Codex: Chaos Daemons (2018), p29-31 — Chaos Rising

M34-36 The Quickening

Once more the Imperium is beset by civil war in the Age of Apostasy. It is a time of false prophets and intrigue, of anarchy and war, and in the end, plague. As the stages of the Age of Apostasy unfold, Tzeentch, then Nurgle, become the dominant powers within the Realm of Chaos.

[...]

Deluge of Sickness

The droughts of Gaero Alphus worsen and eventually, all animal life is sacrificed to feed the tribes' gnawing hunger. The heat drives the tribesmen to pray for divine aid. They turn to the rain dances of old, even sacrificing their own people in the hope of ending the drought. Grandfather Nurgle and his minions hear, take pity, and grant their wish. Glorious rain comes, but as each day passes, the clouds thicken and grow more menacing. Deserts turn to lakes, arid croplands to rotting soup. Disease grows rampant. On the eighth day, the Tallyman of Nurgle, Epidemius, pushes his way out of the sludge to catalogue the disaster. As constant rain lashes down, the Pathogenus Legions arrive to overcome all. A week later, Gaero Alphus disappears altogether from all Imperial records. Eight entire systems follow, with Rotigus Rainfather leading the Epidemic Legions to spread Nurgle's generosity to surrounding worlds.

[...]

M38-40 A Red Age Dawning

The incessant warring of this period sees the rise of Khorne in the immaterium, and the Blood God is once more first amongst the Great Game's players. The chief victim of Khorne's rise is Nurgle, who falls below all his brothers in power.

[...]

The Living Plagues of Thruscas Sine

The heretically progressive world of Thruscas Sine eradicates all natural illness from its populace. Nurgle is offended, and infests the world from pole to pole. The Plague Legions run amok, and there are no survivors save a new pestilence that will continue to grow in virulence.

[...]

M40-41 Time of Ending

[...]

Fall of the Seers of Lugganath

The craftworld of Lugganath falls prey to the Brittle Coma. Its Seer Council project their spirits into the Garden of Nurgle, hoping to find the cure, but instead they meet a tragic and unsettling end.

[...]

The Scourge Stars

Nurgle sends forth from his garden dozens of Plague Legions to overrun the three sprawling star systems to the galactic north of Ultramar. Once conquered, these worlds become a stronghold for the Plague God's mortal and immortal followers.

[...]

The Plague Wars

Issuing forth from the Scourge Stars, Nurgle's Plague Legions begin a lengthy campaign to corrupt Ultramar. Although they achieve many triumphs, final victory is thwarted by Roboute Guilliman's masterful counter-attacks. The ensuing stalemate is only broken when Nurgle recalls much of his strength, ordering his most powerful Greater Daemons and their legions to help defend the Scourge Stars.

[...]

War in the Rift

Tzeentch tricks Khorne into averting his gaze from his Blood Crusade to look instead upon the Scourge Stars. There, the Blood God espies Nurgle's diseased bloomfields blossoming within realspace. Bellowing with rage, Khorne redirects his legions to attack his brother's growing domain. Dozens of Tzeentch's legions follow in their red wake. So begins the War in the Rift - the largest conflict of the Great Game to ever spill over into reality. In response to the invasions, Nurgle launches seven counter-attacks, the largest of which strikes into the Stygius Sector, for the Plague God rightly suspects Tzeentch is behind the assaults upon his realspace stronghold. Even as Kairos Fateweaver leads an assault upon Nurgle's garden, Rotigus heads the invasion of the Stygius Sector. Slaanesh allies with all three of his brothers at different times, his fickle nature drawing the ire of all, but Khorne especially.

The titanic engagements between the Chaos Gods' legions take place across a hundred fronts, but one single battle stands above all others, for none can match the sheer scale of slaughter that occurs upon the planet of Vigrid. Armies clash and powers of such magnitude are released that the planet, now reshaped into a Daemon world, is shattered, the debris shifting into the warp where the surviving combatants continue their battle as they float upon the formless seas of the immaterium. It is a maelstrom of conflict unending, with each side sending in a constant stream of new legions. Seeking an end to the battle, Tzeentch suggests a contest of champions to settle the matter. Each of the Chaos Gods, sure of their own victory, agrees.