The Noctis Aeterna (also known as The Blackness and Days of Blinding), was a catastrophic event in the Galaxy following the formation of the Great Rift in the closing days of the 41st Millennium.
Due to the creation of the Rift, the light of the Astronomican was blocked and Astropathic communication rendered impossible. The result, across the Imperium, was a state of total chaos as worlds were cut off. Massive Warp Storms erupted, making Warp Travel extremely hazardous. Riding this wave of Chaotic energy, vast Daemonic legions emerged into the Materium and began to move onto the Galaxy alongside Chaos Space Marines and their Cultist allies.
Time of this blindness greatly varied on every Imperial world. On Terra Astronomican was disrupted for thirtythree days, though on some planets it lasted days or month. It is possible that some regions are still in clutches of Noctis Aeterna.
The effects on the Warp from the creation of the Great Rift eventually wore off, allowing for the reestablishing of communications with some regions and easier Warp travel. This combined with the Indomitus Crusade brought stability to the Imperium once again. However the cost was dire.Slightly less than half of the one thousand Space Marine Chapters remained unaccounted for, and no less than twelve Space Marine Chapter Planets were reported as destroyed during the Noctis Aeterna and the bitter campaigns that followed.
So catastrophic were the effects of the Noctis Aeterna on the Galaxy that time itself has become distorted. In some areas, time slowed. In others, it sped up. The result has been that it has proven quite difficult to categorize modern events.
Notable Events during the Noctis Aeterna
- The Second Battle of Terra.
- The Cadian diaspora defends many worlds around the Cadian Gate including Belis Corona and Agripinaa.
- The Legion of the Damned appears on more than a hundred worlds, including Baal and Armageddon, to fight for the Imperium.
- The White Consuls homeworld of Sabatine is devastated, though the Chapter manages to survive.
- The Sky Sentinels are destroyed by the Thousand Sons led by Magnus the Red himself.
- Orks and Humans often fight alongside one another as Armageddon becomes overrun by the legions of Tzeentch and Khorne. The Chaos forces battle one another in a bid for supremacy.
- Numerous Space Hulks and lost ships emerge from the Warp.
- Hive Fleet Leviathan is largely destroyed in the Devastation of Baal.
- Iyanden is invaded by the Slaaneshi horde of N'Kisha.
- The Tau Fourth Sphere of Expansion is lost due to Warp Storms.
- The Necron Overlord Imotekh, begins the Absorption Wars.
- The Lords of Pain Chapter falls to heresy and turns upon the Imperium.
- The activation of the Ymga Monolith, which causes the Cerberax Wars.
- Khorne's Blood Crusade.
- The Red Tide.
- 1: Warhammer 40,000 8th Edition Rulebook pg.50-53
- 2: Dark Imperium (Novel), Chapter 6
- 3: Gathering Storm: Fracture of Biel-Tan, Chapter 1: The Dance of Destiny - Addenda Inquisitoria
- 4: Watchers of the Throne: The Emperor's Legion (Novel), Chapter Five, Tieron