Guilliman argued that humanity and the Craftworld Aeldari could cooperate.